Approach to the Child with Recurrent Abdominal PainJohn T. BoyleRecurrent abdominal pain (RAP) is not a diagnosis. The definition of RAP derives from the description by Apley of paroxysmal abdominal pain in children that persists for more than 3 months' duration and affects normal activity. RAP has been reported to occur in 10 to 15% of children between the ages of 4 and 16 years. At least as many children experience chronic pain but maintain normal activity and rarely come to the attention of the physician. By far, the most common cause of RAP is functional pain. The modifier “functional†is used in �gastroenterology if no specific structural, infectious, inflammatory, or biochemical cause for the abdominal pain can be determined. Because the exact etiology and pathogenesis of functional pain are unknown, functional abdominal pain is too often perceived as a diagnosis of exclusion. Diagnostic criteria for functional gastrointestinal disorders have been defined recently by an International Working Team Committee. Although these definitions must be considered relatively arbitrary, given the lack of a well-defined biological basis for any of these syndromes, they provide a framework for a working diagnosis of functional pain based on the absence of alarm signals from history, physical examination, and a focused laboratory evaluation. Management of functional pain is facilitated by early diagnosis, parental education and reassurance, and the clear delineation of goals of therapy. Functional abdominal pain takes the physician out of the paradigm of cure and into the practical aspects of how to enable the patient to function and have a good quality of life despite pain. Management is best accomplished with regular return visits to monitor symptoms and changes in the physical examination and life style.PATHOPHYSIOLOGY AND MORBIDITY OF FUNCTIONAL ABDOMINAL PAINThere is general agreement that functional pain is genuine. The prevailing viewpoint is that the pathogenesis of the pain involves visceral hypersensitivity with the altered conscious awareness of gastrointestinal sensory input, with or without disordered gastrointestinal motility. Painful sensations may be provoked by physiological phenomena or concurrent physical and psychological stressful life events. Examples of physiological phenomena that may trigger pain include postprandial gastric or intestinal distension, intestinal contractions or the migrating motor complex, intestinal gas, or gastroesophageal reflux. Intraluminal physical stress factors that may trigger pain include aerophagia, simple constipation, lactose intolerance, minor noxious irritants such as spicy foods, Helicobacter pylori gastritis, celiac disease, or drug therapy. Systemic physical or psychological stress factors may also provoke or reinforce the pain behavior by altering the conscious threshold of GI sensory input in the central nervous system. Acute or chronic physical illness may unmask functional pain. Psychological stress factors may include death or separation of a significant family member, physical illness or chronic handicap in parents or sibling, school problems, altered peer relationships, family financial problems, or a recent geographic move.It is not clear whether the different clinical presentations of functional abdominal pain result from a heterogeneous group of disorders or represent variable expressions of the same disorder, as suggested by the frequent occurrence of upper and lower bowel symptoms in the same patient. There appears to be a genetic vulnerability P.1358

because of the high frequency of functional disorders in family members. The fact that most children “outgrow†pain symptoms also suggests that variation of neuroendocrine �development may also be a factor in the pathophysiology. In some patients, associated symptoms

