Crohn's Disease Mimicking Enterocolitis in a Patient With an Endorectal Pull‐Through for Hirschsprung's Disease

Hirschsprung's disease or congenital aganglionosis of the colon is the most common cause of lower intestinal obstruction in the neonate. In most cases of Hirschsprung's disease, the zone of aganglionosis extends to the rectosigmoid junction (1). One of the complications after endorectal pull-through for Hirschsprung's disease is enterocolitis. Postoperative enterocolitis, which can mimic idiopathic inflammatory bowel disease, is a serious complication clinically defined as explosive, watery, bloody diarrhea with abdominal distension, often accompanied by fever and vomiting. A milder form involves just diarrhea (2). The postoperative enterocolitis associated with Hirschsprung's disease can occur in the immediate postoperative period or later (3). We describe the first case of a child who underwent a definitive primary endorectal pull-through procedure in the newborn period for Hirschsprung's disease and later showed signs and symptoms of postoperative enterocolitis and in whom ileocolonic Crohn's disease was diagnosed. The patient was an 11-year-old boy with a diagnosis of Hirschsprung's disease in the newborn period after showing symptoms including vomiting and delayed passage of meconium. He underwent a one-stage endorectal pull-through definitive procedure at 1 month of age. Biopsy specimens obtained 4 to 5 cm from the peritoneal reflexion at the time of surgery showed no ganglion cells. Analysis of specimens obtained at the level of the midsigmoid revealed ganglion cells; this section was brought down for the pull-through. He progressed well after surgery and was fully toilet trained by age 2. At age 6 he reported episodic abdominal pain and diarrhea without visible blood. He localized the pain to the epigastric area and reported worsening pain with meals. At age 7 he was seen by a pediatric gastroenterologist for episodic diarrhea and abdominal pain and giardiasis was diagnosed. During the next few years he continued to have intermittent diarrhea and abdominal pain. Annual follow-up visits to the pediatric surgeon revealed no significant findings on examination. At age 10, the patient was noted to have hypochromic, microcytic anemia on a routine complete blood count. The anemia was not responsive to a therapeutic course of oral iron. Repeated examinations of stools for occult blood were negative. The presumptive diagnosis of α-thalassemia trait was made by a hematologist. One month before hospital admission, the patient reported frequent, loose bowel movements. There was no hematochezia. Stools examined for culture and ova and parasites were negative. A stain of the stool for white blood cells was positive. The patient had not gained weight in 1 year and had lost 3 lb in 1 month. His height had declined from the 50th to the 5th percentile during the past 4 years. Family history revealed a maternal grandfather with Crohn's disease. Physical examination was significant for weight in the 10th percentile and height in the 5th percentile for age. Abdominal examination was significant for distension. Rectal examination revealed no perianal disease and guaiac-positive stool. Laboratory values were white blood cells, 5600/mm3; hemoglobin, 9 g/dl; hematocrit, 28%; mean corpuscular volume, 59.6 μm3; platelets, 630,000/mm3; erythrocyte sedimentation rate, 38 mm/hr; albumin, 3.4 g/dl; and serum iron, 12 μg/dl. Stool culture for Clostridium difficile toxin was negative. Metronidazole was initiated at a dose of 20 mg/kg per day for presumed enterocolitis. A colonoscopy was performed which showed a normal neorectum and descending and transverse colon. The ascending colon and cecum appeared nodular with edematous, friable mucosa and spontaneous hemorrhage. Analysis of colonic specimens from the transverse, descending, and sigmoid colon and neorectum revealed no pathologic changes. Analysis of the cecal and ascending colonic specimens revealed acute and chronic inflammation with cryptitis and crypt abscesses with pieces of necrotic granulation tissue consistent with the base of an ulcer. An upper gastrointestinal series and small bowel series showed narrowing and streaky mucosal changes of the distal terminal ileum and cecum consistent with Crohn's disease. At this writing, the patient is well, receiving sulfasalazine and metronidazole. He gained 8 pounds in 2 months. Second laboratory determinations showed erythrocyte sedimentation rate of 19 mm/hr, hematocrit of 33%, and albumin of 3.6 g/dl. The most common clinical manifestation of Hirschsprung's disease is colonic obstruction which is most commonly signaled (94% of cases) by an infant's failure to pass meconium during the first 24 hours of life (1). Our patient's disease manifested in this fashion. Crohn's disease developed insidiously 6 years after Hirschsprung's disease was diagnosed; first with vague abdominal pain, diarrhea, and anemia and then with weight loss, guaiac-positive stools, and significant growth failure. Growth failure has also been reported in patients with long-standing and recurrent enterocolitis (4). Crohn's disease can be a difficult diagnosis in general and especially when it occurs insidiously. In addition, it can be difficult to differentiate postoperative enterocolitis from infectious gastroenteritis or idiopathic inflammatory bowel disease. Because the patient had Hirschsprung's disease, the primary diagnosis considered was postoperative enterocolitis, especially after the stools were noted to be guaiac positive and to contain white blood cells. The patient's condition improved with administration of metronidazole, which can treat both enterocolitis and Crohn's disease. An evaluation for suspected postoperative enterocolitis should include stool cultures, complete blood count, serum chemistry, abdominal radiograph, and sigmoidoscopy (4). A sigmoidoscopy was scheduled and performed, but when there were no abnormal endoscopic findings up to the sigmoid colon, a full colonoscopy was performed. The diagnosis of Crohn's disease would have been delayed if only a limited sigmoidoscopy had been performed. Our patient had initial symptoms somewhat atypical of postoperative enterocolitis 6 years after undergoing definitive one-stage surgery. Enterocolitis has been reported up to 14 years after surgery (5). In a study of 175 children with Hirschsprung's disease, 57 had enterocolitis that developed from 1 to 176 months after endorectal pull-through (mean, 29 months; median, 18 months) (5). There is wide variation in the reported incidence of enterocolitis after endorectal pull-through procedure. In one report of 34 patients who underwent definitive one-stage endorectal pull-through procedures, none had postoperative development of clinical enterocolitis (6). In another study, postoperative enterocolitis developed in 21.4% of 168 patients treated for Hirschsprung's disease (4). Most of these patients underwent a two-stage endorectal pull-through procedure. The cause of enterocolitis after endorectal pull-through is unclear. It has been shown that children with enterocolitis have an abnormal mucosal immune cell population and impaired transfer of immunoglobulins across the mucosa (7, 8). There are qualitative and quantitative alterations in the mucus defensive barrier in both the aganglionic and ganglionic segments implicating an increased susceptibility to infection (9). An association between Hirschsprung's disease and Crohn's disease has not been previously described. Immunologic features common to both diseases include increased expression of major histocompatibility complex (MHC) II and intercellular adhesion molecule (ICAM) I antigens (10-13). Although cytogenetic analysis performed in families with either disorder have revealed a linkage to certain targeted chromosomes, there is no one candidate gene that is common to both disorders (14-18). In summary, this is the first report of a child with Hirschsprung's disease and later development of Crohn's disease. Considering the relatively common occurrence of enterocolitis complicating endorectal pull-through for Hirschsprung's disease, full colonoscopy is not recommended as part of the routine evaluation. A complete evaluation including sigmoidoscopy should be considered in a patient with an atypical occurrence of postoperative enterocolitis after endorectal pull-through for Hirschsprung's disease. This would include significant growth failure and late onset for presumed enterocolitis. Special attention should be given the sigmoidoscopic findings in these patients. If the findings are not typical for enterocolitis, full colonoscopy should be considered.