History
Patients with necrotizing enterocolitis (NEC) may exhibit a wide spectrum of illness, ranging from mild disease with only guaiac-positive stools to severe disease with peritonitis, perforation, shock, coagulopathy, and death. The onset is usually insidious, but illness may progress rapidly. The first sign is abdominal distention with gastric retention, emesis, and discomfort. Illness may progress to hemodynamic compromise. A plain film radiograph of the abdomen can assist in the diagnosis.
Infants with allergic colitis present with blood and mucus in the stool, vomiting, and diarrhea after introduction of milk when they are aged approximately 1 week to 3 months. The symptoms may also be mild and may be indistinguishable from esophageal reflux. The syndrome is also known to occur in exclusively breastfed infants, as a reaction to food allergens present in the mother’s diet and appearing in the breast milk.
The typical presentation of milk-protein sensitivity colitis is the acute onset of blood-streaked mucoid diarrheal stool in a well-appearing infant younger than 6 months. The infants do not appear sick or dehydrated, and weight gain is typically within normal limits.
Patients with pseudomembranous colitis typically present with profuse watery or mucoid diarrhea, tenesmus, fever, abdominal cramps, and tenderness, usually within 1 week of antibiotic therapy. The stools may be frankly bloody or guaiac-positive.
The onset of IBD, with Crohn disease (CD) or ulcerative colitis (UC), is usually insidious, consisting of growth failure, weight loss, diarrhea, and occult rectal bleeding. Growth failure is more common in children with CD (35-88%) than in those with UC (6-12%). Weight loss has been reported in as many as 68% of children who are diagnosed with IBD.
UC tends to run a more severe course in children than in adults. Abdominal pain and diarrhea, with or without occult blood, are the most common symptoms at presentation. The pain is frequently colicky and, in CD, may localize to the right lower quadrant or periumbilical area. Frank rectal bleeding is more common in UC than CD.
Perianal disease, including fissures, skin tags, fistulae, and abscesses, occurs in 15% of children with CD and may precede the intestinal manifestations by several years, leading to a misdiagnosis that may include infectious colitis, iron deficiency anemia, juvenile rheumatoid arthritis, and growth disorders.
Arthralgias and arthritis are among the most common extraintestinal complaints in UC. The presence of ankylosing spondylitis is more consistent with CD than with UC. Pubertal development may be delayed or arrested in active UC. Aphthous stomatitis is often present during the initial attack or relapse of UC. Renal calculi develop in 6% of patients, mainly as uric acid in UC and as oxalate in CD. Ophthalmic complications (eg, uveitis, iritis, and episcleritis) may be a sign of IBD or secondary to corticosteroid therapy in patients treated for IBD.
IBD is characterized as mild, moderate, or severe, depending on stool frequency, amount of abdominal tenderness, fever, and hemoglobin and albumin concentrations.
Salmonellae may cause food-borne outbreaks, often in summer and fall. The child experiences abdominal cramps and nausea after an incubation period of 8-48 hours following ingestion of a contaminated source (food or water). The stools are watery and may contain blood. Fever is noted in most children.
Shigellae may cause asymptomatic infection, mild gastroenteritis, or bacillary dysentery. Bacillary dysentery begins suddenly with fever and abdominal pain, and diarrhea begins shortly thereafter. Stools are frequent (10-12/day, on average) and contain mucus and blood; tenesmus is common. Fever is noted, often in the range of 102-104°F (39-40°C). Shigella infection occasionally produces central nervous system (CNS) irritation and presents as seizure, even before other manifestations of the illness arise.
Campylobacter enteritis is characterized by the abrupt onset of fever and abdominal pain, shortly followed by diarrhea. Temperature often remains normal in children younger than 3 months but may be as high as 40°C in older children. Vomiting is uncommon. Two thirds of the children may have severe abdominal pain. The stools are watery and occur 2-20 times daily; they contain blood in 50-95% of cases. Infection is acquired through ingestion of raw meat, poultry, fish, and water.
Yersinia enterocolitica infection presents with the abrupt onset of watery diarrhea that may contain blood. Most of the patients experience severe abdominal pain, which may be mistaken for appendicitis. Older children have a febrile response, with temperatures ranging from 99° to 104°F. Joint pain secondary to arthritis and rashes occur in 5-10% of patients with yersiniosis.
Amebiasis is manifested clinically as dysenteric colitis, commonly presenting with bloody diarrhea, abdominal pain, and fever. B coli causes symptoms similar to those of amebiasis.
Henoch-Schönlein purpura (HSP) is preceded by upper respiratory infection in one third to three fourths of patients. The patient presents with colicky abdominal pain, migratory arthritis affecting the larger joints, and a symmetric purpuric rash that is most noticeable over the extensor surfaces of the arms, legs, and buttocks.
Physical Examination
NEC may present with abdominal distention, tenderness, and guarding. Hypotension, tachycardia, tachypnea, hypoxia, shock, disseminated intravascular coagulation (DIC), and cardiopulmonary arrest may be noted. The stool may have frank blood or may be heme-guaiac positive.
Allergic colitis presents with blood and mucus in the stool. Children are usually well-appearing; however, in rare cases, in patients with allergic enterocolitis, the colitis is severe, and the children may become anemic and present with failure to thrive.
Pseudomembranous colitis presents with diarrhea with frank blood or a guaiac-positive stool. An abdominal examination may elicit tenderness. Signs of perforation, peritonitis, and toxic megacolon may be present and may require an emergent colectomy.
IBD may present with pallor, tachycardia, abdominal tenderness, and blood in the stool. An elevated temperature, weight loss, and dehydration may be noted. The presence of abdominal distention with decreased or absent bowel sounds is indicative of actual or impending obstruction or perforation. Rarely, CD causes intestinal obstruction. Toxic megacolon is a life-threatening complication of UC and CD. Toxic megacolon almost always involves the transverse colon and may present with ileus, peritonitis secondary to perforation, and sepsis. It is a medical and surgical emergency.
Amebiasis may present with temperature elevation, hematochezia, abdominal tenderness, or complications such as liver abscess, colonic perforation, and peritonitis.
HSP presents with a purpuric symmetric rash, commonly over the legs, buttocks, and arms. Asymptomatic microhematuria occurs in 80% of affected patients. The child may have hypertension, proteinuria, and hematochezia. Joint swelling may be present.
Complications
The most serious acute complication of UC is toxic megacolon with the risk of perforation. It is reported to occur in up to 5% of all patients with UC but is a relatively uncommon entity in pediatric patients. Toxic megacolon is more common in UC than in CD. In a single-center case-controlled study of toxic megacolon in children, only 2/10 patients had a CD phenotype; the remainder had UC. [11]
The risk of colon cancer increases after 8-10 years of having UC. The complications of CD tend to increase with time and include bowel strictures, fistulas, abscess, and intestinal obstruction. After surgery, patients may develop short bowel syndrome and malabsorption. The complications of colitis caused by IBD are addressed in greater detail in the articles on Crohn disease and ulcerative colitis.
Hemolytic uremic syndrome (HUS) is the best-known and most important complication of colitis caused by enterohemorrhagic E coli (EHEC).
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Necrotizing enterocolitis totalis.
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Inflammatory bowel disease. Severe colitis noted during colonoscopy. The mucosa is grossly denuded, with active bleeding noted. This patient had her colon resected very shortly after this view was obtained.
