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Schwartz's Principles of Surgery > Part II. Specific Considerations > Chapter 30. The Appendix >

KEY POINTS

1. Appendectomy for appendicitis is the most commonly performed emergency operation in the world.

2. Despite the increased use of ultrasonography, computed tomographic scanning, and laparoscopy, the rate of misdiagnosis

of appendicitis has remained constant (15.3%), as has the rate of appendiceal rupture. The percentage of misdiagnosed

cases of appendicitis is significantly higher among women than among men.

3. Appendicitis is a polymicrobial infection, with some series reporting up to 14 different organisms cultured in patients with

perforation. The principal organisms seen in the normal appendix, in acute appendicitis, and in perforated appendicitis are

Escherichia coli and Bacteroides fragilis.

4. Antibiotic prophylaxis is effective in the prevention of postoperative wound infection and intra-abdominal abscess.

Antibiotic coverage is limited to 24 to 48 hours in cases of nonperforated appendicitis. For perforated appendicitis, 7 to 10

days of treatment is recommended.

5. Compared with younger patients, elderly patients with appendicitis often pose a more difficult diagnostic problem because

of the atypical presentation, expanded differential diagnosis, and communication difficulty. These factors contribute to the

disproportionately high perforation rate seen in the elderly.

6. The overall incidence of fetal loss after appendectomy is 4% and the risk of early delivery is 7%. Rates of fetal loss are

considerably higher in women with complex appendicitis than in those with negative appendectomy and those with simple

appendicitis. Removing a normal appendix is associated with a 4% risk of fetal loss and 10% risk of early delivery.

7. Recent data on appendiceal malignancies from the Surveillance, Epidemiology, and End Results program identified

mucinous adenocarcinoma as the most frequent histologic diagnosis, followed by adenocarcinoma, carcinoid, goblet cell

carcinoma, and signet-ring cell carcinoma.

ANATOMY AND FUNCTION

The appendix first becomes visible in the eighth week of embryologic development as a protuberance off the terminal portion

of the cecum. During both antenatal and postnatal development, the growth rate of the cecum exceeds that of the appendix,

so that the appendix is displaced medially toward the ileocecal valve. The relationship of the base of the appendix to the

cecum remains constant, whereas the tip can be found in a retrocecal, pelvic, subcecal, preileal, or right pericolic position

(Fig. 30-1). These anatomic considerations have significant clinical importance in the context of acute appendicitis. The three

taeniae coli converge at the junction of the cecum with the appendix and can be a useful landmark to identify the appendix.

The appendix can vary in length from <1 cm to >30 cm; most appendices are 6 to 9 cm long. Appendiceal absence,

duplication, and diverticula have all been described.1–4

Fig. 30-1.

Various anatomic positions of the vermiform appendix.

For many years, the appendix was erroneously viewed as a vestigial organ with no known function. It is now well recognized

that the appendix is an immunologic organ that actively participates in the secretion of immunoglobulins, particularly

immunoglobulin A. Although there is no clear role for the appendix in the development of human disease, recent studies

demonstrate a potential correlation between appendectomy and the development of inflammatory bowel disease. There

appears to be a negative age-related association between prior appendectomy and subsequent development of ulcerative

colitis. In addition, comparative analysis clearly shows that prior appendectomy is associated with a more benign phenotype

in ulcerative colitis and a delay in onset of disease. The association between Crohn's disease and appendectomy is less clear.

Although earlier studies suggested that appendectomy increases the risk of developing Crohn's disease, more recent studies

that carefully assessed the timing of appendectomy in relation to the onset of Crohn's disease demonstrated a negative

correlation. These data suggest that appendectomy may protect against the subsequent development of inflammatory bowel

disease; however, the mechanism is unclear.4

Lymphoid tissue first appears in the appendix approximately 2 weeks after birth. The amount of lymphoid tissue increases

throughout puberty, remains steady for the next decade, and then begins a steady decrease with age. After the age of 60

years, virtually no lymphoid tissue remains within the appendix, and complete obliteration of the appendiceal lumen is

common.1–4

ACUTE APPENDICITIS

Historical Background

Although ancient texts have scattered descriptions of surgery being undertaken for ailments sounding like appendicitis, credit

for performing the first appendectomy goes to Claudius Amyand, a surgeon at St. George's Hospital in London and Sergeant

Surgeon to Queen Ann, King George I, and King George II. In 1736, he operated on an 11-year-old boy with a scrotal hernia

and a fecal fistula. Within the hernial sac, Amyand found the appendix perforated by a pin. He successfully removed the

appendix and repaired the hernia.5

The appendix was not identified as an organ capable of causing disease until the nineteenth century. In 1824, Louyer-

Villermay presented a paper before the Royal Academy of Medicine in Paris. He reported on two autopsy cases of appendicitis

and emphasized the importance of the condition. In 1827, François Melier, a French physician, expounded on Louyer-

Villermay's work. He reported six autopsy cases and was the first to suggest the antemortem recognition of appendicitis.5

This work was discounted by many physicians of the era, including Baron Guillaume Dupuytren. Dupuytren believed that

inflammation of the cecum was the main cause of pathology of the right lower quadrant. The term typhlitis or perityphlitis

was used to describe right lower quadrant inflammation. In 1839, a textbook authored by Bright and Addison entitled

Elements of Practical Medicine described the symptoms of appendicitis and identified the primary cause of inflammatory

processes of the right lower quadrant.6 Reginald Fitz, a professor of pathologic anatomy at Harvard, is credited with coining

the term appendicitis. His landmark paper definitively identified the appendix as the primary cause of right lower quadrant

inflammation.7

Initial surgical therapy for appendicitis was primarily designed to drain right lower quadrant abscesses that occurred

secondary to appendiceal perforation. It appears that the first surgical treatment for appendicitis or perityphlitis without

abscess was carried out by Hancock in 1848. He incised the peritoneum and drained the right lower quadrant without

removing the appendix. The first published account of appendectomy for appendicitis was by Krönlein in 1886. However, this

patient died 2 days after operation. Fergus, in Canada, performed the first elective appendectomy in 1883.5

The greatest contributor to the advancement in the treatment of appendicitis was Charles McBurney. In 1889, he published

his landmark paper in the New York State Medical Journal describing the indications for early laparotomy for the treatment of

appendicitis. It is in this paper that he described the McBurney point as follows: "maximum tenderness, when one examines

with the fingertips is, in adults, one half to two inches inside the right anterior spinous process of the ilium on a line drawn to

the umbilicus."8 McBurney subsequently published a paper in 1894 describing the incision that bears his name.9 However,

McBurney later credited McArthur with first describing this incision. Semm is widely credited with performing the first

successful laparoscopic appendectomy in 1982.10

The surgical treatment of appendicitis is one of the great public health advances of the last 150 years. Appendectomy for

appendicitis is the most commonly performed emergency operation in the world. Appendicitis is a disease of the young, with

40% of cases occurring in patients between the ages of 10 and 29 years.11 In 1886, Fitz reported the associated mortality

rate of appendicitis to be at least 67% without surgical therapy.7 Currently, the mortality rate for acute appendicitis with

treatment is reported to be <1%.12

Incidence

The lifetime rate of appendectomy is 12% for men and 25% for women, with approximately 7% of all people undergoing

appendectomy for acute appendicitis during their lifetime. Over the 10-year period from 1987 to 1997, the overall

appendectomy rate decreased in parallel with a decrease in incidental appendectomy.11,13 However, the rate of

appendectomy for appendicitis has remained constant at 10 per 10,000 patients per year.14 Appendicitis is most frequently

seen in patients in their second through fourth decades of life, with a mean age of 31.3 years and a median age of 22 years.

There is a slight male:female predominance (1.2 to 1.3:1).11,13

Despite the increased use of ultrasonography, computed tomography (CT), and laparoscopy, the rate of misdiagnosis of

appendicitis has remained constant (15.3%), as has the rate of appendiceal rupture. The percentage of misdiagnosed cases

of appendicitis is significantly higher among women than among men (22.2 vs. 9.3%). The negative appendectomy rate for

women of reproductive age is 23.2%, with the highest rates in women aged 40 to 49 years. The highest negative

appendectomy rate is reported for women >80 years of age (Fig. 30-2).13,14

Fig. 30-2.

Rate of negative appendectomy by age group.

(Adapted from Flum et al.13,14 )

Etiology and Pathogenesis

Obstruction of the lumen is the dominant etiologic factor in acute appendicitis. Fecaliths are the most common cause of

appendiceal obstruction. Less common causes are hypertrophy of lymphoid tissue, inspissated barium from previous x-ray

studies, tumors, vegetable and fruit seeds, and intestinal parasites. The frequency of obstruction rises with the severity of

the inflammatory process. Fecaliths are found in 40% of cases of simple acute appendicitis, in 65% of cases of gangrenous

appendicitis without rupture, and in nearly 90% of cases of gangrenous appendicitis with rupture.

Traditionally the belief has been that there is a predictable sequence of events leading to eventual appendiceal rupture. The

proximal obstruction of the appendiceal lumen produces a closed-loop obstruction, and continuing normal secretion by the

appendiceal mucosa rapidly produces distention. The luminal capacity of the normal appendix is only 0.1 mL. Secretion of as

little as 0.5 mL of fluid distal to an obstruction raises the intraluminal pressure to 60 cm H2O. Distention of the appendix

stimulates the nerve endings of visceral afferent stretch fibers, producing vague, dull, diffuse pain in the midabdomen or

lower epigastrium. Peristalsis also is stimulated by the rather sudden distention, so that some cramping may be

superimposed on the visceral pain early in the course of appendicitis. Distention increases from continued mucosal secretion

and from rapid multiplication of the resident bacteria of the appendix. Distention of this magnitude usually causes reflex

nausea and vomiting, and the diffuse visceral pain becomes more severe. As pressure in the organ increases, venous

pressure is exceeded. Capillaries and venules are occluded, but arteriolar inflow continues, resulting in engorgement and

vascular congestion. The inflammatory process soon involves the serosa of the appendix and in turn parietal peritoneum in

the region, which produces the characteristic shift in pain to the right lower quadrant.

