Acute Abdominal Pain
Most children with acute abdominal pain have viral gas- troenteritis or other minor illnesses. Children who are sick-appearing and immunocompromised, and have history of abdominal trauma, signs of bowel obstruc- tion, or evidence of peritoneal irritation require prompt intervention and treatment. Initial resuscitation measures include correction of hypoxemia, replacement of intravascular volume loss, and correction of meta- bolic abnormalities. Empiric broad-spectrum antibiotics Diagnostic tests are sometimes indicated in
patients with severe debilitating abdominal pain with impairment of functioning to reassure the patient, parents, or referring physician that an organic problem is not present. An algorithmic approach for evaluation of patients presenting with chronic or RAP is summa- rized in Figure 1–5.Commonly ordered studies are sum- marized in Table 1–12.
Invasive tests
There is no role for routine use of capsule endoscopy for the evaluation of patients with chronic abdominal pain.
Upper endoscopy is indicated in patients with signifi cant dysphagia, when dyspeptic symptoms persist despite the use of acid-reducing medications or become recurrent on cessation of such medications, hematemesis, and evaluation for Crohn’s disease, for confi rmation of H.
pylori-associated disease, and for confi rmation of celiac disease. Patients with RAP may require colonoscopy in the presence of gastrointestinal bleeding, profuse diar-
FIGURE 1–3 ■ Algorithmic approach to the patient with acute abdominal pain with catastrophic presentation, evidence of intestinal obstruc- tion, localized abdominal tenderness, or suspicion of hepatobiliary disorder. CBC = complete blood count; UA = urinalysis; CT = computed tomography; RUQ = right upper quadrant; RLQ = right lower quadrant; ALT = alanine aminotransferase; AST = aspartate aminotransferase; GGT
=␥-glutamyltransferase.
Abdominal pain < 24 hrs Abdominal distension, focal tenderness, and/or peritoneal sign
• Prostrated, very sick appearing
• Severe, continuous pain
• Unstable vital signs
Catastrohic presentation
Yes Yes Yes Yes
No No No
• Abdominal distension
• Bilious/feculent emesis
•Pain-periumbilical, later RLQ
•Anorexia
•Nausea
•Temperature elevation
• RUQ, or epigastric pain
• Jaundice
• Hepatomegaly
• Nausea, vomiting
• Abdominal plain film
• Urgent surgery consult
• Focused abdominal sonography for trauma (FAST)
• Consider abdominal CT
• Consider diagnostic paracentesis
• Emergency laparotomy
• Abdominal plain film
• Surgery consult
• Ultrasound of RLQ if intussusception suspected
• Possible abdominal CT
• Perforated viscus
• Intra-abdominal hemorrhage/ hematoma
• Bowel ischemia:
necrotizing enterocolitis, volvulus, mesenteric infarction
• CBC. UA
• Surgical consult
• Ultrasound of RLQ
• Abdominal CT
• Laparotomy
• Amylase, lipase
• Liver tests: ALT, AST, GGT, Alkaline phosphatase
• Ultrasound abdomen
• Hepatobiliary scintigraphy
Neonate:
• Volvulus
2 mo – 2 years:
• Intussusception
• Hirschsprung disease
• Incarcerated hernia
> 2 years:
• Adhesions
• Acute pancreatitis
• Acute cholecystitis
• Cholangitis
• Choledocholithiasis
Suspicion of intestinal obstruction
Suspicion of appendicitis
Suspicion of hepatobiliary disorder
Diagnostic consideration Diagnostic
consideration
Diagnostic consideration
are often indicated in immunocompromised patients and when there is clinical suspicion of a serious intra- abdominal infection. Gastric decompression with nasogastric suction is necessary when there is bowel obstruction. Analgesics should be used in patients with moderate-to-severe abdominal pain, preferably after a surgeon has been able to evaluate the patient. Manage- ment strategies for patients with acute abdominal pain are summarized in Figures 1–3 and 1–4.
