Gastroenterology
David A. Rudnick
Robert J. Rothbaum
Neonates, infants, toddlers, older children, and adolescents often present with symptoms prompting contemplation of gastroenterologic and hepatic disorders. Examples include abdominal pain, vomiting, diarrhea, constipation, gastrointestinal (GI) bleeding, and jaundice. This chapter reviews considerations relevant to medical evaluation and management of such symptoms that the authors have found useful over decades of clinical practice. Comprehensive discussion of clinical presentation, differential diagnosis, evaluation, and management of these symptoms is beyond the space constraints of this chapter. Thus, the considerations here should augment but do not substitute for the clinical judgment of care providers managing individual patients with specific symptoms.
ABDOMINAL PAIN
In infants and toddlers, caregivers may attribute crying to abdominal discomfort. Flexing the legs, turning red, spitting up, and passing flatus might be interpreted as supportive evidence. However, excessive crying in the absence of other symptoms or signs (such as vomiting, abdominal distension, hematemesis or hematochezia, fever, or general ill appearance) does not typically originate from an intra-abdominal cause.
In school-age children, functional abdominal pain typically occurs almost daily for at least 3 months, is periumbilical, and may have accompanying nausea or vomiting. Physical exam is repeatedly normal. Laboratory tests add little to the evaluation. Anxiety is the most frequent concomitant symptom (1).
In older children and adolescents, abdominal pain is often localized to a specific anatomic region, facilitating diagnostic considerations and evaluations. Pain characteristics, frequency, duration, radiation, and accompanying symptoms are readily definable.
Right upper quadrant pain: Biliary colic is episodic, is often nocturnal, lasts for hours, and then remits. Vomiting may occur.
Epigastric pain: Pain from duodenal ulcer disease and pancreatitis occurs in this region, might follow meals, and lasts for hours. Vomiting may occur.
Left upper quadrant pain: Pancreatitis pain may radiate to this location. Splenic disorders are uncommon in the absence of preexisting splenomegaly.
Right lower quadrant pain: This is the focus of pain with appendicitis. Ovarian cysts and torsion produce acute pain. Ileal Crohn disease causes more chronic discomfort.
Left lower quadrant pain: Colonic or ovarian disorders cause pain in this region.
Findings associated with abdominal pain that increase concern for serious disorders:
History
Acute onset, for example, duration <1 week
Colicky pain with intervening symptom-free intervals
Pain localized distant from the periumbilical region
Associated symptoms:
Vomiting, especially bilious emesis
Hematemesis, hematochezia, or melena
Fever.
Physical Exam
Tachycardia with or without hypotension
Abdominal distension with or without tympany
Direct or indirect rebound tenderness
Referred pain
Hepatosplenomegaly
Abdominal mass
VOMITING
Definitions
Vomiting: forceful expulsion of gastric contents from the mouth
Regurgitation: effortless flow of gastric contents from the mouth (also referred to as infant gastroesophageal reflux [GER], spitting, posseting)
Physiologic GER is common in normal infants. It presents between 1 and 2 months of age, increases over the next few months, and resolves spontaneously. The emesis is gastric contents without blood or bile. GER does not cause excessive crying, poor eating, slow weight gain, apnea, or apparent life-threatening events. If such symptoms or signs are being evaluated, alternative explanations should be sought. Physiologic GER requires no intervention (i.e., no dietary change in infant or mother, no suppression of gastric acid, etc.). Multiple studies document the absence of esophagitis or other complications in such infants. Acid suppression may result in increased risk of pneumonia or gastroenteritis (2,3).
Common Upper GI (UGI) Diseases Associated with Vomiting
Pyloric stenosis: Affected infants have repeated emesis of gastric contents and, occasionally, small amounts of hematemesis. Weight loss can occur. The “olive” is often impalpable. Diagnosis is typically made between 3 and 12 weeks of age.
Esophageal disorders: In affected toddlers, vomiting may occur. Eosinophilic esophagitis can present with dysphagia, vomiting, or both. Anatomic narrowing presents with emesis if solid foods cannot traverse the narrowing. Careful history differentiates dysphagia and regurgitation from emesis of gastric contents. Other than enteric infections, acute gastric and duodenal disorders are uncommon in children without anatomic abnormalities, prior surgery, or ongoing medications.
Esophagitis from acid and peptic injury most often manifests as heartburn with or without dysphagia. Infectious esophagitis produces acute dysphagia and odynophagia. Herpetic infection elicits fever. Candida infection often creates odynophagia. Either infection can occur in immunocompetent and immunodeficient patients.
Less Common and Serious Diseases that Present with Vomiting
Small bowel obstruction due to anatomic abnormality or prior intestinal surgery with adhesions presents with repeated bilious emesis, abdominal pain, and, often, distension with tympany. Urgent evaluation should proceed. Intussusception produces reflex vomiting prior to evolution to obstruction.
Posterior fossa tumor: In all children and adolescents, acute onset of daily vomiting with any associated neurologic symptom (headache, irritability, lethargy, ataxia, decreased activity, diplopia) should prompt careful neurologic exam for cerebellar signs of nystagmus, dysmetria, and ataxia. Fundoscopic exam should be attempted and imaging considered. Posterior fossa brain tumors produce vomiting with or without increased intracranial pressure.
Caustic ingestion: Acute vomiting, dysphagia, refusal to swallow, and drooling characterize esophageal injury due to caustic ingestion. Oral burns or erosions are often but not always present. Usually, caregivers recognize or witness the event.