including headache, dizziness, motion sickness, pallor, temperature intolerance, and nausea suggest a generalized dysfunction of the autonomic nervous system. Sex, intelligence, and personality traits do not distinguish patients with functional pain from those with organic pain. The majority of patients are of average intelligence. The generalization that patients with functional abdominal pain are superintellects, perfectionists, overachievers, bad mixers, or constant worriers is without foundation. However, there are some data that the incidence of functional gastrointestinal disorders may be higher in patients with mental diagnoses such as attention deficit–hyperactivity, anxiety, depression, school phobia, posttraumatic stress, bipolar, autism, and eating disorders.The morbidity associated with functional abdominal pain is rarely physical but results from interference in normal school attendance and performance, peer relationships, participation in organizations, sports, and personal and family activities. Only one of 10 children with functional abdominal pain attends schools regularly, and absenteeism is greater than 1 day in 10 in 28% of patients. A common misconception is that pain is the direct cause of the morbidity. In fact, focus on symptom relief by parents, school, and physicians reinforces the pain behavior with attention at the time of pain, rest periods during pain, tactile stimulation and medication to alleviate pain symptoms, and absence from school on days of pain. This approach fails to reinforce nonpain responses such as normal activity. Although pain does not originate from its consequences, ongoing pain behavior is often accounted for and modified by its consequences.ESTABLISHING AN EARLY WORKING DIAGNOSIS OF FUNCTIONAL ABDOMINAL PAINPrimary care physicians often have difficulty making a positive diagnosis of a functional gastrointestinal disorder. One problem is that there is rarely a clear distinction between acute and chronic abdominal pain. Primary caregivers must often deal with the evolution of pain from the initial acute presentation to a chronic or recurring problem. A stepwise series of diagnostic studies to make a negative diagnosis of organic pain is usually employed (see Fig. 17-16). Empiric therapy with nonsteroidal antiinflammatory drugs, antispasmodic/anticholinergic agents, and gastric acid–reducing agents may be tried before the time criteria for RAP are met. Rather than being reassured by negative diagnosis or equivocal response to empiric therapy, parents tend to become more frustrated and anxious, particularly if they perceive that a serious disorder is being missed, or the only alternative diagnosis is an emotional or behavioral disorder. Parental uncertainty only increases the stressful environment that provokes or reinforces the pain behavior.The diagnostic evaluation of a child with abdominal pain begins with a history to distinguish chronic from acute pain, subcategorize the clinical presentation, and address alarm signals that affect differential diagnosis. The classic criteria for RAP are met if the duration of pain exceeds 3 months and child or parents relate that the pain alters life style (Table 17-27). The 3-month time interval may be too long, as the normal course of acute pain problems is only 2 to 6 weeks. Pain behaviors include grimacing, verbalizing, sighing, visibly guarding muscles, and rubbing of the painful areas. Common life-style alterations include decreased school attendance, participation in age-appropriate activities, or alteration in eating behavior or sleep pattern. Children with abdominal pain may be subclassified by one of three clinical presentations: (1) abdominal pain associated with symptoms of upper abdominal distress, (2) abdominal pain associated with altered P.1359

bowel pattern, and (3) isolated paroxysmal abdominal pain. The frequent occurrence of upper and lower bowel symptoms in the same patient is not uncommon. Alarm signals in the history and physical exam (Table 17-27) that raise suspicion of an underlying structural, infectious, inflammatory, biochemical, or psychogenic disorder include continuous pain, pain localized away from the umbilicus, pain or diarrhea repeatedly awakening the patient from a sound sleep, pain related to menstrual cycle, back pain, multisystem complaints, anorexia, weight loss, frequent vomiting, evidence of GI bleeding (hematemesis, melena, hematochezia, rectal bleeding, occult bleeding), profuse diarrhea, encopresis, extraintestinal symptoms (fever, rash, joint pain, recurrent aphthous ulcers), and a positive family history of inflammatory bowel disease, peptic ulcer, or migraine headache. Physical findings of linear growth deceleration, localized tenderness in the right upper or lower quadrant, localized fullness or mass effect, hepatomegaly, splenomegaly, back or costovertebral angle tenderness, perianal fissure, fistula, or soiling, and occult blood–positive stools.

TABLE 17-27 DIAGNOSTIC CRITERIA AND ALARM SIGNALS IN CHILDREN WITH PAROXYSMAL ABDOMINAL PAIN

Diagnostic criteria for functional periumbilical abdominal pain   Documentation of chronicity greater than 3 months   Compatible age range, age of onset (6 to 14 yrs)   Characteristic features of abdominal pain   Evidence of physical or psychological stressful stimuli   Environmental reinforcement of pain behavior   Normal physical examination (including rectal exam and stool occult blood)   Normal laboratory evaluation (CBC with differential, ESR, Urinalysis, ?Stool O&P, ?UGI&SBFT)Alarm signals that pain may have an organic cause   Pain awakening the child at night   Localized or persistent pain away from the umbilicus   Involuntary weight loss or growth deceleration   Extraintestinal symptoms (fever, rash, joint pain, recurrent aphthous ulcers, dysuria)   Consistent sleepiness following pain attacks   Blood in stools (guaiac-positive)   Anemia   Elevated erythrocyte sedimentation rate   Positive family history of peptic ulcer disease, inflammatory bowel disease

CBC = complete blood count; ESR = erythrocyte sedimentation rate; O&P = ova and parasites; UGI&SBFT = upper gastrointestinal radiograph with small-bowel follow-through.In the absence of historical or physical alarm signals, the diagnosis of functional abdominal pain should be introduced into the differential diagnosis of abdominal pain persisting a month beyond the usual course of an acute disease (eg, gastroenteritis, urinary tract infection). Functional pain should be presented as a positive diagnosis and as the most common cause of all three clinical presentations of chronic abdominal pain in children. Acceptable terminologies are functional dyspepsia for pain with upper abdominal symptoms, irritable bowel syndrome for pain associated with altered bowel pattern, and functional abdominal pain for isolated paroxysmal