The mucosa of the GI tract, including the appendix, is susceptible to impairment of blood supply; thus its integrity is

compromised early in the process, which allows bacterial invasion. As progressive distention encroaches on first the venous

return and subsequently the arteriolar inflow, the area with the poorest blood supply suffers most: ellipsoidal infarcts develop

in the antimesenteric border. As distention, bacterial invasion, compromise of vascular supply, and infarction progress,

perforation occurs, usually through one of the infarcted areas on the antimesenteric border. Perforation generally occurs just

beyond the point of obstruction rather than at the tip because of the effect of diameter on intraluminal tension.

This sequence is not inevitable, however, and some episodes of acute appendicitis apparently subside spontaneously. Many

patients who are found at operation to have acute appendicitis give a history of previous similar, but less severe, attacks of

right lower quadrant pain. Pathologic examination of the appendices removed from these patients often reveals thickening

and scarring, suggesting old, healed acute inflammation.15,16 The strong association between delay in presentation and

appendiceal perforation supported the proposition that appendiceal perforation is the advanced stage of acute appendicitis;

however, recent epidemiologic studies have suggested that nonperforated and perforated appendicitis may, in fact, be

different diseases.17

Bacteriology

The bacterial population of the normal appendix is similar to that of the normal colon. The appendiceal flora remains

constant throughout life with the exception of Porphyromonas gingivalis. This bacterium is seen only in adults.18 The bacteria

cultured in cases of appendicitis are therefore similar to those seen in other colonic infections such as diverticulitis. The

principal organisms seen in the normal appendix, in acute appendicitis, and in perforated appendicitis are Escherichia coli and

Bacteroides fragilis.18–21 However, a wide variety of both facultative and anaerobic bacteria and mycobacteria may be

present (Table 30-1). Appendicitis is a polymicrobial infection, with some series reporting the culture of up to 14 different

organisms in patients with perforation.18

Table 30-1 Common Organisms Seen in Patients with Acute Appendicitis

Aerobic and Facultative Anaerobic

Gram-negative bacilli Gram-negative bacilli

Escherichia coli Bacteroides fragilis

Pseudomonas aeruginosa Other Bacteroides species

Klebsiella species Fusobacterium species

Gram-positive cocci Gram-positive cocci

Streptococcus anginosus Peptostreptococcus species

Other Streptococcus species Gram-positive bacilli

Enterococcus species Clostridium species

The routine culture of intraperitoneal samples in patients with either perforated or nonperforated appendicitis is questionable.

As discussed earlier, the flora is known, and therefore broad-spectrum antibiotics are indicated. By the time culture results

are available, the patient often has recovered from the illness. In addition, the number of organisms cultured and the ability

of a specific laboratory to culture anaerobic organisms vary greatly. Peritoneal culture should be reserved for patients who

are immunosuppressed, as a result of either illness or medication, and for patients who develop an abscess after the

treatment of appendicitis.20–22 Antibiotic prophylaxis is effective in the prevention of postoperative wound infection and

intra-abdominal abscess.23 Antibiotic coverage is limited to 24 to 48 hours in cases of nonperforated appendicitis. For

perforated appendicitis, 7 to 10 days of therapy is recommended. IV antibiotics are usually given until the white blood cell

count is normal and the patient is afebrile for 24 hours. Antibiotic irrigation of the peritoneal cavity and the use of

transperitoneal drainage through the wound are controversial.24

Clinical Manifestations

SYMPTOMS

Abdominal pain is the prime symptom of acute appendicitis. Classically, pain is initially diffusely centered in the lower

epigastrium or umbilical area, is moderately severe, and is steady, sometimes with intermittent cramping superimposed.

After a period varying from 1 to 12 hours, but usually within 4 to 6 hours, the pain localizes to the right lower quadrant. This

classic pain sequence, although usual, is not invariable. In some patients, the pain of appendicitis begins in the right lower

quadrant and remains there. Variations in the anatomic location of the appendix account for many of the variations in the

principal locus of the somatic phase of the pain. For example, a long appendix with the inflamed tip in the left lower quadrant

causes pain in that area. A retrocecal appendix may cause principally flank or back pain; a pelvic appendix, principally

suprapubic pain; and a retroileal appendix, testicular pain, presumably from irritation of the spermatic artery and ureter.

Intestinal malrotation also is responsible for puzzling pain patterns. The visceral component is in the normal location, but the

somatic component is felt in that part of the abdomen where the cecum has been arrested in rotation.

Anorexia nearly always accompanies appendicitis. It is so constant that the diagnosis should be questioned if the patient is

not anorectic. Although vomiting occurs in nearly 75% of patients, it is neither prominent nor prolonged, and most patients

vomit only once or twice. Vomiting is caused by both neural stimulation and the presence of ileus.

Most patients give a history of obstipation beginning before the onset of abdominal pain, and many feel that defecation

would relieve their abdominal pain. Diarrhea occurs in some patients, however, particularly children, so that the pattern of

bowel function is of little differential diagnostic value.

The sequence of symptom appearance has great significance for the differential diagnosis. In >95% of patients with acute

appendicitis, anorexia is the first symptom, followed by abdominal pain, which is followed, in turn, by vomiting (if vomiting

occurs). If vomiting precedes the onset of pain, the diagnosis of appendicitis should be questioned.

SIGNS

Physical findings are determined principally by what the anatomic position of the inflamed appendix is, as well as by whether

the organ has already ruptured when the patient is first examined.

Vital signs are minimally changed by uncomplicated appendicitis. Temperature elevation is rarely >1°C (1.8°F) and the pulse

rate is normal or slightly elevated. Changes of greater magnitude usually indicate that a complication has occurred or that

another diagnosis should be considered.25

Patients with appendicitis usually prefer to lie supine, with the thighs, particularly the right thigh, drawn up, because any

motion increases pain. If asked to move, they do so slowly and with caution.

The classic right lower quadrant physical signs are present when the inflamed appendix lies in the anterior position.

Tenderness often is maximal at or near the McBurney point.8 Direct rebound tenderness usually is present. In addition,

referred or indirect rebound tenderness is present. This referred tenderness is felt maximally in the right lower quadrant,

which indicates localized peritoneal irritation.25 The Rovsing sign—pain in the right lower quadrant when palpatory pressure

is exerted in the left lower quadrant—also indicates the site of peritoneal irritation. Cutaneous hyperesthesia in the area

supplied by the spinal nerves on the right at T10, T11, and T12 frequently accompanies acute appendicitis. In patients with

obvious appendicitis, this sign is superfluous, but in some early cases, it may be the first positive sign. Hyperesthesia is

elicited either by needle prick or by gently picking up the skin between the forefinger and thumb.

Muscular resistance to palpation of the abdominal wall roughly parallels the severity of the inflammatory process. Early in the

disease, resistance, if present, consists mainly of voluntary guarding. As peritoneal irritation progresses, muscle spasm

increases and becomes largely involuntary, that is, true reflex rigidity due to contraction of muscles directly beneath the

inflamed parietal peritoneum.

Anatomic variations in the position of the inflamed appendix lead to deviations in the usual physical findings. With a

retrocecal appendix, the anterior abdominal findings are less striking, and tenderness may be most marked in the flank.

When the inflamed appendix hangs into the pelvis, abdominal findings may be entirely absent, and the diagnosis may be

missed unless the rectum is examined. As the examining finger exerts pressure on the peritoneum of Douglas' cul-de-sac,

pain is felt in the suprapubic area as well as locally within the rectum. Signs of localized muscle irritation also may be

present. The psoas sign indicates an irritative focus in proximity to that muscle. The test is performed by having the patient

lie on the left side as the examiner slowly extends the patient's right thigh, thus stretching the iliopsoas muscle. The test

result is positive if extension produces pain. Similarly, a positive obturator sign of hypogastric pain on stretching the

obturator internus indicates irritation in the pelvis. The test is performed by passive internal rotation of the flexed right thigh

with the patient supine.

LABORATORY FINDINGS

Mild leukocytosis, ranging from 10,000 to 18,000 cells/mm3, usually is present in patients with acute, uncomplicated

appendicitis and often is accompanied by a moderate polymorphonuclear predominance. White blood cell counts are variable,

however. It is unusual for the white blood cell count to be >18,000 cells/mm3 in uncomplicated appendicitis. White blood cell

counts above this level raise the possibility of a perforated appendix with or without an abscess. Urinalysis can be useful to

rule out the urinary tract as the source of infection. Although several white or red blood cells can be present from ureteral or

bladder irritation as a result of an inflamed appendix, bacteriuria in a urine specimen obtained via catheter generally is not

seen in acute appendicitis.26

Imaging Studies

Plain films of the abdomen, although frequently obtained as part of the general evaluation of a patient with an acute

abdomen, rarely are helpful in diagnosing acute appendicitis. However, plain radiographs can be of significant benefit in ruling

out other pathology. In patients with acute appendicitis, one often sees an abnormal bowel gas pattern, which is a nonspecific

finding. The presence of a fecalith is rarely noted on plain films but, if present, is highly suggestive of the diagnosis. A chest

radiograph is sometimes indicated to rule out referred pain from a right lower lobe pneumonic process.

Additional radiographic studies include barium enema examination and radioactively labeled leukocyte scans. If the appendix

fills on barium enema, appendicitis is excluded. On the other hand, if the appendix does not fill, no determination can be

made.27 To date, there has not been enough experience with radionuclide scans to assess their utility.

Graded compression sonography has been suggested as an accurate way to establish the diagnosis of appendicitis. The

technique is inexpensive, can be performed rapidly, does not require a contrast medium, and can be used even in pregnant

patients. Sonographically, the appendix is identified as a blind-ending, nonperistaltic bowel loop originating from the cecum.

With maximal compression, the diameter of the appendix is measured in the anteroposterior dimension. Scan results are

considered positive if a noncompressible appendix ≥6 mm in the anteroposterior direction is demonstrated (Fig. 30-3). The

presence of an appendicolith establishes the diagnosis. Thickening of the appendiceal wall and the presence of

periappendiceal fluid is highly suggestive. Sonographic demonstration of a normal appendix, which is an easily compressible,

blind-ending tubular structure measuring ≤5 mm in diameter, excludes the diagnosis of acute appendicitis. The study results

are considered inconclusive if the appendix is not visualized and there is no pericecal fluid or mass. When the diagnosis of

acute appendicitis is excluded by sonography, a brief survey of the remainder of the abdominal cavity should be performed to

establish an alternative diagnosis. In females of childbearing age, the pelvic organs must be adequately visualized either by

transabdominal or endovaginal ultrasonography to exclude gynecologic pathology as a cause of acute abdominal pain. The

sonographic diagnosis of acute appendicitis has a reported sensitivity of 55 to 96% and a specificity of 85 to 98%.28–30

Sonography is similarly effective in children and pregnant women, although its application is somewhat limited in late

pregnancy.