Esophageal foreign body can present similarly to caustic ingestion, but without evident burns or erosions. A disk battery retained in the esophagus is a medical emergency (4).
Important Disorders Presenting with Vomiting by Age
Infant Vomiting
Bilious emesis: intestinal malrotation with or without volvulus
Malrotation with or without volvulus presents acutely in the first few weeks of life. Abdominal distension and tenderness are often present. Intravascular volume depletion occurs from intraluminal fluid accumulation. Proximal small bowel atresias or stenoses produce a similar clinical picture. Obstructive series may show gasless abdomen or dilated small bowel loops. UGI is diagnostic, demonstrating malposition of the proximal small bowel to the right of the midline and no clear attachment of the ligament of Treitz. Urgent surgical consultation is essential.
Meconium ileus
This condition produces distal small bowel obstruction and nearly always indicates underlying cystic fibrosis (CF). Exam demonstrates abdominal distension, sometimes with visible bowel loops. Obstructive series shows multiple dilated small bowel loops with air-fluid levels.
Hirschsprung disease (5)
This is a distal obstructive disorder of the colon. Abdominal distension, delayed passage of meconium, and bilious emesis are hallmarks of the disorder. Obstructive series demonstrates diffuse dilation of small bowel and, possibly, proximal colon. The gold standard for diagnosis is a rectal suction biopsy (RSB) demonstrating absence of submucosal ganglion cells. Barium enema may help delineate the location of the transition zone and length of aganglionic colon but can also appear normal, especially in the infant <3 months of age.
Nonbilious emesis
This occurs with pyloric stenosis. Exam may not show specific findings. Pyloric ultrasound or UGI study shows thickened and elongated pylorus. Therapy includes intravenous rehydration and pyloromyotomy.
Childhood Vomiting
Bilious emesis
Prior abdominal surgery
History of prior abdominal surgery should prompt consideration of intraabdominal adhesions and associated obstruction. Exam shows abdominal
distension and tenderness with tympany. Obstructive series demonstrates multiple air-fluid levels in dilated small bowel. Therapy includes nasogastric decompression, intravenous hydration, and serial clinical and radiologic exams to gauge the necessity of adhesiolysis.
Other acquired small bowel obstructions (e.g., intussusception, Henoch-Schönlein purpura [HSP]).
Nonbilious emesis
Gastroenteritis is the most common cause of acute nonbilious emesis. Many other GI illnesses (e.g., pancreatitis, chole(docho)lithiasis, peptic ulcer disease, and others) have vomiting as a component.
DIARRHEA
Acute diarrhea in an otherwise healthy individual is often secondary to self-limited infection. Persistence can also be secondary to infection or other malabsorptive, inflammatory, or secretory conditions. No specific duration consistently separates acute versus chronic diarrhea. Acute infectious diarrhea rarely persists >2 weeks.
Acute Infectious Diarrhea
The most common viral causes of uncomplicated acute infectious diarrhea in the United States include rotavirus, enteric adenovirus, astrovirus, and norovirus. Symptoms rarely persist >2 weeks in immunocompetent hosts but can last longer in immunocompromised children.
Bacterial causes in the United States include Campylobacter, Clostridium difficile, E. coli species (enterotoxic, mucosa adherent, enterohemorrhagic [e.g., O157:H7]), Salmonella, Shigella, Yersinia enterocolitica, and Aeromonas and Plesiomonas. Presentation with acute bloody diarrhea should prompt consideration of bacterial infectious diarrhea. Symptoms generally resolve within 1 week.
Shiga toxin producing enterohemorrhagic E. coli O157:H7 causes hemolytic uremic syndrome (HUS). Empiric antibiotic therapy increases risk of adverse HUSrelated outcome. Aggressive hydration with isotonic IV fluids begun at the time of clinical presentation (i.e., prior to culture-based diagnosis) reduces such risk. Thus, patients with acute bloody diarrhea should (i) have stool cultured by a reliable laboratory capable of identifying the bacterial pathogens listed above, (ii) generally not receive empiric antibiotics until E. coli O157:H7 has been excluded, and (iii) be aggressively hydrated with isotonic IVF until E. coli O157:H7 is excluded or the patient’s clinical course indicates resolving risk of HUS development or progression (6).
Nonviral, nonbacterial infectious diarrhea in the United States is caused by Giardia lamblia, Cryptosporidium parvum, Cyclospora cayetanensis, and other parasites. Symptoms can persist for weeks, months, or longer. Diagnostic fecal antigen tests for Giardia and Cryptosporidium are widely available.
Diagnostic Considerations in Infants with Prolonged Diarrhea (7)
Persistent infection (see above)
Intractable diarrhea of infancy (IDI) represents recurrent episodes of diarrhea and poor weight gain or weight loss, usually in infants <6 months old. Typically, IDI occurs in undernourished infants who suffer acute enteritis and then fail to follow the typical course of spontaneous recovery. Diagnosis is based on physician awareness, appropriate exclusion of alternative explanations, and clinical response to nutritional therapy.
Immunodeficiency (e.g., human immunodeficiency virus [HIV], severe combined immunodeficiency [SCID], immune dysregulation, polyendocrinopathy, enteropathy, X linked [IPEX] syndrome, chronic granulomatous disease [CGD], others)
Anatomic abnormality (e.g., malrotation)
Pancreatic insufficiency (e.g., cystic fibrosis, Shwachman-Diamond syndrome, others)
Celiac disease
Cholestasis (i.e., steatorrhea; see page 8: Jaundice [Hyperbilirubinemia])
Hirschsprung disease
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