Chronic Abdominal Pain
If an organic etiology of chronic abdominal pain is identifi ed, disease-specifi c therapeutic measures are instituted. Physicians often feel challenged and frus- trated while caring for patients with FAP. If the patient shows poor response to treatment, it is often perceived as a personal failure on the part of the treating physi- cian. This sense of failure and frustration is exacerbated by a diagnosis that seems uncertain and has no obvious structural basis. It is extremely important for the treat- ing physician to understand the following:
■ FGID are a positive diagnosis, based on clinical crite- ria (Table 1–13).
■ These syndromes are chronic, and the goal of treatment is resumption of normal functioning—not complete eradication of abdominal pain. The physician should reduce expectations for cure and focus on function.
■ The patient and his or her family must understand that they bear signifi cant responsibility for disease management. This is facilitated by the physician’s empathy, support, guidance, and a hopeful attitude.
Evaluation of the patient presenting with chronic abdominal pain is done in the context of the biopsycho- social model of care. Psychological factors alone do not help to distinguish between organic and FGID.
Nevertheless, it is important to identify and address the following factors:
■ Establish an appropriate physician–patient relation- ship. An effective physician–patient relationship is the most important part of the disease management. It is important to validate the symptoms by acknowledg- ing the pain and its impact on the quality of life. Pro- viding a physiological explanation helps to clarify that the symptoms are not imagined. It is also helpful to provide clear age-appropriate examples of conditions associated with hyperalgesia such as chronic head- ache without intracranial pathology, or abnormal sensation at the site of a healing scar. Examples of interaction between the brain and the gut should be mentioned. A good example is diarrhea or vomiting occurring during stressful situations such as sports competition or school examinations. Identifi cation of the patient’s (and the family’s) worries, concerns, and expectations helps physicians to understand the symptoms within a biopsychosocial context. Finally, patients and their family members need reassurance that the symptoms are not caused by a serious disease and do not require extremes of investigation and intervention.
■ Set reasonable therapeutic goals. Therapeutic goals should be established early in the course of treat- ment. The goals are regular school attendance, resumption of normal activities, including participa- tion in extracurricular activities, and reduction in the stress of a chronic disease. Obstacles to school attend- ance (adverse school environment, negative peer interactions, unreasonable academic expectations, and fear of a pain episode at school) must be identi- fi ed and addressed. It is important to discuss the pos- sibility of secondary gains perpetuating the pain behavior. For example, pleasurable activities such as watching television should not be allowed if the patient is sick enough to miss school. It is helpful to maintain a diary detailing the circumstances of pain episodes, aggravating factors, and the emotional and
Abdominal pain < 24 hours Poorly localized or diffuse abdominal tenderness No peritoneal signs
• Low-grade fever, diarrhea, sore throat, headache
• Diffuse or periumbilical non-progressive abdominal pain
Suspect viral syndrome or other self-limiting
infections Yes
• Lower lobe pneumonia
• Pericarditis
• Myocardititis
• Testicular torsion
• Henoch-Schönlein purpura
• Pelvic inflammatory disease
• Acute constipation
• Acute exacebation of functional abdominal pain
• Abdominal migraine flare up
• Acute exacerbation of irritable bowel syndrome
Consider functional bowel disorder
CBC, UA Stool studies, if indicated Throat swab, if indicated Reassessment No
No Consider extra- abdominal causes
FIGURE 1–4 ■ Algorithmic approach to the patient with acute abdominal pain without peritoneal sign, localized pain, intestinal obstruction, or catastrophic presentation. CBC = complete blood count; UA = urinalysis.
FIGURE 1–5 ■ Suggested algorithm for the evaluation of chronic abdominal pain. CBC = complete blood count; CMP = comprehensive metabolic panel; CRP = C-reactive protein; EGD = esophagogas- troduodenoscopy; ESR = erythrocyte sedimentation rate; H. pylori=Helicobacter pylori; IBS = irritable bowel syndrome; O&P= ova and parasite; RLQ = right lower quadrant; RUQ = right upper quadrant;
breath test; UBT = urea breath test; UGI-SBFT = upper gastrointestinal small bowel follow-through; US = ultrasound.