pain. Parents should be told that a diagnosis of functional pain can be made when the duration of pain exceeds 3 months. A brief explanation of the concepts of an altered sensitivity to “normal†bowel activities (visceral hypersensitivity) and altered motility, the concept of �stress factors, and natural history is important. They should also be told early on that functional pain is difficult to eradicate, and some continuing pain will often have to be accepted by the patient. Establishing a working diagnosis of functional pain and initiating conservative therapy before time criteria are achieved does not preclude an ongoing focused diagnostic workup when indicated by changes in the patient's history or physical examination.DIFFERENTIAL DIAGNOSIS OF SUBCATEGORIES OF RECURRENT ABDOMINAL PAINABDOMINAL PAIN ASSOCIATED WITH SYMPTOMS OF UPPER ABDOMINAL DISTRESSSymptoms of upper abdominal distress include pain or discomfort localized in the upper abdomen, pain related to eating, nausea, episodic vomiting, bloating, early satiety, and occasional heartburn and oral regurgitation. Table 17-28 lists the differential diagnosis of abdominal pain associated with symptoms of upper abdominal distress. Alarm signals such as anorexia, vomiting, weight loss, and evidence of GI bleeding (hematemesis, melena, occult bleeding) suggest an upper GI inflammatory, infectious, structural, or biochemical disorder. Focused laboratory evaluation should be performed in any patient with historical or physical alarm signals, including complete blood count with differential, erythrocyte sedimentation rate (ESR), hepatic panel, and pancreatic enzyme measurement. In cases in which recurrent vomiting is a significant part of the history, an upper GI series with small bowel follow-through and abdominal ultrasound should be considered to rule out gastric outlet disorder, malrotation, partial small bowel obstruction, small bowel Crohn disease, gallstones, pseudocyst, hydronephrosis secondary to ureteropelvic junction obstruction, and retroperitoneal mass. Continuous pain, especially in the context of multisystem complaints, is an alarm signal for possible psychiatric disease. Eating disorders should also be considered in any young patient with significant weight loss.

TABLE 17-28 CAUSES OF RECURRENT ABDOMINAL PAIN ASSOCIATED WITH SYMPTOMS OF DYSPEPSIA

Associated with upper GI inflammation   Gastroesophageal reflux disease (GERD)   Peptic ulcer   Helicobacter pylori gastritis   NSAID (nonsteroidal antiinflammatory drug) ulcer   Crohn disease   Eosinophilic gastroenteritis   Ménétrier disease   Cytomegalovirus (CMV) gastritis   Parasitic infection (Giardia, Blastocystis hominis)   Varioliform gastritis   Lymphocytic gastritis/celiac disease   Henoch-Schönlein purpuraMotility disorders   Idiopathic gastroparesis

   Biliary dyskinesia   Intestinal pseudoobstructionPartial small-bowel obstructionExtraintestinal disorders   Chronic pancreatitis   Chronic hepatitis   Chronic cholecystitis   Ureteropelvic junction obstruction   Abdominal migraine   Psychiatric disorders

If possible, it is prudent to stop NSAIDs, iron preparations, and antibiotics such as erythromycin or tetracyclines in a patient complaining of upper abdominal discomfort. Gastroesophageal reflux disease should be suspected when heartburn, defined as a retrosternal burning discomfort that radiates toward the head or oral regurgitation of sour or bitter gastric contents, is a prominent part of the history. In the absence of peptic ulcer disease, the relationship between H. pylori infection and abdominal pain remains unclear. It is not unreasonable to avoid antibody testing altogether and consider treatment only in patients with endoscopically proven infection (see Sec. 17.19.2). Cholelithiasis causes biliary pain, which is typically severe, constant pain in the epigastrium or right upper quadrant that persists for hours and occurs episodically. In relapsing pancreatitis, recurrent severe epigastric pain may persist for days and often radiates to the back. Recurrent epigastric or right upper quadrant pain associated with tender hepatomegaly suggests chronic hepatitis.Criteria for a diagnosis of functional dyspepsia include the following:

Persistent or recurrent pain or discomfort localized in the upper abdomen for more than 3 months.

Associated symptoms of nausea, episodic vomiting, early satiety, bloating, and occasional heartburn and oral regurgitation.

No evidence that organic disease is likely to explain the symptoms. There are no evidence-based data to support a specific diagnostic approach in a patient with no historical alarm signals and normal physical examination.

