a comprehensive review on appendicitis

8/3/2019 A comprehensive review on Appendicitis

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ACUTE APPENDICITISBy: Prabhjot P. Singh, M.D.Xavier University School Of Medicine



ANATOMY • The appendix becomes visible in the 8th week

of embryologic development as a

protuberance off the terminal portion of the

cecum

• The growth rate of the cecum exceeds thatof the appendix, so that the appendix is

displaced medially toward the ileocecal valve.



ANATOMY ( c o n t d . ) • The base of the appendix to the cecum remains constant,

whereas the tip can be found in a retrocecal, pelvic,subceacal, preileal, or right pericolic position.

• length varies from >1 cm to <30 cm; mostly 6 to 9 cm



• The three taeniae coli

converge at the junction

of the cecum with the

appendix and can be a

useful landmark to

identify the appendix.

• These anatomic considerations have significant clinical

importance in the context of acute appendicitis.

ANATOMY ( c o n t d . )



ANATOMY ( c o n t d . ) • 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.



• Recent studies have shown Appendix is an immunologic

organ that actively participates in the secretion of

immunoglobulins, particularly immunoglobulin A.

• Earlier it was believed that there is a potential

correlation between appendectomy and the development

of inflammatory bowel disease; Crohn's disease &ulcerative colitis.

• But recent data suggests that appendectomy may

protect against the subsequent development of

inflammatory bowel disease; however, the mechanism isunclear.

Vestigial organ ??



INCIDENCE (contd.)

of appendiceal rupture.

The percentage of misdiagnosed cases is significantly higher among

women than among men (22.2 vs. 9.3%).

Despite the increased

use of ultrasonography,

CT, and laparoscopy, the

rate of misdiagnosis of

appendicitis has

remained constant(15.3%), also the rate



• Obstruction of the lumen is the dominant etiologic factor in

acute appendicitis. The frequency of obstruction rises with the

severity of the inflammatory process.

• Most common cause of obstruction : Fecaliths.

• Less common-

• Tumors (1̊ or metastatic cancer & carcinoid syndrome),• vegetable and fruit seeds,

• inspissated barium from previous x-ray studies,

• intestinal parasites,

•

foreign bodies,• Crohn's disease.

PATHOGENESIS



• Lymphoid hyperplasia of submucosal follicles:

-viral illnesses including upper respiratory infection,-mononucleosis,

- gastroenteritis

Lymphoid hyperplasia is more common in children andyoung adults, accounting for the increased incidence of

appendicitis in these age groups. This is known as

Catarrheal Appendicitis.

PATHOGENESIS ( c o n t d . )



• Fecaliths are found in

• 40% of cases of simple acute appendicitis,

• 65% of cases of gangrenous appendicitis without

rupture and

• nearly 90% of cases

with rupture.

PATHOGENESIS (c o n t d .)



• The proximal obstruction of the lumen produces a closed-loop .

• Continuing normal secretion by the mucosa rapidly

produces . Luminal capacity of the normal

appendix is only 0.1 mL. Secretion of 0.5 mL of fluid distal

to an obstruction raises the intraluminal pressure to 60

cm H2O.

• also is stimulated by distention.

PATHOGENESIS (c o n t d .) obstruction

distention

Peristalsis



• increases from continued mucosal secretion and rapid multiplication of the resident bacteria of the

appendix.

• Distention stimulates the nerve endings of visceral

afferent stretch fibers

in the midabdomen or lower

epigastrium.

• Distention of this magnitude usually causes


vague, dull, diffuse pain

reflex nausea and vomiting.

Distention



• As pressure in the organ increases, capillaries and venules are occluded

• The inflammatory process soon involves the serosa of

the appendix and parietal peritoneum in the region


pain to the right lower quadrant.

engorgement and vascular congestion.



usually through one of the infarcted areas

beyond the point of obstruction


Compromise of

Vascular Supply



Focal (Acute) - increase luminal presure & lymphatic obs’n

leads to edematous appendix.

Suppurative

Gangrenous

- venous thrombosis, arterial compromise

leads to Gangrene formation.

Ruptured

(Perforation)

- further increase in pressure, & venous obstruction leads to

bacterial invasion

-usually through one of the infarcted areas on the

antimesenteric border, beyond the point of

obstruction.



SYMPTOMS ( c o n t d . ) Retrocolic appendix

: flank or back painRetroileal appendix

: testicular pain

Pelvic appendix

: suprapubic pain

If the appendix lies entirely within the pelvis, there is usually

complete absence of the abdominal rigidity.

A Digital Rectal Examination elicits tenderness

in the rectovesical pouch.



SYMPTOMS ( c o n t d . ) 3. Nausea

4. Vomitting

5. Diarrhea

6. hx of obstipation

In >95% of patients with acute appendicitis,

anorexia is the first symptom,

followed by abdominal pain

followed by vomiting



S IGNS Coughing causes point tenderness in McBurney's point

(also known as Dunphy's sign).

Direct rebound Tenderness:

there is severe pain on suddenly releasing a deep pressure in

lower abdomen

Referred or indirect rebound tenderness:

This referred tenderness is felt maximally in the right lower

quadrant, which indicates localized peritoneal irritation.



Rovsing's sign:

continuous deep palpation starting from the left iliac fossa

upwards may cause pain in the right iliac fossa.

Psoas sign:

Patient lies on the left side as the examiner slowly extends the

patient's right thigh, thus stretching the iliopsoas muscle.