Fig. 30-3.

Sonogram of a 10-year-old girl who presented with nausea, vomiting, and abdominal pain. The appendix measured 10.0 mm in maximal anteroposterior diameter in both the noncompression (A) and compression (B) views.

Although sonography can easily identify abscesses in cases of perforation, the technique has limitations and results are user

dependent. A false-positive scan result can occur in the presence of periappendicitis from surrounding inflammation, a

dilated fallopian tube can be mistaken for an inflamed appendix, inspissated stool can mimic an appendicolith, and, in obese

patients, the appendix may not be compressible because of overlying fat. False-negative sonogram results can occur if

appendicitis is confined to the appendiceal tip, the appendix is retrocecal, the appendix is markedly enlarged and mistaken

for small bowel, or the appendix is perforated and therefore compressible.31

Some studies have reported that graded compression sonography improved the diagnosis of appendicitis over clinical

examination, specifically decreasing the percentage of negative explorations for appendectomies from 37 to 13%.32

Sonography also decreases the time before operation. Sonography identified appendicitis in 10% of patients who were

believed to have a low likelihood of the disease on physical examination.33 The positive and negative predictive values of

ultrasonography have impressively been reported as 91 and 92%, respectively. However, in a recent prospective multicenter

study, routine ultrasonography did not improve diagnostic accuracy or rates of negative appendectomy or perforation

compared with clinical assessment.

High-resolution helical CT also has been used to diagnose appendicitis. On CT scan, the inflamed appendix appears dilated

(>5 cm) and the wall is thickened. There is usually evidence of inflammation, with "dirty fat," thickened mesoappendix, and

even an obvious phlegmon (Fig. 30-4). Fecaliths can be easily visualized, but their presence is not necessarily

pathognomonic of appendicitis. An important suggestive abnormality is the arrowhead sign. This is caused by thickening of

the cecum, which funnels contrast agent toward the orifice of the inflamed appendix. CT scanning is also an excellent

technique for identifying other inflammatory processes masquerading as appendicitis.

Fig. 30-4.

Computed tomographic scans with findings positive for appendicitis. Note the thick-walled and dilated appendix (A) and mesenteric streaking and "dirty fat" (B).

Several CT techniques have been used, including focused and nonfocused CT scans and enhanced and nonenhanced helical

CT scanning. Nonenhanced helical CT scanning is important, because one of the disadvantages of using CT scanning in the

evaluation of right lower quadrant pain is dye allergy. Surprisingly, all of these techniques have yielded essentially identical

rates of diagnostic accuracy: 92 to 97% sensitivity, 85 to 94% specificity, 90 to 98% accuracy, and 75 to 95% positive and

95 to 99% negative predictive values.34–36 The additional use of a rectally administered contrast agent did not improve the

results of CT scanning.

A number of studies have documented improvement in diagnostic accuracy with the liberal use of CT scanning in the work-up

of suspected appendicitis. CT lowered the rate of negative appendectomies from 19 to 12% in one study,37 and the

incidence of negative appendectomies in women from 24 to 5% in another.38 The use of this imaging study altered the care

of 24% of patients studied and provided alternative diagnoses in half of the patients with normal appendices on CT scan.39

Despite the potential usefulness of this technique, there are significant disadvantages. CT scanning is expensive, exposes the

patient to significant radiation, and cannot be used during pregnancy. Allergy contraindicates the administration of IV

contrast agents in some patients, and others cannot tolerate the oral ingestion of luminal dye, particularly in the presence of

nausea and vomiting. Finally, not all studies have documented the utility of CT scanning in all patients with right lower

quadrant pain.40

A number of studies have compared the effectiveness of graded compression sonography and helical CT in establishing the

diagnosis of appendicitis. Although the differences are rather small, CT scanning has consistently proven superior. For

example, in one study, 600 ultrasounds and 317 CT scans demonstrated sensitivity of 80 and 97%, specificity of 93 and

94%, diagnostic accuracy of 89 and 95%, positive predictive value of 91 and 92%, and negative predictive value of 88 and

98%, respectively.30 In another study, ultrasound positively impacted the management of 19% of patients, compared with

73% of patients for CT. Finally, in a third study, the negative appendix rate was 17% for patients studied by ultrasonography

compared with a negative appendix rate of 2% for patients who underwent helical CT scanning.41 One concern about

ultrasonography is the high intraobserver variability.42

One issue that has not been resolved is which patients are candidates for imaging studies.43 This question may be moot,

because CT scanning routinely is ordered by emergency physicians before surgeons are even consulted. The concept that all

patients with right lower quadrant pain should undergo CT scanning has been strongly supported by two reports by Rao and

his colleagues at the Massachusetts General Hospital. In one, this group documented that CT scanning led to a fall in the

negative appendectomy rate from 20 to 7% and a decline in the perforation rate from 22 to 14%, as well as establishment of

an alternative diagnosis in 50% of patients.44 In the second study, published in the New England Journal of Medicine, Rao

and associates documented that CT scanning prevented 13 unnecessary appendectomies, saved 50 inpatient hospital days,

and lowered the per-patient cost by $447.45 In contrast, several other studies failed to prove an advantage of routine CT

scanning, documenting that surgeon accuracy approached that of the imaging study and expressing concern that the

imaging studies could adversely delay appendectomy in affected patients.46,47

The rational approach is the selective use of CT scanning. This has been documented by several studies in which imaging was

performed based on an algorithm or protocol.48 The likelihood of appendicitis can be ascertained using the Alvarado scale

(Table 30-2).49 This scoring system was designed to improve the diagnosis of appendicitis and was devised by giving

relative weight to specific clinical manifestation. Table 30-2 lists the eight specific indicators identified. Patients with scores of

9 or 10 are almost certain to have appendicitis; there is little advantage in further work-up, and they should go to the

operating room. Patients with scores of 7 or 8 have a high likelihood of appendicitis, whereas scores of 5 or 6 are compatible

with, but not diagnostic of, appendicitis. CT scanning is certainly appropriate for patients with Alvarado scores of 5 and 6, and

a case can be built for imaging for those with scores of 7 and 8. On the other hand, it is difficult to justify the expense,

radiation exposure, and possible complications of CT scanning in patients whose scores of 0 to 4 make it extremely unlikely

(but not impossible) that they have appendicitis.

Table 30-2 Alvarado Scale for the Diagnosis of Appendicitis

Manifestations Value

Symptoms Migration of pain 1

Anorexia 1

Nausea and/or vomiting 1

Signs Right lower quadrant tenderness 2

Rebound 1

Elevated temperature 1

Laboratory values Leukocytosis 2

Left shift in leukocyte count 1

Total points 10

Source: Reproduced with permission from Alvarado.49

Selective CT scanning based on the likelihood of appendicitis takes advantage of the clinical skill of the experienced surgeon

and, when indicated, adds the expertise of the radiologist and his or her imaging study. Figure 30-5 proposes a treatment

algorithm addressing the rational use of diagnostic testing.50

Fig. 30-5.

Clinical algorithm for suspected cases of acute appendicitis. If gynecologic disease is suspected, a pelvic and endovaginal ultrasound examination is indicated.

(Reproduced with permission from Paulson et al.50 Copyright © Massachusetts Medical Society. All rights reserved.)

Laparoscopy can serve as both a diagnostic and therapeutic maneuver for patients with acute abdominal pain and suspected

acute appendicitis. Laparoscopy is probably most useful in the evaluation of females with lower abdominal complaints,

because appendectomy is performed on a normal appendix in as many as 30 to 40% of these patients. Differentiating acute

gynecologic pathology from acute appendicitis can be effectively accomplished using the laparoscope.

Appendiceal Rupture

Immediate appendectomy has long been the recommended treatment for acute appendicitis because of the presumed risk of

progression to rupture. The overall rate of perforated appendicitis is 25.8%. Children <5 years of age and patients >65 years

of age have the highest rates of perforation (45 and 51%, respectively) (Fig. 30-6).14,15,51 It has been suggested that

delays in presentation are responsible for the majority of perforated appendices. There is no accurate way of determining

when and if an appendix will rupture before resolution of the inflammatory process. Recent studies suggest that, in selected

patients, observation and antibiotic therapy alone may be an appropriate treatment for acute appendicitis.17,52

Fig. 30-6.

Rate of appendiceal rupture by age group.

(Personal communication from David Flum, MD.)

Appendiceal rupture occurs most frequently distal to the point of luminal obstruction along the antimesenteric border of the

appendix. Rupture should be suspected in the presence of fever with a temperature of >39°C (102°F) and a white blood cell

count of >18,000 cells/mm3. In the majority of cases, rupture is contained and patients display localized rebound

tenderness. Generalized peritonitis will be present if the walling-off process is ineffective in containing the rupture.

In 2 to 6% of cases, an ill-defined mass is detected on physical examination. This could represent a phlegmon, which

consists of matted loops of bowel adherent to the adjacent inflamed appendix, or a periappendiceal abscess. Patients who

present with a mass have experienced symptoms for a longer duration, usually at least 5 to 7 days. Distinguishing acute,

uncomplicated appendicitis from acute appendicitis with perforation on the basis of clinical findings is often difficult, but it is

important to make the distinction because their treatment differs. CT scan may be beneficial in guiding therapy. Phlegmons

and small abscesses can be treated conservatively with IV antibiotics; well-localized abscesses can be managed with

percutaneous drainage; complex abscesses should be considered for surgical drainage. If operative drainage is required, it

should be performed using an extraperitoneal approach, with appendectomy reserved for cases in which the appendix is

easily accessible. Interval appendectomy performed at least 6 weeks after the acute event has classically been recommended

for all patients treated either nonoperatively or with simple drainage of an abscess.53,54

Differential Diagnosis

The differential diagnosis of acute appendicitis is essentially the diagnosis of the acute abdomen (see Chap. 35). This is

because clinical manifestations are not specific for a given disease but are specific for disturbance of a given physiologic

function or functions. Thus, an essentially identical clinical picture can result from a wide variety of acute processes within

the peritoneal cavity that produce the same alterations of function as does acute appendicitis.

