Disseminated Gastrointestinal Histoplasmosis Resulting in Benign Ileal Stricture in a Patient with Hyperimmunoglobulin M Syndrome

Abstract

Gastrointestinal histoplasmosis (GIH) is common in patients with disseminated disease affecting both immunocompetent and immunocompromised patients. However, it is often unrecognized due to a lack of specific signs and symptoms. It has only rarely been reported to cause small bowel obstruction (SBO), and the majority of reported cases were in patients with AIDS. We describe a case of GIH presenting with ileal stricture in a patient with hyperimmunoglobulin M (IgM) syndrome. A 37-year-old male with a past medical history of congenital hyper-IgM syndrome treated with regular immune globulin infusions and recently diagnosed disseminated histoplasmosis confirmed by laparoscopic mesenteric lymph node biopsy. The patient was status post a two week course of amphotericin B switched to maintenance itraconazole following undetectable urine histoplasma antigen level and significant clinical improvement. Shortly after initial completion of therapy, the patient had suffered a complicated course with three admissions over the course of two weeks with abdominal pain and CT confirmed SBO with each episode treated conservatively. