EP476 - Neutropenic Proctitis: A Case Report of Neutropenic Enterocolitis with Rectal Involvement In An Adult Patient

Purpose/Background: Neutropenic enterocolitis (NE) is a severe form of inflammatory colitis commonly seen in immunocompromised patients, typically associated with cytotoxic chemotherapy. While primarily affecting the cecum and distal ileum, there is limited literature on NE with rectal involvement, termed "neutropenic proctitis." This case report describes a 38-year-old female with Graves’ disease treated with methimazole, who developed neutropenic proctitis, contributing novel insights to the understanding of this condition.

Methods/Interventions: The patient presented to the emergency department with fever, chills, diarrhea, and rectal pain following a prior visit for mouth sores. Laboratory tests indicated severe neutropenia (ANC 30/mm³), prompting the discontinuation of methimazole and admission to the ICU for supportive care, including vasopressors and broad-spectrum antibiotics. The patient developed a rapidly progressing erythematous rash on her perineum. CT images showed rectal wall thickening with surrounding inflammatory changes. She underwent emergent wound exploration in the operating room for concerns of necrotizing soft tissue infection (NSTI), but the examination was inconsistent with NSTI. Patient’s perineal wounds and clinical condition continued to decline, necessitating the creation of laparoscopic loop sigmoid colostomy. Flexible sigmoidoscopy was performed at that time, revealing extensive rectal necrosis.

Results/Outcomes: Post-surgery, the patient’s condition stabilized, with resolution of fever and improvement in tachycardia. She was downgraded to a lower level of care after her ANC increased to greater than 500/mm³ on day 10. Despite developing a pelvic abscess that grew Pseudomonas, her clinical status continued to improve, leading to discharge on day 37. The patient later underwent an uncomplicated thyroidectomy and showed ongoing improvement in perineal pain and ostomy function. One year after initial event, manometry shows poor sphincter function. Barium enema and flexible sigmoidoscopy show the rectum is patent and healthy, but mildly strictured. She continues with outpatient pelvic floor physical therapy with the goal to reverse her ileostomy when clinically appropriate.

Conclusion/Discussion: This case highlights the critical challenges in diagnosing and managing neutropenic proctitis, particularly in the context of methimazole treatment. The unique presentation emphasizes the need for a multidisciplinary approach and underscores the importance of early intervention. The association of methimazole with neutropenic proctitis represents a novel finding, warranting further investigation to enhance understanding and management of this rare condition in adults.

Rectal Wall Thickening
CT on admission showing rectal wall thickening and surrounding inflammatory changes.

Rectal Necrosis
Intraoperative flexible sigmoidoscopy showing necrosis of the rectal mucosa.