The accuracy of preoperative diagnosis should be approximately 85%. If it is consistently less, it is likely that some

unnecessary operations are being performed, and a more rigorous preoperative differential diagnosis is in order. A diagnostic

accuracy rate that is consistently >90% should also cause concern, because this may mean that some patients with atypical,

but bona fide, cases of acute appendicitis are being "observed" when they should receive prompt surgical intervention. The

Haller group, however, has shown that this is not invariably true.55 Before that group's study, the perforation rate at the

hospital at which the study took place was 26.7%, and acute appendicitis was found in 80% of the patients undergoing

operation. By implementing a policy of intensive inhospital observation when the diagnosis of appendicitis was unclear, the

group raised the rate of acute appendicitis found at operation to 94%, but the perforation rate remained unchanged at

27.5%.55 The rate of false-negative appendectomies is highest in young adult females. A normal appendix is found in 32 to

45% of appendectomies performed in women 15 to 45 years of age.14

A common error is to make a preoperative diagnosis of acute appendicitis only to find some other condition (or nothing) at

operation. Much less frequently, acute appendicitis is found after a preoperative diagnosis of another condition. The most

common erroneous preoperative diagnoses—together accounting for >75% of cases—are, in descending order of frequency,

acute mesenteric lymphadenitis, no organic pathologic condition, acute pelvic inflammatory disease, twisted ovarian cyst or

ruptured graafian follicle, and acute gastroenteritis.

The differential diagnosis of acute appendicitis depends on four major factors: the anatomic location of the inflamed

appendix; the stage of the process (i.e., simple or ruptured); the patient's age; and the patient's sex.56–60

ACUTE MESENTERIC ADENITIS

Acute mesenteric adenitis is the disease most often confused with acute appendicitis in children. Almost invariably, an upper

respiratory tract infection is present or has recently subsided. The pain usually is diffuse, and tenderness is not as sharply

localized as in appendicitis. Voluntary guarding is sometimes present, but true rigidity is rare. Generalized lymphadenopathy

may be noted. Laboratory procedures are of little help in arriving at the correct diagnosis, although a relative lymphocytosis,

when present, suggests mesenteric adenitis. Observation for several hours is in order if the diagnosis of mesenteric adenitis

seems likely, because it is a self-limited disease. However, if the differentiation remains in doubt, immediate exploration is

the safest course of action.

Human infection with Yersinia enterocolitica or Yersinia pseudotuberculosis, transmitted through food contaminated by feces

or urine, causes mesenteric adenitis as well as ileitis, colitis, and acute appendicitis. Many of the infections are mild and self

limited, but they may lead to systemic disease with a high fatality rate if untreated. The organisms are usually sensitive to

tetracyclines, streptomycin, ampicillin, and kanamycin. A preoperative suspicion of the diagnosis should not delay operative

intervention, because appendicitis caused by Yersinia cannot be clinically distinguished from appendicitis due to other

causes. Approximately 6% of cases of mesenteric adenitis are caused by Yersinia infection.

Salmonella typhimurium infection causes mesenteric adenitis and paralytic ileus with symptoms similar to those of

appendicitis. The diagnosis can be established by serologic testing. Campylobacter jejuni causes diarrhea and pain that

mimics that of appendicitis. The organism can be cultured from stool.

GYNECOLOGIC DISORDERS

Diseases of the female internal reproductive organs that may erroneously be diagnosed as appendicitis are, in approximate

descending order of frequency, pelvic inflammatory disease, ruptured graafian follicle, twisted ovarian cyst or tumor,

endometriosis, and ruptured ectopic pregnancy.

Pelvic Inflammatory Disease

In pelvic inflammatory disease the infection usually is bilateral but, if confined to the right tube, may mimic acute

appendicitis. Nausea and vomiting are present in patients with appendicitis, but in only approximately 50% of those with

pelvic inflammatory disease. Pain and tenderness are usually lower, and motion of the cervix is exquisitely painful.

Intracellular diplococci may be demonstrable on smear of the purulent vaginal discharge. The ratio of cases of appendicitis to

cases of pelvic inflammatory disease is low in females in the early phase of the menstrual cycle and high during the luteal

phase. The careful clinical use of these features has reduced the incidence of negative findings on laparoscopy in young

women to 15%.

Ruptured Graafian Follicle

Ovulation commonly results in the spillage of sufficient amounts of blood and follicular fluid to produce brief, mild lower

abdominal pain. If the amount of fluid is unusually copious and is from the right ovary, appendicitis may be simulated. Pain

and tenderness are rather diffuse. Leukocytosis and fever are minimal or absent. Because this pain occurs at the midpoint of

the menstrual cycle, it is often called mittelschmerz.

Twisted Ovarian Cyst

Serous cysts of the ovary are common and generally remain asymptomatic. When right-sided cysts rupture or undergo

torsion, the manifestations are similar to those of appendicitis. Patients develop right lower quadrant pain, tenderness,

rebound, fever, and leukocytosis. If the mass is palpable on physical examination, the diagnosis can be made easily. Both

transvaginal ultrasonography and CT scanning can be diagnostic if a mass is not palpable.

Torsion requires emergent operative treatment. If the torsion is complete or longstanding, the pedicle undergoes thrombosis,

and the ovary and tube become gangrenous and require resection. Leakage of ovarian cysts resolves spontaneously,

however, and is best treated nonoperatively.24,56–61

Ruptured Ectopic Pregnancy

Blastocysts may implant in the fallopian tube (usually the ampullary portion) and in the ovary. Rupture of right tubal or

ovarian pregnancies can mimic appendicitis. Patients may give a history of abnormal menses, either missing one or two

periods or noting only slight vaginal bleeding. Unfortunately, patients do not always realize they are pregnant. The

development of right lower quadrant or pelvic pain may be the first symptom. The diagnosis of ruptured ectopic pregnancy

should be relatively easy. The presence of a pelvic mass and elevated levels of chorionic gonadotropin are characteristic.

Although the leukocyte count rises slightly (to approximately 14,000 cells/mm3), the hematocrit level falls as a consequence

of the intra-abdominal hemorrhage. Vaginal examination reveals cervical motion and adnexal tenderness, and a more

definitive diagnosis can be established by culdocentesis. The presence of blood and particularly decidual tissue is

pathognomonic. The treatment of ruptured ectopic pregnancy is emergency surgery.

ACUTE GASTROENTERITIS

Acute gastroenteritis is common but usually can be easily distinguished from acute appendicitis. Gastroenteritis is

characterized by profuse diarrhea, nausea, and vomiting. Hyperperistaltic abdominal cramps precede the watery stools. The

abdomen is relaxed between cramps, and there are no localizing signs. Laboratory values vary with the specific cause.

OTHER INTESTINAL DISORDERS

Meckel's Diverticulitis

Meckel's diverticulitis gives rise to a clinical picture similar to that of acute appendicitis. Meckel's diverticulum is located

within the distal 2 ft of the ileum. Meckel's diverticulitis is associated with the same complications as appendicitis and

requires the same treatment—prompt surgical intervention. Resection of the segment of ileum bearing the diverticulum with

end-to-end anastomosis can nearly always be done through a McBurney incision, extended if necessary, or laparoscopically.

Crohn's Enteritis

The manifestations of acute regional enteritis—fever, right lower quadrant pain and tenderness, and leukocytosis—often

simulate acute appendicitis. The presence of diarrhea and the absence of anorexia, nausea, and vomiting favor a diagnosis of

enteritis, but this is not sufficient to exclude acute appendicitis. In an appreciable percentage of patients with chronic regional

enteritis, the diagnosis is first made at the time of operation for presumed acute appendicitis. In cases of an acutely inflamed

distal ileum with no cecal involvement and a normal appendix, appendectomy is indicated. Progression to chronic Crohn's

ileitis is uncommon.

Colonic Lesions

Diverticulitis or perforating carcinoma of the cecum, or of that portion of the sigmoid that lies in the right side, may be

impossible to distinguish from appendicitis. These entities should be considered in older patients. CT scanning is often helpful

in making a diagnosis in older patients with right lower quadrant pain and atypical clinical presentations.

Epiploic appendagitis probably results from infarction of the colonic appendage(s) secondary to torsion. Symptoms may be

minimal, or there may be continuous abdominal pain in an area corresponding to the contour of the colon, lasting several

days. Pain shift is unusual, and there is no diagnostic sequence of symptoms. The patient does not look ill, nausea and

vomiting are unusual, and appetite generally is unaffected. Localized tenderness over the site is usual and often is associated

with rebound without rigidity. In 25% of reported cases, pain persists or recurs until the infarcted epiploic appendage is

removed.

OTHER DISEASES

Diseases or conditions not mentioned in the preceding sections that must be considered in the differential diagnosis include

foreign body perforations of the bowel, closed-loop intestinal obstruction, mesenteric vascular infarction, pleuritis of the right

lower chest, acute cholecystitis, acute pancreatitis, hematoma of the abdominal wall, epididymitis, testicular torsion, urinary

tract infection, ureteral stone, primary peritonitis, and Henoch-Schönlein purpura.

Acute Appendicitis in the Young

The establishment of a diagnosis of acute appendicitis is more difficult in young children than in the adult. The inability of

young children to give an accurate history, diagnostic delays by both parents and physicians, and the frequency of GI upset

in children are all contributing factors.62 In children the physical examination findings of maximal tenderness in the right

lower quadrant, the inability to walk or walking with a limp, and pain with percussion, coughing, and hopping were found to

have the highest sensitivity for appendicitis.63

The more rapid progression to rupture and the inability of the underdeveloped greater omentum to contain a rupture lead to

significant morbidity rates in children. Children <5 years of age have a negative appendectomy rate of 25% and an

appendiceal perforation rate of 45%. These rates may be compared with a negative appendectomy rate of <10% and a

perforated appendix rate of 20% for children 5 to 12 years of age.13,14 The incidence of major complications after

appendectomy in children is correlated with appendiceal rupture. The wound infection rate after the treatment of

nonperforated appendicitis in children is 2.8% compared with a rate of 11% after the treatment of perforated appendicitis.

