Toxic megacolon: A rare presentation and novel treatment

Abstract

A 14‐year‐old male presented with toxic megacolon (TM). Stool culture and rectal biopsies ruled out Clostridium difficile infection and Hirschsprung disease, respectively. Anorectal manometry ruled out anal achalasia as rectoanal inhibitory reflex elicited a normal resting pressure. Colonic motility study showed distal colonic dysmotility and was consistent with a history of chronic constipation and encopresis. He initially underwent a diverting loop ileostomy, which ultimately improved his clinical status and resolved his TM without total abdominal colectomy. Diverting loop ileostomy and antegrade colonic enemas for TM should be considered as an alternative to the standard total abdominal colectomy and end ileostomy in the pediatric population.

1. INTRODUCTION

Pediatric patients rarely present with toxic megacolon (TM). Previously described underlying etiologies include inflammatory bowel disease (IBD), Clostridium difficile, Hirschsprung disease (HD), anal achalasia, and ischemic colitis. ¹ , ² The classic treatment for TM is total abdominal colectomy with ileostomy. ² , ³

Constipation in pediatric patients is common, with a prevalence between 0.5% and 32.2%. ⁴ Treatment consists of education, a toilet program, and medication. Refractory constipation may require manometry to guide additional therapies, including rectal irrigations, botulinum toxin injection, cecostomy, and/or colostomy in severe cases.

There are few existing reports of chronic constipation and underlying colonic dysmotility causing TM, none requiring ileostomy. ⁵ We report (according to the Case Reporting guidelines, Supporting Information S1: Supplement 1) the case of a pediatric patient presenting with TM as a complication of constipation, treated initially with ileostomy and antegrade enemas.

2. CASE REPORT

A 14‐year‐old, 150 cm (z‐score: −1.18), 33.5 kg (z‐score: −2.07) male (body mass index [BMI]: 14.9 kg/m²; z‐score: −2.24) presented with 4 days of fever, lethargy, distension, and emesis. His history included poor growth, chronic constipation, and incontinence. He took no medication, had no recent antibiotic therapy, and had no family history of gastrointestinal conditions. Before symptom onset, his stools were at his baseline, which included incontinence weekly. The evening before presentation, he had an uncontrolled, loose, non‐bloody bowel movement.

He was afebrile (97.8°F), had normal vitals (respiratory rate 18 breaths per minute, saturating 98% on room air, blood pressure 121/77) except tachycardia to 137. Physical exam was notable for a soft, distended abdomen. Laboratory evaluation revealed neutrophilic leukocytosis (13.9), anemia (hemoglobin: 9.4), metabolic acidosis, and acute kidney injury. An x‐ray, obtained before administration of narcotic or anticholinergic medications, demonstrated megacolon (Figure 1). Subsequent computed tomography (CT) scan revealed severe colitis with thickening from the transverse colon through the rectum and significant dilation (Figure 2). Therefore, he received a diagnosis of TM. ⁶ , ⁷ Blood cultures were sent, broad‐spectrum antibiotics and intravenous fluids were initiated, and he was kept nil per os. Rectal and nasogastric tubes were placed.

Figure 1.

Initial x‐ray demonstrating megacolon.

Figure 2.

Computed tomography scan at presentation with coronal and axial images of transverse colon and rectum with severe colitis (wall thickening, ahaustral distally).

Infectious stool studies (sent after antibiotic initiation) were negative. He had continued pain but improving distension. On hospital day (HosD) 3, his x‐ray demonstrated an improved gas pattern. He required 1 unit of packed red blood cells (for a hemoglobin of 6.9). Total parenteral nutrition was initiated on HosD 4.

Esophagogastroduodenoscopy and colonoscopy with biopsies were deferred due to perforation risk, with plans to scope and complete a rectal biopsy when stable. Despite response to initial treatment and tolerance of clear liquid diet on HosD 6, he developed rising inflammatory markers and fever on HosD 9–12. Repeat CT revealed persistent colitis. Antibiotics were broadened to piperacillin‐tazobactam.