Obturator sign:

hypogastric pain on stretching of obturator internus muscle by

flexing and passive internal rotation of the hip while patient issupine.

S IGNS ( c o n t d . )



Abdominal guarding:

tensing of the abdominal wall muscles to guard inflamed organswithin the abdomen.

Cutaneous hyperesthesia :

abnormal increase in sensitivity to stimuli of sense, in the area

supplied by the spinal nerves on the right at T10, T11, and T12.

S IGNS ( c o n t d . )



LABS

- Plain radiographs can be beneficial to R/O other pathology.

- In patients with acute appendicitis, abnormal bowel gas pattern is

seen, 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 painfrom a right lower lobe pneumonic process.



• With acute, uncomplicated appendicitis

– Mild leukocytosis, 10,000 to 18,000 cells/mm3, – Often accompanied by moderate polymorphonuclear

predominance.

• perforated appendix with or without an abscess

– white blood cell count >18,000 cells/mm3 – U/A is useful to r/o Urinary Tract Infection.

– several white or red blood cells can be present from

ureteral or bladder irritation, bacteriuria is not seen in

acute appendicitis.



LABS ( c o n t d . ) Barium enema examination and radioactively labeled leukocytescans:

-If the appendix fills on barium enema, appendicitis is excluded.

- If the appendix does not fill, no determination can be made.



LABS ( c o n t d . ) - an accurate way to establish the diagnosis.

- inexpensive, can be performed rapidly.

- does not require a contrast medium.

- can be used even in pregnant patients.

The appendix is identified as:

- blind-ending, nonperistaltic bowel loop originating from the cecum.

-easily compressible, blind-ending tubular structure.

-measures ≤5 mm in diameter.

- The presence of an appendicolith establishes the diagnosis.

Ultrasonography :



results are positive, if a

noncompressible appendix

≥6 mm in the

anteroposterior direction.Thickening of the

appendiceal wall and the

presence of

periappendiceal fluid is

highly suggestive of appendicitis.

LABS ( c o n t d . ) Ultrasonography :



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 reportedsensitivity of 55 to 96% and a specificity of 85 to 98%.

Sonography is similarly effective in children and pregnant women,

although its application is somewhat limited in late pregnancy.




Location of the

appendixduring

pregnancy.



Acute appendicitis.scan through an inflamed appendix(between electronic calipers) show that itis enlarged. Note the central echogenicmucosal lining

Acute appendicitis with target sign.

scan through an inflamed appendixshows an intact echogenic submucosallayer and a fluid-filled lumen (F),resulting in a “target” appearance



Sonography can identify abscesses in cases of perforation !!!

Acute appendicitis with an appendicolith.Scan through an inflamed appendix showan echogenic appendicolith with acousticshadowing.

Perforated appendicitis with intraperitonealabscess.Scan through the pelvis demonstrates anoval, complex mass immediately above thebladder (B ), which proved to be anabscess. Note the echogenic appendicolith

within the mass



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,

- in obese patients 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,

- is markedly enlarged and mistaken for small bowel,-or is perforated and therefore compressible.

Ultrasonography :

LABS ( c o n t d . )



CT SCAN

Normal Appendix Abnormal appendix with appendicolith



Abnormally dilated appendix ndemonstrates a thickened enhancingwall and no filling w contrast

Perforated appendicitis.The appendix (solid arrows) is abnormallydilated with a thickened enhancing wall.Small pockets of extraluminal air (dashedarrows) indicate perforation

ALVARADO SCALE



This scoring system was designed to

improve the diagnosis of appendicitis by

giving relative weight to specific clinical

manifestation.

Scores of 9 or 10 are almost certain

to have appendicitis.

(no further work up required)

scores of 7 or 8 have a high

likelihood of appendicitis.

scores of 5 or 6 are compatible with,

but not diagnostic of, appendicitis(CT scanning is appropriate)

scores of 0 to 4 make it extremely

unlikely (but not impossible) that they

have appendicitis.



Delay 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 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)

CT scan may be beneficial in guiding therapy.



Rate of appendiceal rupture by age group.



Appendiceal rupture occurs most frequently distal to thepoint 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)

a wbc count of >18,000 cells/mm3

Mostly 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.



Phlegmons and small abscesses can be treated conservatively with

IV antibiotics.

Well-localized abscesses managed by percutaneous drainage.

Complex abscesses considered for surgical drainage.

If operative drainage is required, should be performed using an

extraperitoneal approach (with appendectomy reserved for cases inwhich 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.



Preoperative Preparations

Adequate hydration should be ensured

electrolyte abnormalities should be corrected

pre-existing cardiac, pulmonary, and renal conditions

should be addressed.

Preoperative antibiotics are used to lowering the

infectious complications in appendicitis.



Post-operative : 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 – 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-generationcephalosporin, monobactam, or aminoglycoside plus

anaerobic coverage with clindamycin or metronidazole is

indicated.

The recommendations are similar for children.



• Schwartz’s Principles of Surgery

• F Charles Brunicardi, Dana, & co-authors, 9th

edition, USA

• Textbook of Surgery

• S Das, 5th edition, India

• Wikipedia

• http://en.wikipedia.org/wiki/Appendicitis

http://en.wikipedia.org/wiki/Appendicitis

http://en.wikipedia.org/wiki/Appendicitis

a comprehensive review on appendicitis

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