The incidence of intra-abdominal abscess also is higher after the treatment of perforated appendicitis than after

nonperforated appendicitis (6% vs. 3%).23 The treatment regimen for perforated appendicitis generally includes immediate

appendectomy and irrigation of the peritoneal cavity. Antibiotic coverage is limited to 24 to 48 hours in cases of

nonperforated appendicitis. For perforated appendicitis IV antibiotics usually are given until the white blood cell count is

normal and the patient is afebrile for 24 hours. The use of antibiotic irrigation of the peritoneal cavity and transperitoneal

drainage through the wound are controversial. Laparoscopic appendectomy has been shown to be safe and effective for the

treatment of appendicitis in children.64

Acute Appendicitis in the Elderly

Compared with younger patients, elderly patients with appendicitis often pose a more difficult diagnostic problem because of

the atypical presentation, expanded differential diagnosis, and communication difficulty. These factors may be responsible for

the disproportionately high perforation rate seen in the elderly. In the general population, perforation rates range from 20 to

30%, compared with 50 to 70% in the elderly.65 In addition, the perforation rate appears to increase with age >80 years.66

Elderly patients usually present with lower abdominal pain, but on clinical examination, localized right lower quadrant

tenderness is present in only 80 to 90% of patients. A history of periumbilical pain migrating to the right lower quadrant is

reported infrequently. The usefulness of the Alvarado score appears to decline in the elderly. Fewer then 50% of the elderly

with appendicitis have an Alvarado score of ≥7.66 Although currently there are no criteria that definitively identify elderly

patients with acute appendicitis who are at risk of rupture, prioritization should be given to patients with a temperature of

>38°C (100.4°F) and a shift to the left in leukocyte count of >76%, especially if they are male, are anorectic, or have had

pain of long duration before admission.65

As a result of increased comorbidities and an increased rate of perforation, postoperative morbidity, mortality, and hospital

length of stay are increased in the elderly compared with younger populations with appendicitis. Although no randomized

trials have been conducted, it appears that elderly patients benefit from a laparoscopic approach to treatment of

appendicitis. The use of laparoscopy in the elderly has significantly increased in recent years. In general, laparoscopic

appendectomy offers elderly patients with appendicitis a shorter length of hospital stay, a reduction in complication and

mortality rates, and a greater chance of discharge to home (independent of further nursing care or rehabilitation).67

Acute Appendicitis during Pregnancy

Appendectomy for presumed appendicitis is the most common surgical emergency during pregnancy. The incidence is

approximately 1 in 766 births. Acute appendicitis can occur at any time during pregnancy.68 The overall negative

appendectomy rate during pregnancy is approximately 25% and appears to be higher than the rate seen in nonpregnant

women.68,69 A higher rate of negative appendectomy is seen in the second trimester, and the lowest rate is in the third

trimester. The diversity of clinical presentations and the difficulty in making the diagnosis of acute appendicitis in pregnant

women is well established. This is particularly true in the late second trimester and the third trimester, when many

abdominal symptoms may be considered pregnancy related. In addition, during pregnancy there are anatomic changes in the

appendix (Fig. 30-7) and increased abdominal laxity that may further complicate clinical evaluation. There is no association

between appendectomy and subsequent fertility.

Fig. 30-7.

Location of the appendix during pregnancy. ASIS = anterior superior iliac spine.

[Reproduced with permission from Metcalf A: The appendix, in Corson JD, Williamson RCN (eds): Surgery. London: Mosby,2001.]

Appendicitis in pregnancy should be suspected when a pregnant woman complains of abdominal pain of new onset. The most

consistent sign encountered in acute appendicitis during pregnancy is pain in the right side of the abdomen. Seventy-four

percent of patients report pain located in the right lower abdominal quadrant, with no difference between early and late

pregnancy. Only 57% of patients present with the classic history of diffuse periumbilical pain migrating to the right lower

quadrant. Laboratory evaluation is not helpful in establishing the diagnosis of acute appendicitis during pregnancy. The

physiologic leukocytosis of pregnancy has been defined as high as 16,000 cells/mm3. In one series only 38% of patients with

appendicitis had a white blood cell count of >16,000 cells/mm3.68 Recent data suggest that the incidence of perforated or

complex appendicitis is not increased in pregnant patients.69

When the diagnosis is in doubt, abdominal ultrasound may be beneficial. Another option is magnetic resonance imaging,

which has no known deleterious effects on the fetus. The American College of Radiology recommends the use of nonionizing

radiation techniques for front-line imaging in pregnant women.70 Laparoscopy has been advocated in equivocal cases,

especially early in pregnancy; however laparoscopic appendectomy may be associated with an increase in pregnancy-related

complications. In an analysis of outcomes in California using administrative databases, laparoscopy was found to be

associated with a 2.31 increased odds of fetal loss over open surgery.69

The overall incidence of fetal loss after appendectomy is 4% and the risk of early delivery is 7%. Rates of fetal loss are

considerably higher in women with complex appendicitis than in those with a negative appendectomy and with simple

appendicitis. It is important to note that a negative appendectomy is not a benign procedure. Removing a normal appendix is

associated with a 4% risk of fetal loss and 10% risk of early delivery. Maternal mortality after appendectomy is extremely rare

(0.03%). Because the incidence of ruptured appendix is similar in pregnant and nonpregnant women and because maternal

mortality is so low, it appears that the greatest opportunity to improve fetal outcomes is by improving diagnostic accuracy

and reducing the rate of negative appendectomy.68–71

Appendicitis in Patients with AIDS or HIV Infection

The incidence of acute appendicitis in HIV-infected patients is reported to be 0.5%. This is higher than the 0.1 to 0.2%

incidence reported for the general population.72 The presentation of acute appendicitis in HIV-infected patients is similar to

that in noninfected patients. The majority of HIV-infected patients with appendicitis have fever, periumbilical pain radiating

to the right lower quadrant (91%), right lower quadrant tenderness (91%), and rebound tenderness (74%). HIV-infected

patients do not manifest an absolute leukocytosis; however, if a baseline leukocyte count is available, nearly all HIV-infected

patients with appendicitis demonstrate a relative leukocytosis.72,73

The risk of appendiceal rupture appears to be increased in HIV-infected patients. In one large series of HIV-infected patients

who underwent appendectomy for presumed appendicitis, 43% of patients were found to have perforated appendicitis at

laparotomy.74 The increased risk of appendiceal rupture may be related to the delay in presentation seen in this patient

population.72,74 The mean duration of symptoms before arrival in the emergency department has been reported to be

increased in HIV-infected patients, with >60% of patients reporting the duration of symptoms to be longer than 24 hours.72

In early series, significant hospital delay also may have contributed to high rates of rupture.72 However, with increased

understanding of abdominal pain in HIV-infected patients, hospital delay has become less prevalent.72,75 A low CD4 count is

also associated with an increased incidence of appendiceal rupture. In one large series, patients with nonruptured appendices

had CD4 counts of 158.75 ± 47 cells/mm3 compared with 94.5 ± 32 cells/mm3 in patients with appendiceal rupture.72

The differential diagnosis of right lower quadrant pain is expanded in HIV-infected patients compared with the general

population. In addition to the conditions discussed elsewhere in this chapter, opportunistic infections should be considered as

a possible cause of right lower quadrant pain.72–75 Such opportunistic infections include cytomegalovirus (CMV) infection,

Kaposi's sarcoma, tuberculosis, lymphoma, and other causes of infectious colitis. CMV infection may be seen anywhere in the

GI tract. CMV infection causes a vasculitis of blood vessels in the submucosa of the gut, which leads to thrombosis. Mucosal

ischemia develops, leading to ulceration, gangrene of the bowel wall, and perforation. Spontaneous peritonitis may be caused

by opportunistic pathogens, including CMV, Mycobacterium avium-intracellulare complex, Mycobacterium tuberculosis,

Cryptococcus neoformans, and Strongyloides. Kaposi's sarcoma and non-Hodgkin's lymphoma may present with pain and a

right lower quadrant mass. Viral and bacterial colitis occur with a higher frequency in HIV-infected patients than in the

general population. Colitis should always be considered in HIV-infected patients presenting with right lower quadrant pain.

Neutropenic enterocolitis (typhlitis) should also be considered in the differential diagnosis of right lower quadrant pain in HIV-

infected patients.73,75

A thorough history and physical examination is important when evaluating any patient with right lower quadrant pain. In the

HIV-infected patient with classic signs and symptoms of appendicitis, immediate appendectomy is indicated. In those patients

with diarrhea as a prominent symptom, colonoscopy may be warranted. In patients with equivocal findings, CT scan is

usually helpful. The majority of pathologic findings identified in HIV-infected patients who undergo appendectomy for

presumed appendicitis are typical. The negative appendectomy rate is 5 to 10%. However, in up to 25% of patients AIDS-

related entities are found in the operative specimens, including CMV, Kaposi's sarcoma, and M. avium-intracellulare

complex.72,74

In a retrospective study of 77 HIV-infected patients from 1988 to 1995, the 30-day mortality rate for patients undergoing

appendectomy was reported to be 9.1%.72 More recent series report 0% mortality in this group of patients.75 Morbidity rates

for HIV-infected patients with nonperforated appendicitis are similar to those seen in the general population. Postoperative

morbidity rates appear to be higher in HIV-infected patients with perforated appendicitis. In addition, the length of hospital

stay for HIV-infected patients undergoing appendectomy is twice that for the general population.72,75 No series has been

reported to date that addresses the role of laparoscopic appendectomy in the HIV-infected population.