Chronic abdominal pain (at least 1 episode per week for at least 2 months)
•EGD if associated with dysphagia, persistent, or recurrent symptoms, for H. pylori confirmation, presence of alarm signals.
• Add colonoscopyif Crohn disease is suspected
• UGI series for significant vomiting
• Abdominal sonography, hepatobiliary scintigraphy for RUQ pain
• CBC with differential
• ESR, CRP
• CMP
• Stool hemoccult
• Stool H. pylori antigen or 13 C-UBT
• No alarm signals, normal examination, and normal labs
• CBC with differential
• ESR, CRP
• CMP
• Stool hemoccult
• Amylase, lipase, serum C4, urine porphobilinogen, abdominal plain film during paroxysms
• UGI-SBFT
• Abdominal US
• No alarm signals, normal examination, and normal labs
• 2 or more episodes in preceding 12 months
• Associated anorexia, vomiting, photophobia; headache, or pallor
Alarm signals: Involuntary weight loss, growth retardation, significant vomiting, significant diarrhea, gastrointestinal blood loss, extraintestinal symptoms, consistent RUQ or RLQ pain, abnormal physical
examination, anemia, elevated ESR/CRP, elevated liver enzymes, hypoalbuminemia With dyspepsia With diarrhea, or diarrhea
+ constipation With constipation With pain alone With cyclical symptoms
• CBC with differential
• ESR, CRP
• CMP
• Stool hemoccult
• Celiac panel
• Lactose breath test
• Stool O&P, giardia antigen, culture, Clostridium difficile toxin
• CBC with differential
• ESR, CRP
• CMP
• Stool hemoccult
• CBC with differential
• ESR, CRP
• CMP
• Stool hemoccult
• Celiac panel
• EGD if celiac disease suspected
• Add colonoscopy if alarm signals present and infectious etiology excluded
Endoscopy considered in presence of alarm signals, or if pain continues to severely affect lifestyle for reassurance Endoscopy indicated in rare
situations in presence of alarm signals, or for celiac
disease work-up
• No alarm signals, normal examination and normal labs
Functional abdominal pain syndrome
• No alarm signals, normal examination, and normal labs
• No alarm signals, normal examination, and normal labs
• Consider gastric emptying scan, antroduodenal motility studies in selected patients
Functional dyspepsia
IBS
IBS • Evidence of
fecal retention
Functional constipation
Functional abdominal pain
• Loss of daily functioning, somatic symptoms
Abdominal migraine
■ Identify and modify triggers of pain. It is important to identify and possibly reverse physiological and psy- chosocial stress factors that trigger, exacerbate, and perpetuate chronic pain. Dyspeptic symptoms may be associated with gastroesophageal refl ux, delayed gas- tric emptying, or altered gastrointestinal motility.
Other concurrent physiological processes that may trigger pain include celiac disease, constipation, lac- tose intolerance, H. pylori gastritis, aerophagia, spicy food, or exposure to various medications. Chronic use of laxatives, narcotic medications, and nonsteroidal anti-inflammatory drugs must be identified and eliminated when present. Psychosocial stress factors often include parental separation, death in the family, a recent change of school or residence, family mem- bers with signifi cant handicap or illness, altered peer interactions, problems at school, or breakup of a romantic relationship. Identifi cation of these stressors helps in reducing environmental reinforcement of pain behavior. Parents, teachers, and other caregivers are advised to support the child rather than focusing exclusively on the pain. A reasonable timeline for completion of schoolwork accrued during school absence should be negotiated with the school offi cials.
If the child feels overwhelmed with the completion of missed assignments, a reduction of the workload may become necessary. The school offi cials must respond to the pain behavior with empathy and work with the child so that the school attendance or class activities are not disrupted. A child missing school often is caught in a vicious cycle of anxiety regarding accumu- lated schoolwork, anticipation of pain, reduced threshold of pain due to anxiety, and increased dis- tress. A rapid return to school is extremely important.