Short-term (8-week) empiric medical therapy with an H2 blocker or proton pump inhibitor is an acceptable diagnostic test of self-limiting upper GI inflammation in patients with symptoms less than 3 months. Upper endoscopy should be considered in untreated patients with symptoms beyond 3 months, patients who fail to respond to short-term antisecretory therapy, and patients in whom symptoms recur after the end of treatment. Upper endoscopy is the gold standard to rule out inflammatory disorders in the upper GI tract and establish a firm diagnosis of functional dyspepsia. Recognizable objective findings by gross endoscopic examination include superficial erosions, ulcer, stricture, antral nodularity associated with H. pylori gastritis, gastric rugal hypertrophy associated with Ménétrier disease and CMV gastritis, and the small heaped-up, volcanic-like mounds, pocked with a central crater, associated with chronic varioliform gastritis. Objective histologic findings may help to diagnose reflux esophagitis, eosinophilic gastroenteritis, CMV gastritis, H. pylori gastritis, Crohn disease, and celiac disease. In the absence of gross ulcer or histologic evidence of H. pylori, superficial antral gastritis or

duodenitis is of questionable clinical significance and should not dissuade a diagnosis of functional dyspepsia. There is no evidence in children that nonspecific superficial antral gastritis or duodenitis progresses to peptic ulcer. Evaluation of gastric emptying by scintigraphy to rule out gastroparesis and gallbladder function by hepatobiliary scan with ejection fraction to rule out chronic cholecystitis and biliary dyskinesia should be considered only after upper endoscopy and with consultation by a pediatric gastroenterologist. Endoscopic retrograde cholangiopancreatography P.1360

is indicated only if there is biochemical or radiologic evidence of recurrent pancreatitis or biliary-type abdominal pain following cholecystectomy.ABDOMINAL PAIN ASSOCIATED WITH SYMPTOMS OF ALTERED BOWEL PATTERNAltered bowel pattern may include a change in frequency and/or consistency of stools (diarrhea or constipation), pain relieved with defecation, straining or urgency, feeling of incomplete evacuation, passage of mucus, or a feeling of bloating or abdominal distention. Table 17-29 lists the differential diagnosis of abdominal pain associated with symptoms of altered bowel pattern. In patients with diarrhea, focused laboratory evaluation should include a complete blood count with differential, erythrocyte sedimentation rate, stool for parasite ova, and stool for Clostridium difficile toxin. Lactose intolerance or malabsorption of other carbohydrates such as sorbitol (see Sec. 17.18.5) should be considered a potential primary etiology of chronic abdominal pain in the presence of diarrhea. A trial of a lactose-free diet or performance of a lactose breath hydrogen test is prudent in children with pain associated with loose bowels, bloating, and increased flatulence. Alarm signals including evidence of GI bleeding, tenesmus, pain or diarrhea repeatedly wakening the patient from a sound sleep, involuntary weight loss, linear growth deceleration, extraintestinal symptoms (fever, rash, joint pain, recurrent aphthous ulcers), positive family history of inflammatory bowel disease, iron deficiency anemia, or an elevated ESR are indications to pursue a diagnosis of inflammatory bowel disease by colonoscopy and UGI with small bowel follow-through. Diarrhea associated with encopresis suggests chronic fecal retention and megacolon. Serologic testing for celiac disease (see Sec. 17.18.2) should be considered in patients with iron deficiency anemia or secondary amenorrhea. Chronic watery diarrhea is also an indication to perform a colonoscopy to rule out microscopic inflammation that may alter colonic motility and absorptive function. The large volume of diarrhea (400 to 1200 g/d) distinguishes patients with microscopic lymphocytic, collagenous, or eosinophilic colitis from those with irritable bowel, where stool weight in excess of 300 g/day is rare.

TABLE 17-29 CAUSES OF RECURRENT ABDOMINAL PAIN ASSOCIATED WITH ALTERED BOWEL PATTERN

Idiopathic inflammatory bowel disorders   Ulcerative colitis   Crohn diseaseInfectious disorders   Parasitic (Giardia, Blastocystis hominis, Dientamoeba fragilis)   Bacterial (Clostridium difficile, Yersinia, Campylobacter, TB)Lactose intoleranceComplication of constipation (megacolon, encopresis, intermittent sigmoid volvulus)Drug-induced diarrhea, constipation