Treatment

Despite the advent of more sophisticated diagnostic modalities, the importance of early operative intervention should not be

minimized. Once the decision to operate for presumed acute appendicitis has been made, the patient should be prepared for

the operating room. Adequate hydration should be ensured, electrolyte abnormalities should be corrected, and pre-existing

cardiac, pulmonary, and renal conditions should be addressed. A large meta-analysis has demonstrated the efficacy of

preoperative antibiotics in lowering the infectious complications in appendicitis.23 Most surgeons routinely administer

antibiotics to all patients with suspected appendicitis. If simple acute appendicitis is encountered, there is no benefit in

extending antibiotic coverage beyond 24 hours. If perforated or gangrenous appendicitis is found, antibiotics are continued

until the patient is afebrile and has a normal white blood cell count. For intra-abdominal infections of GI tract origin that are

of mild to moderate severity, the Surgical Infection Society has recommended single-agent therapy with cefoxitin, cefotetan,

or ticarcillin-clavulanic acid. For more severe infections, single-agent therapy with carbapenems or combination therapy with

a third-generation cephalosporin, monobactam, or aminoglycoside plus anaerobic coverage with clindamycin or

metronidazole is indicated.24 The recommendations are similar for children.76

OPEN APPENDECTOMY

For open appendectomy most surgeons use either a McBurney (oblique) or Rocky-Davis (transverse) right lower quadrant

muscle-splitting incision in patients with suspected appendicitis. The incision should be centered over either the point of

maximal tenderness or a palpable mass. If an abscess is suspected, a laterally placed incision is imperative to allow

retroperitoneal drainage and to avoid generalized contamination of the peritoneal cavity. If the diagnosis is in doubt, a lower

midline incision is recommended to allow a more extensive examination of the peritoneal cavity. This is especially relevant in

older patients with possible malignancy or diverticulitis.

Several techniques can be used to locate the appendix. Because the cecum usually is visible within the incision, the

convergence of the taeniae can be followed to the base of the appendix. A sweeping lateral to medial motion can aid in

delivering the appendiceal tip into the operative field. Occasionally, limited mobilization of the cecum is needed to aid in

adequate visualization. Once identified, the appendix is mobilized by dividing the mesoappendix, with care taken to ligate the

appendiceal artery securely.

The appendiceal stump can be managed by simple ligation or by ligation and inversion with either a purse-string or Z stitch.

As long as the stump is clearly viable and the base of the cecum is not involved with the inflammatory process, the stump

can be safely ligated with a nonabsorbable suture. The mucosa is frequently obliterated to avoid the development of

mucocele. The peritoneal cavity is irrigated and the wound closed in layers. If perforation or gangrene is found in adults, the

skin and subcutaneous tissue should be left open and allowed to heal by secondary intent or closed in 4 to 5 days as a

delayed primary closure. In children, who generally have little subcutaneous fat, primary wound closure has not led to an

increased incidence of wound infection.

If appendicitis is not found, a methodical search must be made for an alternative diagnosis. The cecum and mesentery should

first be inspected. Next, the small bowel should be examined in a retrograde fashion beginning at the ileocecal valve and

extending at least 2 ft. In females, special attention should be paid to the pelvic organs. An attempt also should be made to

examine the upper abdominal contents. Peritoneal fluid should be sent for Gram's staining and culture. If purulent fluid is

encountered, it is imperative that the source be identified. A medial extension of the incision (Fowler-Weir), with division of

the anterior and posterior rectus sheath, is acceptable if further evaluation of the lower abdomen is indicated. If upper

abdominal pathology is encountered, the right lower quadrant incision is closed and an appropriate upper midline incision is

made.9

LAPAROSCOPIC APPENDECTOMY

Semm first reported successful laparoscopic appendectomy several years before the first laparoscopic cholecystectomy.10

However, the laparoscopic approach to appendectomy did not come into widespread use until after the success of

laparoscopic cholecystectomy. This may be due to the fact that appendectomy, by virtue of its small incision, is already a

form of minimal-access surgery.77

Laparoscopic appendectomy is performed under general anesthesia. A nasogastric tube and a urinary catheter are placed

before obtaining a pneumoperitoneum. Laparoscopic appendectomy usually requires the use of three ports. Four ports may

occasionally be necessary to mobilize a retrocecal appendix. The surgeon usually stands to the patient's left. One assistant is

required to operate the camera. One trocar is placed in the umbilicus (10 mm), and a second trocar is placed in the

suprapubic position. Some surgeons place this second port in the left lower quadrant. The suprapubic trocar is either 10 or

12 mm, depending on whether or not a linear stapler will be used. The placement of the third trocar (5 mm) is variable and

usually is either in the left lower quadrant, epigastrium, or right upper quadrant. Placement is based on location of the

appendix and surgeon preference. Initially, the abdomen is thoroughly explored to exclude other pathology. The appendix is

identified by following the anterior taeniae to its base. Dissection at the base of the appendix enables the surgeon to create a

window between the mesentery and the base of the appendix (Fig. 30-8A). The mesentery and base of the appendix are

then secured and divided separately. When the mesoappendix is involved with the inflammatory process, it is often best to

divide the appendix first with a linear stapler and then to divide the mesoappendix immediately adjacent to the appendix

with clips, electrocautery, Harmonic Scalpel, or staples (Fig. 30-8B and 30-8C). The base of the appendix is not inverted. The

appendix is removed from the abdominal cavity through a trocar site or within a retrieval bag. The base of the appendix and

the mesoappendix should be evaluated for hemostasis. The right lower quadrant should be irrigated. Trocars are

removed under direct vision.78,79

Fig. 30-8.

Laparoscopic resection of the appendix. Occasionally, if the appendix and mesoappendix are extremely inflamed, it is easier to divide the appendix at its base before division of the mesoappendix. A. A window is created in the mesoappendix closeto the base of the appendix. B. The linear stapler is then used to divide the appendix at its base. C. Finally the mesoappendix can be easily divided using the linear stapler.

[Reproduced with permission from Ortega JM, Ricardo AE: Surgery of the appendix and colon, in Moody FG (ed): Atlas ofAmbulatory Surgery. Philadelphia: WB Saunders, 1999.]

The utility of laparoscopic appendectomy in the management of acute appendicitis remains controversial. Surgeons may be

hesitant to implement a new technique because the conventional open approach already has proved to be simple and

effective. A number of articles in peer-reviewed journals have compared laparoscopic and open appendectomy, including >20

randomized, controlled trials and 6 meta-analyses.64,77,80–84 The overall quality of these randomized, controlled trials has

been limited by the failure to blind patients and providers as to the treatment modality used. Furthermore, investigators have

failed to perform prestudy sample size analysis for the outcomes studied.64 The largest meta-analysis comparing open to

laparoscopic appendectomy included 47 studies, 39 of which were studies of adult patients. This analysis demonstrated that

the duration of surgery and costs of operation were higher for laparoscopic appendectomy than for open appendectomy.

Wound infections were approximately half as likely after laparoscopic appendectomy as after open appendectomy. However,

the rate of intra-abdominal abscess was three times higher after laparoscopic appendectomy than after open

appendectomy.64

A principal proposed benefit of laparoscopic appendectomy has been decreased postoperative pain. Patient-reported pain on

the first postoperative day is significantly less after laparoscopic appendectomy. However, the difference has been calculated

to be only 8 points on a 100-point visual analogue scale. This difference is below the level of pain that an average patient is

able to perceive.62 Hospital length of stay also is statistically significantly less after laparoscopic appendectomy. However, in

most studies this difference is <1 day.64,77 It appears that a more important determinant of length of stay after

appendectomy is the pathology found at operation—specifically, whether a patient has perforated or nonperforated

appendicitis. In nearly all studies, laparoscopic appendectomy is associated with a shorter period before return to normal

activity, return to work, and return to sports.64,77,80–84 However, treatment and subject bias may have a significant impact

on the data. Although the majority of studies have been performed in adults, similar data have been obtained in children.64

There appears to be little benefit to laparoscopic appendectomy over open appendectomy in thin males between the ages of

15 and 45 years. In these patients, the diagnosis usually is straightforward. Open appendectomy has been associated with

outstanding results for several decades. Laparoscopic appendectomy should be considered an option in these patients, based

on surgeon and patient preference. Laparoscopic appendectomy may be beneficial in obese patients, in whom it may be

difficult to gain adequate access through a small right lower quadrant incision. In a retrospective study of 116 patients with a

mean body mass index of 35, postoperative length of stay was significantly shorter in the group undergoing laparoscopic

appendectomy, and there were fewer open wounds. In all obese patients in whom the procedure was completed

laparoscopically the incisions closed primarily, whereas the wounds closed primarily in only 58% of obese patients who

underwent open appendectomy. There was no difference in rates of wound infection; intra-abdominal abscess rates were not

reported.85

Diagnostic laparoscopy has been advocated as a potential tool to decrease the number of negative appendectomies

performed. However, the morbidity associated with laparoscopy and general anesthesia is acceptable only if pathology

requiring surgical treatment is present and is amenable to treatment using laparoscopic techniques. The question of leaving

a normal appendix in situ is a controversial one. Seventeen to 26% of appendices that appear normal at exploration are

found to have pathologic features on histologic analysis.80 The availability of diagnostic laparoscopy may actually lower the

threshold for exploration and thus adversely impact the negative appendectomy rate.86 Fertile women with presumed

appendicitis constitute the group of patients most likely to benefit from diagnostic laparoscopy. Up to one third of these

patients do not have appendicitis at exploration. In most of the patients without appendicitis, gynecologic pathology is

identified.87 A large meta-analysis demonstrated that in fertile women in whom appendectomy was deemed necessary,

diagnostic laparoscopy reduced the number of unnecessary appendectomies.64 In addition, the number of women without a

final diagnosis was smaller. It appears that leaving a normal-appearing appendix in fertile women with identifiable

gynecologic pathology is safe.87

In summary, it has not been resolved whether laparoscopic appendectomy is more effective in treating acute appendicitis

than the time-proven method of open appendectomy. It does appear that laparoscopic appendectomy is effective in the

management of acute appendicitis. Laparoscopic appendectomy should be considered part of the surgical armamentarium

available to treat acute appendicitis. The decision on how to treat a specific patient with appendicitis should be based on

surgical skill, patient characteristics, clinical scenario, and patient preference. Additional well-controlled, prospective, blinded

studies are needed to determine which subsets of patients may benefit from any given approach to the treatment of

appendicitis.