Psychiatric referral must be done if maladaptive family-coping mechanisms are identified or the patient demonstrates symptoms of anxiety disorder, panic disorder, or depression. Disease exacerbations that are clearly attributable to psychological distress are often amenable to psychological interventions. In cases unresponsive to these common-sense approaches, use of “central analgesics” (tricyclic antidepressants (TCAs) or serotonin–norepinephrine reuptake inhib- itors (SNRIs)) may be considered.
■ Dietary modifi cations. The role of dietary modifi ca- tion in patients with chronic abdominal pain and FGIDs is not well validated. If there are obvious trig- gers such as spicy foods, caffeine, carbonated beverages, lactose, fatty foods, and gas-forming foods (legumes and vegetables of the cabbage family), attempts could be made to reduce or eliminate their intake. In patients with functional dyspepsia and postprandial symp- toms, a trial of frequent small meals or eating low-fat meals may be helpful. Increasing fi ber intake may benefi t patients with both diarrhea-predominant and cognitive responses. An understanding of the patient’s
style of coping, severity of symptoms, and degree of disability helps in devising appropriate treatment strategies.
Pharmacotherapy for Functional Gastrointestinal Disorders
Diagnosis drugs
Functional dyspepsia H2 blockers: famotidine, ranitidine PPI: esomeprazole, lansoprazole,
omeprazole, pantoprazole Prokinetics: erythromycin,
metoclopramide
IBS peppermint oil*, dicyclomine, hyoscyamine
FAP(S) TCA: amitriptyline#, desipramine SNRI: duloxetine, venlafaxine Abdominal migraine cyproheptadine, pizotifen,
propranolol, sumatriptan There are no well-validated published controlled trials on effi cacy and their doses of these pharmacological agents in pediatric patients with functional gastrointestinal disorders. FAP(S) = functional abdominal pain (syndrome);
H2 = histamine 2; IBS = irritable bowel syndrome; PPI = proton pump inhibitor;
SNRI = serotonin–norepinephrine reuptake inhibitor; TCA = tricyclic antidepressant.
*Peppermint oil enteric-coated capsule (187 mg) dose: 30–45 kg, one capsule three times daily; ⬎45 kg, two capsules three times daily.
#Suggested dose of amitriptyline: 0.25 mg/kg/day and slowly titrated up to 1 mg/kg/day.
Table 1–13.
Laboratory and Imaging Studies in Patients with Chronic Abdominal Pain
All patients CBC, CMP, ESR, UA, IgA tissue transglutaminase Diarrhea Stool O&P, C. difficile culture,
lactose breath hydrogen test RUQ, or RLQ pain, cyclic
symptoms, abdominal mass
Abdominal ultrasound,
abdominal and pelvic CT with contrast, UGI-SBFT
Dyspepsia, vomiting UGI, gastric emptying
scintigraphy, 13C-UBT or stool forH. pyloriantigen
Hepatobiliary scintigraphy with CCK
Suggested laboratory and imaging studies in patients with chronic abdominal pain based on clinical presentation. CBC = complete blood count; CCK = cholecystokinin; CMP = comprehensive metabolic panel; ESR = erythrocyte sedimentation rate; O&P = ova and parasite; RLQ = right lower quadrant;
RUQ = right upper quadrant; UA = urine analysis; UBT = urea breath test;
UGI-SBFT = upper gastrointestinal small bowel follow-through.
Table 1–12.
patients with visceral pain. These agents probably act by depressing abnormal neuronal discharges and raise the inappropriately lowered pain threshold of sensitized neurons. These agents must be used with caution because the pediatric experience is limited and the vis- ceral pain indication is off-label.
Similarly, no controlled trial has been conducted in the pediatric population to study the effi cacy of anti- cholinergic agents such as dicyclomine (bentyl) and hyoscyamine (Levbid and Levsin). However, these agents are commonly prescribed. The presumed clinical benefi t is from smooth muscle relaxation due to blockage of muscarinic effects of acetylcholine on gastrointestinal tract. Patients must be cautioned about blurred vision, drowsiness, dry mouth, tachycardia, constipation, and urinary retention when these agents are used.