Gynecologic disordersNeoplasia (lymphoma, carcinoma)Psychiatric disorders

The accuracy of colonoscopy in diagnosing inflammatory conditions of the colon is superior to the barium enema because of the direct visualization of the mucosal surface and the ability to obtain biopsy and culture specimens. Intubation of the terminal ileum can also aid in the diagnosis of Crohn disease. Recognizable objective findings by gross examination with a flexible endoscope include edema, erosions, ulceration, pseudomembranes (discrete yellow plaques on the colonic mucosa), and polyps. Subjective gross endoscopic findings including erythema, increased vascularity, and spontaneous friability become meaningful only in the context of histology because they are subject to more interobserver variation in interpretation. Objective histologic findings include (1) cryptitis, crypt abscesses, and crypt distortion with branching and dropout, suggesting ulcerative colitis or Crohn disease, (2) noncaseating granuloma specific for Crohn disease, (3) fibrosis and histiocyte proliferation in the submucosa suggesting Crohn disease, and (4) epithelial and intraepithelial lymphocytes or eosinophils with or without subepithelial collagen thickening in lymphocytic colitis, eosinophilic colitis, and collagenous colitis, respectively. The latter should be considered specific findings only in patients with profuse diarrhea. Mild superficial increases in interstitial lymphocytes or eosinophils in the absence of crypt distortion or significant diarrhea are nonspecific and should not dissuade the physician from making a positive diagnosis of irritable bowel syndrome.Criteria for a positive diagnosis of irritable bowel syndrome include the following:

Recurrent abdominal pain of at least 3 months' duration. Two of the following three features:

o Relieved with defecation.o Associated with change in the frequency of stool.o Associated with the form or passage of stool.

No evidence that organic disease is likely to explain the symptoms.

Abnormal stool frequency may be defined as more than three bowel movements per day or fewer than three bowel movements per week. Abnormal stool form includes loose/watery stool, lumpy/hard stool, or passage of mucus with stool. Commonly patients report alternating between diarrhea and constipation. Abnormal stool passage may include straining, urgency, or feeling of incomplete evacuation. Many patients with irritable bowel also have symptoms of dyspepsia. Irritable bowel is usually associated with the same autonomic-type symptoms and signs of environmental stress and reinforcement of pain behavior described above for isolated paroxysmal pain. As in all presentations of functional bowel, associated symptoms often include headache, pallor, dizziness, and fatigue.ISOLATED PAROXYSMAL RECURRENT ABDOMINAL PAINThe most common pattern of isolated recurrent abdominal pain involves episodes of acute, intense midline abdominal pain lasting a few hours to several days with intervening symptom-free intervals lasting days to months. Continuous pain, especially in the context of multisystem complaints, is an alarm signal for possible psychiatric disease including malingering and conversion reaction. Behaviors associated with the pain often include grimacing, verbalizing, sighing, visibly guarding muscles, and rubbing of the painful areas. Table 17-30 lists the major

differential diagnoses of recurrent paroxysmal periumbilical abdominal pain in children. It is important to try to see the patient during an attack, as it is frequently the only opportunity to assess alarm signals.TABLE 17-30 CAUSES OF ISOLATED RECURRENT ABDOMINAL PAIN

Functional abdominal painAbdominal migraineIntermittent intestinal obstruction   Crohn disease   Malrotation w/wo volvulus   Intussusception with lead point   Postsurgical adhesions   Small-bowel lymphoma   Eosinophilic gastroenteritis   AngioedemaOccult constipationAppendiceal colicDysmenorrhea   Endometriosis   Ectopic pregnancy   Adhesions from pelvic inflammatory diseaseCystic teratoma of ovaryMusculoskeletal disorders   Muscle pain   Linea alba hernia   DiscitisVascular disorders   Mesentertic thrombosis   Polyarteritis nodosaAcute intermittent porphyriaMental disorders

The Carnett test may help to determine whether pain is arising from the abdominal wall or has an intrabdominal origin. The site of maximum tenderness is found through palpation. The patient is then asked to cross his or her arms and assume a partial sitting position (crunch), which results in tension of the abdominal wall. If there is greater tenderness on repeat palpation in this position, abdominal wall disorders such as cutaneous nerve entrapment syndromes, abdominal wall hernia, myofascial pain syndromes, rectus P.1361

sheath hematoma, or costochondritis should be suspected. Discitis, which is really an osteomyelitis of the vertebral end plate, may present as a combination of back and abdominal pain. The condition is usually associated with intermittent fever, elevated peripheral white blood cell count, and elevated erythrocyte sedimentaion rate.Occult constipation should be suspected if a left lower quadrant or suprapubic fullness or mass effect is appreciated on abdominal exam and rectal exam reveals evidence of firm stool in the