NATURAL ORIFICE TRANSLUMINAL ENDOSCOPIC SURGERY

Natural orifice transluminal endoscopic surgery (NOTES) is a new surgical procedure using flexible endoscopes in the

abdominal cavity. In this procedure, access is gained by way of organs that are reached through a natural, already-existing

external orifice. The hoped-for advantages associated with this method include the reduction of postoperative wound pain,

shorter convalescence, avoidance of wound infection and abdominal-wall hernias, and the absence of scars. The first case of

transvaginal removal of a normal appendix has recently been reported.88 Much work remains to determine if NOTES provides

any additional advantages over the laparoscopic approach to appendectomy.

ANTIBIOTICS AS DEFINITIVE THERAPY

Traditional management of acute appendicitis has emphasized emergent surgical management. This approach has been

based on the theory that, over time, simple appendicitis will progress to perforation, with resulting increases in morbidity and

mortality. As a result, a relatively high negative appendectomy rate has been accepted to avoid the possibility of progression

to perforation. Recent data suggest that acute appendicitis and acute appendicitis with perforation may be separate disease

entities with distinct pathophysiology. A time series analysis performed on a 25-year data set did not find a significant

negative relationship between the rates of negative appendectomy and perforation.17 A study analyzing time to surgery and

perforation demonstrated that risk of rupture is minimal within 36 hours of symptom onset. Beyond this point, there is about a

5% risk of rupture in each ensuing 12-hour period. However, in many patients the disease will have an indolent course. In one

study 10 of the 18 patients who did not undergo operation for ≥6 days after their symptoms began did not experience

rupture.89

Many acute abdominal conditions such as acute diverticulitis and acute cholecystitis are managed with urgent but not

emergent surgery. Moreover, evidence from submarine personnel who develop appendicitis suggests that nonoperative

management of appendicitis may be a viable treatment option. Sailors who develop appendicitis while stationed on

submarines do not have access to prompt surgical care. They are successfully treated with antibiotics and fluids days to

weeks after the initial attack until the ship can surface and they can be transferred to a hospital for care.90

A randomized study comparing antibiotic treatment with immediate appendectomy has been completed. Two hundred and

fifty-two men 18 to 50 years of age with the presumptive diagnosis of appendicitis were enrolled in the study between March

1996 and June 1999. For patients randomly assigned to antibiotic therapy, if symptoms did not improve within the first 24

hours, an appendectomy was performed. Participants were evaluated after 1 week, 6 weeks, and 1 year. Acute appendicitis

was found in 97% of the 124 patients randomly assigned to surgery. Six patients (5%) had perforated appendices. The

complication rate in the surgery group was 14% (17 of 124). Of the 128 patients enrolled in the antibiotic group, 15 patients

(12%) underwent operation within the first 24 hours due to lack of improvement in symptoms and apparent local peritonitis.

At operation seven patients (5%) had perforation. The rate of recurrence within 1 year was 15% (16 patients) in the group

treated with antibiotics. In five of these patients a perforated appendix was found at operation.52 Although it initially appears

from these data that the use of antibiotics alone may be reasonable therapy for acute appendicitis, there are several issues to

take into account. First, this study included only men between the ages of 18 and 50 and may not have broad applicability to

all patients with appendicitis, especially those populations known to have higher perforation rates. Second, the incidence of

perforation was 9% in the antibiotic group when patients requiring operation in both the acute and delayed settings are

considered. This compares unfavorably with the perforation rate of 5% for those patients operated on immediately. In

addition, the study follow-up was only 1 year, which suggests that patients receiving only antibiotic therapy may still be at

risk for the development of appendicitis. Finally, when patients are treated with antibiotics alone it is possible that diagnoses

of significant pathology such as carcinoid or carcinoma may be delayed.16 Because no laboratory test or clinical investigation

can reliably distinguish patients whose appendicitis is potentially amenable to conservative treatment, surgery still remains

the gold standard of care for patients with acute appendicitis.

INTERVAL APPENDECTOMY

The accepted approach for the treatment of appendicitis associated with a palpable or radiographically documented mass

(abscess or phlegmon) is conservative therapy with interval appendectomy 6 to 10 weeks later. This technique has been

quite successful and produces much lower morbidity and mortality rates than immediate appendectomy. Unfortunately, this

treatment is associated with greater expense and longer hospitalization time (8 to 13 days vs. 3 to 5 days).91

The initial treatment consists of IV antibiotics and bowel rest. Although this therapy is generally effective, there is a 9 to

15% failure rate, with operative intervention required at 3 to 5 days after presentation. Percutaneous or operative drainage

of abscesses is not considered a failure of conservative therapy.

Although the second stage of this treatment plan, interval appendectomy, has usually been carried out, the need for

subsequent operation has been questioned. The major argument against interval appendectomy is that approximately 50%

of patients treated conservatively never develop manifestations of appendicitis, and those who do generally can be treated

nonoperatively. In addition, pathologic examination of the resected appendix shows normal findings in 20 to 50% of cases.

On the other hand, the data clearly support the need for interval appendectomy. In a prospective series, 19 of 48 patients

(40%) who were successfully treated conservatively needed appendectomy at an earlier time (mean of 4.3 weeks) than the

10 weeks planned because of bouts of appendicitis.91 Overall, the rate of late failure as a consequence of acute disease

averages 20%. An additional 14% of patients either continue to have, or redevelop, right lower quadrant pain. Although the

appendix may occasionally be pathologically normal, persistent periappendiceal abscesses and adhesions are found in 80% of

patients. In addition, almost 50% have histologic evidence of inflammation in the organ itself. Several neoplasms also have

been detected in the resected appendices, even in those of children.16

The timing of interval appendectomy is somewhat controversial. Appendectomy may be required as early as 3 weeks after

conservative therapy. Two thirds of the cases of recurrent appendicitis occur within 2 years, and this is the outside limit.

Interval appendectomy is associated with a morbidity rate of ≤3% and a hospitalization time of 1 to 3 days. The laparoscopic

approach has been used and has been successful in 68% of procedures.92 In a more recent study in children, interval

appendectomy was performed successfully using the laparoscopic approach in all 35 patients.93

Prognosis

The mortality from appendicitis in the United States has steadily decreased from a rate of 9.9 per 100,000 in 1939 to 0.2 per

100,000 today. Among the factors responsible are advances in anesthesia, antibiotics, IV fluids, and blood products. Principal

factors influencing mortality are whether rupture occurs before surgical treatment and the age of the patient. The overall

mortality rate in acute appendicitis with rupture is approximately 1%. The mortality rate of appendicitis with rupture in the

elderly is approximately 5%—a fivefold increase from the overall rate. Death is usually attributable to uncontrolled sepsis—

peritonitis, intra-abdominal abscesses, or gram-negative septicemia. Pulmonary embolism continues to account for some

deaths.

Morbidity rates parallel mortality rates and are significantly increased by rupture of the appendix and, to a lesser extent, by

old age. In one report, complications occurred in 3% of patients with nonperforated appendicitis and in 47% of patients with

perforations. Most of the serious early complications are septic and include abscess and wound infection. Wound infection is

common but is nearly always confined to the subcutaneous tissues and responds promptly to wound drainage, which is

accomplished by reopening the skin incision. Wound infection predisposes the patient to wound dehiscence. The type of

incision is relevant; complete dehiscence rarely occurs in a McBurney incision.

The incidence of intra-abdominal abscess secondary to peritoneal contamination from gangrenous or perforated appendicitis

has decreased markedly since the introduction of potent antibiotics. The sites of predilection for abscesses are the

appendiceal fossa, pouch of Douglas, the subhepatic space, and between loops of intestine. In the latter site abscesses are

usually multiple. Transrectal drainage is preferred for an abscess that bulges into the rectum.

Fecal fistula is an annoying, but not particularly dangerous, complication of appendectomy that may be caused by sloughing

of the portion of the cecum inside a constricting purse-string suture; by slipping of the ligature off a tied, but not inverted,

appendiceal stump; or by necrosis from an abscess encroaching on the cecum.

Intestinal obstruction, initially paralytic but sometimes progressing to mechanical obstruction, may occur with slowly resolving

peritonitis with loculated abscesses and exuberant adhesion formation. Late complications are quite uncommon. Adhesive

band intestinal obstruction after appendectomy does occur, but much less frequently than after pelvic surgical therapy. The

incidence of inguinal hernia is three times higher in patients who have had an appendectomy. Incisional hernia is like wound

dehiscence in that infection predisposes to it, it rarely occurs in a McBurney incision, and it is not uncommon in a lower right

paramedian incision.94

CHRONIC APPENDICITIS

Whether chronic appendicitis is a true clinical entity has been questioned for many years. However, clinical data document

the existence of this uncommon disease.95 Histologic criteria have been established. Characteristically, the pain lasts longer

and is less intense than that of acute appendicitis but is in the same location. There is a much lower incidence of vomiting,

but anorexia and occasionally nausea, pain with motion, and malaise are characteristic. Leukocyte counts are predictably

normal and CT scans are generally nondiagnostic.

At operation, surgeons can establish the diagnosis with 94% specificity and 78% sensitivity. There is an excellent correlation

between clinical symptomatology, intraoperative findings, and histologic abnormalities. Laparoscopy can be used effectively in

the management of this clinical entity. Appendectomy is curative. Symptoms resolve postoperatively in 82 to 93% of

patients. Many of those whose symptoms are not cured or recur are ultimately diagnosed with Crohn's disease.95

APPENDICEAL PARASITES

A number of intestinal parasites cause appendicitis. Although Ascaris lumbricoides is the most common, a wide spectrum of

helminths have been implicated, including Enterobius vermicularis, Strongyloides stercoralis, and Echinococcus granulosis.

The live parasites occlude the appendiceal lumen, causing obstruction. The presence of parasites in the appendix at operation

makes ligation and stapling of the appendix technically difficult. Once appendectomy has been performed and the patient has

recovered, therapy with helminthicide is necessary to clear the remainder of the GI tract.

Amebiasis also can cause appendicitis. Invasion of the mucosa by trophozoites of Entamoeba histolytica incites a marked

inflammatory process. Appendiceal involvement is a component of more generalized intestinal amebiasis. Appendectomy

must be followed by appropriate antiamebic therapy (metronidazole).