On HosD 17, he underwent sigmoidoscopy with biopsies, full‐thickness rectal biopsy, and diverting ileostomy for failure of medical management. Anorectal examination was normal. On sigmoidoscopy, the colon appeared edematous (Figure 3A). He underwent laparoscopic‐assisted loop ileostomy. The small intestine appeared normal, but the colon appeared edematous and dilated (Figure 3B). A soft, silicon tube (Pezzer) was positioned through the ileostomy into the right colon for antegrade enema administration.

Figure 3.

Sigmoidoscopy gross findings, hospital Day 17 (A); laparoscopic bowel appearance on hospital Day 17 (B).

Pathology revealed the presence of ganglion cells in the sigmoid colon and fragments of ulcer beds, but no evidence of IBD. Rectal pathology was suboptimal for aganglionosis evaluation. The terminal ileum did not demonstrate any histopathologic abnormality. He recovered well and was discharged on postoperative day (POD) 7.

After 9 days, he presented with fever, abdominal pain, emesis, mild tachycardia, and a tender but non‐distended abdomen. Examination under anesthesia was performed with repeat full‐thickness rectal biopsies, anorectal Botulinum toxin injection, and laparoscopic colonic biopsies to rule out skip‐lesion HD. Pathology demonstrated ganglion cells, ruling out HD. He was discharged home on POD 2.

He underwent further workup, including spine magnetic resonance imaging (normal) to rule out tethered cord and magnetic resonance enterography, revealing no obstruction or inflammation. Additionally, he underwent sedated anorectal manometry (ARM) and colon manometry. ARM demonstrated normal resting pressures and rectoanal inhibitory reflex, inconsistent with anal achalasia. Colon manometry revealed low‐amplitude contractions in the right and transverse colon; propagating contractions were absent in the distal descending and sigmoid colon.

He had improved quality of life with his ileostomy as he was gaining weight and was in school for the first time in years. He ultimately underwent elective ileostomy take‐down, laparoscopic‐assisted left colectomy with cecostomy tube placement, and recovered well. He has been successfully managed with daily saline antegrade enemas. He tolerates school and activities with friends without soiling. At last follow‐up (2 years after initial presentation), he was 171 cm (z‐score: −0.18) and 51.7 kg (z‐score: ‐0.81) (BMI: 17.7 kg/m²; z‐score: −1.17).

3. DISCUSSION

We present the rare case of a 14‐year‐old male with TM, novelly managed initially with a diverting ileostomy allowing for colonic preservation and improved nutritional state. Stool cultures, biopsies, and ARM effectively ruled out IBD, C. difficile, and HD. Ultimately, he was found to have segmental colonic dysmotility secondary to longstanding refractory constipation.

Motility of the gut is a complex interaction of the nervous, endocrine, immune systems, and gut flora. ⁸ , ⁹ Colonic dysmotility has rarely been associated with TM. ⁵ Known causes of TM include ischemia, IBD, C. difficile, neuronal dysplasia, HD, and anal achalasia. ⁷ The standard for surgical management of TM previously involved total colectomy. ² Diverting ileostomy with antegrade enemas has been successfully reported in adult and pediatric patients with known C. difficile, but has not yet been reported in patients with idiopathic TM. ³ , ¹⁰

4. CONCLUSION

Diverting loop ileostomy with antegrade colonic lavage in a pediatric patient was an effective, safe way to manage TM from severe constipation without a total abdominal colectomy, which has not been previously reported. Eventual segmental colectomy, with only the severely diseased portion resected, facilitated improved quality of life. This report of a child with severe, refractory constipation, in addition to previous reports in cases of C. difficile, calls into question the need for colectomy as the standard of care, which can greatly impact a child's quality of life.

CONFLICT OF INTEREST STATEMENT

The authors declare no conflicts of interest.

ETHICS STATEMENT

Written informed consent was obtained.

Supporting information

Supplement 1. CARE‐checklist‐English‐2013.

Davis AP, Schuh JM, Bitong J, Wagner AJ. Toxic megacolon: A rare presentation and novel treatment. JPGN Rep. 2026;7:40‐43. 10.1002/jpr3.70098