rectal vault or soft stool in a dilated rectal vault with evidence of perianal soiling. Often, a history of constipation or encopresis is unknown to the parent. Parasitic infections, particularly Giardia lamblia, Blastocystis hominis, and Dientamoeba fragilis, may present with chronic pain in the absence of altered bowel pattern. Vomiting associated with acute recurrent pain is an indication to rule out causes of intermittent intestinal obstruction including malrotation, internal hernia, intussusception, and Crohn disease. Meckel diverticulum should not be included in the differential diagnosis of chronic abdominal pain unless there are signs of obstruction suggesting intussusception or GI bleeding.Alarm signals including pain repeatedly awakening the patient from a sound sleep, anorexia, involuntary weight loss, linear growth deceleration, evidence of GI bleeding, and extraintestinal symptoms (fever, rash, joint pain) all require evaluation for Crohn or other rare disorders such as polyarteritis nodosa, intestinal ischemia, eosinophilic gastroenteritis, and angioneurotic edema, which are indistinguishable from Crohn disease on clinical grounds. Suspicion of polyarteritis nodosa rests on evidence of extraintestinal disease, particularly renal involvement. Mesenteric vein obstruction should be considered in adolescents using oral contraceptives. Clinically, it can present gradually with progressive abdominal pain over a period of weeks. Pneumatosis is usually a late finding. The clinical presentation of eosinophilic gastroenteritis depends on the depth of the infiltration by the eosinophilic process (Sec. 17.21.2). Submucosal disease can become manifest with abdominal pain and signs of obstruction. Angioneurotic edema can be heralded by recurrent episodes of pain in the absence of cutaneous or oropharyngeal edema. Family history is usually positive for allergy.Recurrent fever associated with generalized abdominal pain and peritoneal signs suggests the possibility of familial Mediterranean fever. Appendiceal colic is a controversial cause of chronic abdominal pain (Sec. 17.21.7). Appendiceal colic should be suspected in patients with recurrent acute episodes of well-localized abdominal pain and tenderness, most commonly in the right lower quadrant, demonstrated on several examinations.Dull, midline, or generalized lower abdominal pain at the onset of a menstrual period suggests dysmenorrhea. The pain may coincide with the start of bleeding or precede the bleeding by several hours. Gynecologic disorders associated with secondary dysmenorrhea include endometriosis, partially obstructed genital duplications, ectopic pregnancy, and adhesions following pelvic inflammatory disease. Cystic teratoma has been described in prepubertal patients presenting with right or left lower quadrant pain. The vast majority of such patients have a palpable abdominal mass. Benign ovarian cysts in adolescent girls do not cause recurrent abdominal pain.Acute intermittent porphyria (AIP) is a rare disorder characterized by the temporal association of paroxysmal abdominal pain and a wide variety of central nervous system symptoms including headache, dizziness, weakness, syncope, confusion, memory loss, hallucinations, seizures, and transient blindness. AIP is often precipitated by low intake of carbohydrate or by specific drugs such as barbiturates or sulfonamides.Criteria for a positive diagnosis of functional abdominal pain include recurrent pain over a 3-month period with no evidence of organic disease to explain the symptoms. Commonly associated symptoms include headache, pallor, dizziness, and fatigue, at least one of which is observed in 50 to 70% of cases. Although many children will claim to have pain at the time of office visits, their behavior, affect, and activity are seldom consistent with the degree of expressed discomfort. Poorly localized pressure tenderness is frequently elicited during abdominal palpation. The correct diagnosis can be established by focused diagnostic evaluation

based on historical and physical alarm signals and clinical judgment. Laboratory evaluation might include CBC with differential and ESR to screen for an occult systemic inflammatory condition. The decision to do stool ova and parasite studies is dependent on incidence of Giardia lamblia, Blastocystis hominis, and Dientamoeba fragilis within the community. The most valuable diagnostic test in a patient with symptoms suggesting obstruction is an upper GI series and small bowel follow-through. Rare conditions such as lymphoma, angioneurotic edema, mesenteric vein thrombosis with ischemia, eosinophilic gastroenteritis, and pseudoobstruction will also be suggested by UGI. Abdominal ultrasound and abdominal CAT scan have low diagnostic yield for picking up appendiceal abnormalities with recurrent right lower abdominal pain. Colonoscopy and ileoscopy should be performed to rule out Crohn disease in such patients if blood work or UGI-SBFT suggests the possibility of inflammatory disease. Elective laparoscopy with planned appendectomy should be considered in patients with chronic right lower quadrant pain and negative infectious, inflammatory, and anatomic evaluation.Abdominal migraine is a variant of functional abdominal pain. Diagnostic criteria include three or more episodes of intense acute midline pain during a 3-month period lasting several hours to days P.1362