INCIDENTAL APPENDECTOMY

Decisions regarding the efficacy of incidental appendectomy should be based on the epidemiology of appendicitis. The best

data were published by the Centers for Disease Control and Prevention based on the period from 1979 to 1984.11 During this

period, an average of 250,000 cases of appendicitis occurred annually in the United States. The highest annual incidence of

appendicitis was in patients 9 to 19 years of age (23.3 per 10,000 population). Males were more likely to develop

appendicitis than females. Accordingly, the incidence during teenage years was 27.6 in males and 20.5 in females per 10,000

population per year. Beyond age 19 years, the annual incidence fell. Among those >45 years of age, the annual incidence

was 6 in 10,000 males and 4 in 10,000 females. When the life table technique was used, the data identified a lifetime risk of

appendicitis of 8.6% in men and 6.7% in women. Although men were more likely to develop appendicitis, the preoperative

diagnosis was correct in 91.2% of men and 78.6% of women. Similarly, perforation occurred more commonly in men than in

women (19.2 vs. 17.8%). In contrast to the number of cases of appendicitis, 310,000 incidental appendectomies were

performed between 1979 and 1984, 62% of the total appendectomies in men and 17.7% of those in women. Based on these

data, 36 incidental appendectomies had to be performed to prevent one patient from developing appendicitis.96

The financial aspects of the decision to perform incidental appendectomy were assessed.97 For open appendectomy, there

was a financial disincentive to perform incidental appendectomy. On an annual basis, $20,000,000 had to be spent to save

the $6,000,000 cost of appendicitis. With the laparoscopic approach, it was cost effective to perform incidental

appendectomy only in patients <25 years of age and only if the reimbursement for surgeons was 10% of the usual and

customary charges. At a higher rate of reimbursement, incidental appendectomy was not cost effective in any age group.

Although incidental appendectomy is generally neither clinically nor economically appropriate, there are some special patient

groups in whom it should be performed during laparotomy or laparoscopy for other indications. These include children about

to undergo chemotherapy, the disabled who cannot describe symptoms or react normally to abdominal pain, patients with

Crohn's disease in whom the cecum is free of macroscopic disease, and individuals who are about to travel to remote places

where there is no access to medical or surgical care.98

Appendectomy is routinely carried out during performance of Ladd's procedure for malrotation, because displacement of the

cecum into the left upper quadrant would complicate the diagnosis of subsequent appendicitis.

TUMORS

Appendiceal malignancies are extremely rare. Primary appendiceal cancer is diagnosed in 0.9 to 1.4% of appendectomy

specimens.16 These tumors are only rarely suspected preoperatively. Fewer than 50% of cases are diagnosed at operation.99

Most series report that carcinoid is the most common appendiceal malignancy, representing >50% of the primary lesions of

the appendix.16,98,99 A review from the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER)

program found the age-adjusted incidence of appendiceal malignancies to be 0.12 cases per 1,000,000 people per year.99

Data from the SEER program identified mucinous adenocarcinoma as the most frequent histologic diagnosis (38% of total

reported cases), followed by adenocarcinoma (26%), carcinoid (17%), goblet cell carcinoma (15%), and signet-ring cell

carcinoma (4%).99 Five-year survival for appendiceal malignancies varies by tumor type. Patients with carcinoid tumors have

the best 5-year survival (83%), whereas those with signet-ring cell cancers have the lowest (18%).99,100

Carcinoid

The finding of a firm, yellow, bulbar mass in the appendix should raise the suspicion of an appendiceal carcinoid. The

appendix is the most common site of GI carcinoid, followed by the small bowel and then the rectum. Carcinoid syndrome is

rarely associated with appendiceal carcinoid unless widespread metastases are present, which occur in 2.9% of cases.

Symptoms attributable directly to the carcinoid are rare, although the tumor can occasionally obstruct the appendiceal lumen

much like a fecalith and result in acute appendicitis.16,100,101

The majority of carcinoids are located in the tip of the appendix. Malignant potential is related to size, with tumors <1 cm

rarely resulting in extension outside of the appendix or adjacent to the mass. The mean tumor size for carcinoids is 2.5

cm.100 Carcinoid tumors usually present with localized disease (64%). Treatment for tumors ≤1 cm is appendectomy. For

tumors larger than 1 to 2 cm located at the base or with lymph node metastases, right hemicolectomy is indicated (Fig. 30-

9). Despite these recommendations, SEER data indicate that proper surgery for carcinoids is not performed at least 28% of

the time.100

Fig. 30-9.

Algorithm for the management of patients with appendiceal carcinoid.

Adenocarcinoma

Primary adenocarcinoma of the appendix is a rare neoplasm with three major histologic subtypes: mucinous adenocarcinoma,

colonic adenocarcinoma, and adenocarcinoid.99 The most common mode of presentation for appendiceal carcinoma is that of

acute appendicitis. Patients also may present with ascites or a palpable mass, or the neoplasm may be discovered during an

operative procedure for an unrelated cause. The recommended treatment for all patients with adenocarcinoma of the

appendix is a formal right hemicolectomy. Appendiceal adenocarcinomas have a propensity for early perforation, although

they are not clearly associated with a worsened prognosis.101 Overall 5-year survival is 55% and varies with stage and

grade. Patients with appendiceal adenocarcinoma are at significant risk for both synchronous and metachronous neoplasms,

approximately half of which will originate from the GI tract.99

Mucocele

A mucocele of the appendix is an obstructive dilatation by intraluminal accumulation of mucoid material. Mucoceles may be

caused by one of four processes: retention cysts, mucosal hyperplasia, cystadenomas, and cystadenocarcinomas. The clinical

presentation of a mucocele is nonspecific, and often it is an incidental finding at operation for acute appendicitis. An intact

mucocele presents no future risk for the patient; however, the opposite is true if the mucocele has ruptured and epithelial

cells have escaped into the peritoneal cavity. As a result, when a mucocele is visualized at the time of laparoscopic

examination, conversion to open laparotomy is recommended. Conversion from a laparoscopic approach to a laparotomy

ensures that a benign process will not be converted to a malignant one through mucocele rupture. In addition, laparotomy

allows for thorough abdominal exploration to rule out the presence of mucoid fluid accumulations.99

The presence of a mucocele of the appendix does not mandate performance of a right hemicolectomy. The principles of

surgery include resection of the appendix, wide resection of the mesoappendix to include all the appendiceal lymph nodes,

collection and cytologic examination of all intraperitoneal mucus, and careful inspection of the base of the appendix. Right

hemicolectomy, or preferably cecectomy, is reserved for patients with a positive margin at the base of the appendix or

positive periappendiceal lymph nodes. Recently, a more aggressive approach to ruptured appendiceal neoplasms has been

advocated. This approach includes a thorough but minimally aggressive approach at initial laparotomy, as described earlier,

with subsequent referral to a specialized center for consideration of re-exploration and hyperthermic intraperitoneal

chemotherapy.101

Pseudomyxoma Peritonei

Pseudomyxoma peritonei is a rare condition in which diffuse collections of gelatinous fluid are associated with mucinous

implants on peritoneal surfaces and omentum. Pseudomyxoma is two to three times more common in females than in males.

Recent immunocytologic and molecular studies suggest that the appendix is the site of origin for the overwhelming majority

of cases of pseudomyxoma. Pseudomyxoma is invariably caused by neoplastic mucus-secreting cells within the peritoneum.

These cells may be difficult to classify as malignant because they may be sparse, widely scattered, and have a low-grade

cytologic appearance. Patients with pseudomyxoma usually present with abdominal pain, distention, or a mass. Primary

pseudomyxoma usually does not cause abdominal organ dysfunction. However, ureteral obstruction and obstruction of

venous return can be seen.102 Pseudomyxoma is a disease that progresses slowly and in which recurrences may take years

to develop or become symptomatic.102 In a series from the Mayo Clinic, 76% of patients developed recurrences within the

abdomen.103 Lymph node metastasis and distant metastasis are uncommon.

The use of imaging before surgery is advantageous to plan surgery. CT scanning is the preferred imaging modality. At

surgery a variable volume of mucinous ascites is found together with tumor deposits involving the right hemidiaphragm,

right retrohepatic space, left paracolic gutter, ligament of Treitz, and the ovaries in women. Peritoneal surfaces of the bowel

are usually free of tumor. Thorough surgical debulking is the mainstay of treatment. All gross disease and the omentum

should be removed. If not done previously, appendectomy is routinely performed. Hysterectomy with bilateral salpingo-

oophorectomy is performed in women. Survival is better in patients who undergo R0 or R1 resection than in patients who

undergo R2 resection (visible gross disease remaining).104 Because 5-year survival of mucinous appendiceal neoplasms is

only 30%, adjuvant intraperitoneal hyperthermic chemotherapy is advocated as a standard adjunct to radical cytoreductive

surgery.105 Cytoreductive surgery with intraperitoneal hyperthermic chemotherapy is a long, tedious procedure with

operative times of 300 to 1020 minutes reported. In addition, morbidity (38%) and mortality (6%) are high. Cytoreductive

surgery with intraperitoneal hyperthermic chemotherapy is associated with a 5-year survival of between 53 and 78%.

Survival is associated with initial patient performance status.104–106

Any recurrence should be investigated completely. Recurrences are usually treated by additional surgery. It is important to

note that surgery for recurrent disease is usually difficult and is associated with an increased incidence of unintentional

enterotomies, anastomotic leaks, and fistulas.102,103

Lymphoma

Lymphoma of the appendix is extremely uncommon. The GI tract is the most frequently involved extranodal site for non-

Hodgkin's lymphoma.107 Other types of appendiceal lymphoma, such as Burkitt's, as well as leukemia, have also been

reported.108 Primary lymphoma of the appendix accounts for 1 to 3% of GI lymphomas. Appendiceal lymphoma usually

presents as acute appendicitis and is rarely suspected preoperatively. Findings on CT scan of an appendiceal diameter ≥2.5

cm or surrounding soft tissue thickening should prompt suspicion of an appendiceal lymphoma. The management of

appendiceal lymphoma confined to the appendix is appendectomy. Right hemicolectomy is indicated if tumor extends

beyond the appendix onto the cecum or mesentery. A postoperative staging work-up is indicated before initiating adjuvant

therapy. Adjuvant therapy is not indicated for lymphoma confined to the appendix.108,109

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