Peppermint oil is an antispasmodic agent that relaxes intestinal smooth muscle by decreasing calcium infl ux into the smooth muscle cells. Enteric-coated pep- permint oil capsules (Colpermin) had a greater effi cacy than placebo in reducing functional pain in a random- ized double-blind controlled trial consisting of pediat- ric patients with IBS. There are no evidence-based data on the effi cacy of antidiarrheal agents such as loper- amide and diphenoxylate, and bile salt binding agent cholestyramine in patients with diarrhea-predominant IBS.
Polyethylene glycol 3350 is useful in treating con- stipation in patients with constipation-predominant IBS. Fiber supplements such as psyllium, methylcellu- lose, polycarbophil, wheat dextrin, and inulin are effective in treating symptoms of both diarrhea and constipation. Prophylactic agents that are used for abdominal migraine are pizotifen, propranolol, cypro- heptadine, and sumatriptan.4,15,16
■ Psychological treatment. Psychological treatments such as hypnotherapy and cognitive–behavioral therapy (CBT) have been shown to be effective in treating somatic symptoms of adult patients with FGIDs.
There are also emerging data from randomized trials about the effectiveness of these interventions among children and adolescents with FAP or IBS. These tech- niques promote the patient’s ability to self-manage symptoms. Goals of CBT are to identify maladaptive thoughts, perceptions, and behaviors, improve coping and functioning, improve communication and prob- lem solving, and develop ways to improve symptom control. These goals are achieved by modifying dys- functional cognition, abnormal behavior, and errone- ous assumptions or beliefs. Stress management and relaxation techniques such as progressive muscle relax- ation and controlled breathing can be used to alter pain perception by counteracting physiological effects of stress and anxiety. “Gut-directed” hypnotherapy constipation-predominant IBS and FAP. The recom-
mended amount of daily fi ber intake (in grams) is estimated in children by adding 5 to the patient’s age.
Patients with excessive fl atulence may benefi t from avoidance of sorbitol containing chewing gum, car- bonated beverages, legumes, and foods of the cabbage family. A sudden increase in daily fi ber intake may lead to increased colonic gas production, abdominal distension, and worsening abdominal pain.
■ Pharmacotherapy. Published controlled trials regard- ing the efficacy of pharmacological agents for management of FGIDs are rare. Evidence of effi cacy to be greater than placebo has been shown for famoti- dine for functional dyspepsia, pizotifen for abdominal migraine, and peppermint for IBS. Sedatives and anx- iolytics are generally not effective, carry the risk of causing sedation and addiction, and have been shown to have no effect on bowel and sensory symptoms in human control subjects. In patients with functional dyspepsia, antisecretory medications such as H2 blockers or proton pump inhibitors and prokinetic agents (metoclopramide, erythromycin, and domperi- done and cisapride where available) are often offered.
The use of these therapeutic modalities has not been validated by controlled trials, and treatment should not be prolonged in the absence of improvement.
Antidepressants such as TCAs (e.g., desipramine, nortriptyline, and amitriptyline) and SNRIs (e.g., dulox- etine and venlafaxine) have effects on central and peripheral nervous systems, and are useful for treating chronic pain syndromes because of their combined noradrenergic and serotonergic effects. The clinical benefi t could also be due to anticholinergic effects, slow- ing of gastrointestinal transit, fundic relaxation, restora- tion of normal sleep pattern, treatment of comorbid depression, and analgesic effects on receptors through- out the pain transmission system. Physicians must emphasize that these medications are “central analge- sics,” have independent effects on pain, and can be used in lower dosages than are used to treat depression. To assure daily use and adherence, patients and families need to be informed that these medications are not addicting and can be stopped when needed without major withdrawal effects.
Amitriptyline has been studied in pediatric patients, but without any placebo-controlled evidence.
A starting dose of 0.25 mg/kg/day, titrated to a maxi- mum of 1 mg/kg/day over 8–10 weeks, is generally rec- ommended for amitriptyline therapy. In older patients, alternate medications include desipramine (25–75 mg/day) or duloxetine (30 mg/day). There are anecdotal reports of other medications, including phenytoin, car- bamezepine, gabapentin, pregabalin, lamotrigine, topi- ramate, zonisamide, and levetiracetam, benefiting