with intervening symptom-free intervals lasting weeks to months. Two of the following features are required for diagnosis: (1) headache during episodes, (2) photophobia during episodes, (3) associated classical unilateral migraine headaches, which may or may not be associated with abdominal pain, (4) family history of migraine, and (5) visual, sensory, or motor aura antedating acute pain. Associated episodes of cyclic vomiting (see Sec. 17.7.1) or diarrhea are often temporally associated with the abdominal pain. All other causes of episodic severe abdominal pain, including intermittent bowel obstruction, obstructive uropathy, relapsing pancreatitis, biliary tract disease, angioedema, and porphyria, should be considered as well as intracranial space-occupying lesions. Treatment approaches are similar to those used for cyclical vomiting.TREATMENT AND PROGNOSIS OF FUNCTIONAL PAIN DISORDERSTREATMENTThe primary goal of treatment is resumption of normal lifestyle, not eradication of abdominal pain. A positive clinical diagnosis, reassurance, explanation, environmental modification, dietary modification, and selective pharmacologic and/or behavioral therapy constitute the mainstay of treatment for patients with all three clinical presentations. A careful explanation of the pathophysiology of the symptoms and the fact that functional pain disorders will not affect future health can have positive therapeutic effects. In many patients the symptoms spontaneously resolve or lessen after a positive diagnosis, suggesting that allaying the patient's or parent's unwarranted fears may remove a significant stress factor triggering symptoms.The first goal is to identify, clarify, and possibly reverse physical and psychological stress factors (see above) that may have an important role in onset, severity, exacerbations, or maintenance of pain. Equally important is to reverse environmental reinforcers of the pain behavior. Parents and the school must be engaged to support the child rather than the pain. Regular school attendance is essential regardless of the continued presence of pain. In many cases it is helpful for the physician to communicate directly to school officials to explain the nature of the problem. School officials must be encouraged to be responsive to the pain behavior but not to let it disrupt attendance, class activity, or performance expectations. Within the family, less social attention should be directed toward the symptoms. Consultation with a child psychiatrist or psychologist

may be indicated when there is concern about maladaptive family coping mechanisms or if attempts at environmental modification do not result in a return to a normalized life style.It is important to address symptoms of mental disorders that may contribute to the pathogenesis of pain symptoms. Failure to treat attention deficit/hyperactivity, anxiety, or depression will adversely affect pain management. Anxiety may be primary, part of adjustment to an identifiable stress, or associated with panic disorder. Symptoms of anxiety include irritability, exaggerated startle response, poor concentration, worry, hypervigilance, motor restlessness, nervousness, difficulty sleeping, school phobia, fear of separation, and fatigability. Depressive mood is suggested by insomnia, anorexia, overeating, low energy, poor concentration, tearfulness, low self-esteem, poor concentration, feelings of hopelessness, and recurrent thoughts of death. Often there is a fine line between anxiety and depression. Many patients and parents are unable or unwilling to report feeling states or acknowledge a relationship between psychogenic stresses and pain symptoms. It is best to limit discussion of psychological issues to what the patient and family can accept and let the physician–patient/family relationship evolve by continuing to listen actively, provide empathy, and educate about potential benefit of relaxation techniques and coping strategies. Referral for psychological treatment can be proposed as part of a multicomponent treatment package to help the patient more successfully manage the pain symptoms. It is critical that the psychologist or psychiatrist initially focus on illness behavior and expand psychotherapeutic treatments as indicated only as the patient or parents begin to see the benefits of referral.The role of dietary modifications in the management of functional pain disorders is not established. Postprandial symptoms in functional dyspepsia may be improved by eating low-fat meals or by ingesting more frequent but smaller meals throughout the day. A high-fiber diet is recommended for both diarrhea-predominant and constipation-predominant irritable bowel and isolated functional pain. The goal for fiber intake in grams is calculated as the patient's age + 5. Excessive fiber in the diet may result in increased gas and distension and actually provoke pain. Malabsorption of dietary carbohydrates may act as a provocative stimulus in functional abdominal pain. Most often, the patient does not perceive a temporal association between ingestion of a particular sugar and the abdominal pain. Avoidance of excessive intake of milk products (lactose), carbonated beverages (fructose), dietary starches (corn, potatoes, wheat, oats), or sorbitol-containing products (vehicle for oral medication, sugar substitute in gum and candy, ingredient in toothpaste, and a plasticizer in gelatin capsules) is not unreasonable. Excessive gas in patients with IBS can be managed by advising the patient to eat slowly, to avoid chewing gum, and to avoid excessive intake of carbonated beverages, legumes, foods of the cabbage family, and foods or beverages sweetened with aspartame.There are no evidence-based data on the effects of pharmacologic therapy in pediatric patients with functional dyspepsia. After a firm diagnosis of functional dyspepsia is established by upper endoscopy, it is not unreasonable to continue acid inhibition therapy in patients who initially responded to short-term empiric treatment but had recurrence of pain symptoms with attempts at step-down therapy. Short-term step-up therapy with a proton pump inhibitor may be tried in patients who previously did not respond to an H2 blocker. Prokinetic therapy has been reported to provide superior symptom improvement compared to placebo in adults, especially in patients with dysmotility-like dyspepsia, where the predominant complaint is an unpleasant discomfort in the upper abdomen characterized by upper abdominal fullness, nausea, early satiety, or bloating, however, no effective agent is now available in the United States. At present, metoclopramide is the only option for treating pediatric patients and effectiveness has not been established.

Metoclopramide has a significant side-effect profile, including drowsiness, dystonic reactions, and increased prolactin levels. As stated above, although H. pylori eradication therapy is not established to be effective in adults with functional dyspepsia, the available data clearly do not rule out the possibility. Thus, most pediatric gastroenterologists still recommend treating documented H. pylori in conjunction with endoscopic established functional dyspepsia. Although widely used in clinical practice, antispasmodic/anticholinergic and antinauseant drugs have not been superior to placebo in the few adult studies performed to date.There are also no evidence-based data on the effects of pharmacologic therapy in pediatric patients with irritable bowel syndrome. Synthetic opioids such as loperamide and diphenoxylate are effective in treating IBS-associated diarrhea. Loperamide is preferred over diphenoxylate because it does not traverse the blood-brain barrier. Fiber supplements such as psyllium, methylcellulose, or polycarbophil are effective in treating both constipation and diarrhea, P.1363

but their value in relief of IBS-associated abdominal pain is controversial. Nonstimulating laxatives such as mineral oil, milk of magnesia, and lactulose are effective adjuncts in treating constipation-predominant IBS. Antispasmodic/anticholinergic agents are commonly used in clinical practice to treat visceral abdominal pain, although efficacy is controversial.Although there is a lack of formal randomized placebo-controlled trials, there has been a recent surge in the use of antidepressant and psychotropic agents to treat both diarrhea-predominant IBS and functional dyspepsia in adults. Anecdotally, this class of drugs appears to be effective in adults with or without psychiatric abnormalities, especially low-dose tricyclic antidepressants. These drugs may act as “central analgesics†to raise the perception threshold for abdominal �pain or down-regulate pain receptors in the intestine. There are as yet no data on treatment of pediatric patients.There is a recent surge in the development of novel drugs for irritable bowel syndrome in adults, including 5-hydroxytryptamine (5-HT3 and 5-HT4)-receptor antagonists and κ-opioid agonists aimed at restoring normal visceral sensation. Significant beneficial effect of the 5-HT3 antagonist alosetron has been reported in diarrhea-predominant adult women with IBS; however, ischemic colitis has recently been observed as a complications of this agent, limiting its use.Hospitalization is rarely indicated for patients with functional abdominal pain. Fifty percent of patients experience relief of symptoms during hospitalization. However, no data have been presented that the natural history of the pain is affected. Hospitalization does not enhance the fundamental goals of environmental modification. More commonly it will reinforce pain behavior.PROGNOSIS OF RECURRENT FUNCTIONAL ABDOMINAL PAIN IN CHILDRENThere are no prospective studies of the outcome of any of the various presentations of functional abdominal pain. Once functional abdominal pain is diagnosed, subsequent follow-up rarely identifies an occult organic disorder. Interestingly, pain resolves completely in 30 to 50% of patients by 2 weeks after diagnosis. This high incidence of early resolution suggests that child and parent accept reassurance that the pain is not organic and that environmental modification is effective treatment. Nevertheless, more long-term studies suggest that 30 to 50% of children with functional abdominal pain in childhood experience pain as adults, although in 70% of such individuals the pain does not limit normal activity. Thirty percent of patients with functional abdominal pain develop other chronic complaints as adults, including headaches, backaches, and menstrual irregularities. Based on a small number of patients, Apley and Hale have described

several factors that adversely influence prognosis for a lasting resolution of pain symptoms during childhood, including male sex, age of onset less than 6 years, strong history of a “painful family,†and more than 6 months elapsed time from onset of pain symptoms to �established functional diagnosis.ReferencesApley J: The Child with Abdominal Pains. London, Blackwell Scientific, 1975Boyle JT: Recurrent abdominal pain: an update. Pediatr Rev 18:310–321, 1997Rasquin-Weber A, Hyman PE, Cucchiara S, et al: Childhood functional gastroinfestinal disorders. Gut 45(Suppl II): II60–II68, 1999Walker LS, Guite JW, Duke M, Barnard JA, Greene JW: Recurrent abdominal pain: a potential precursor of irritable bowel syndrome in adolescents and young adults. J Pediatr 132:1010–1015, 1998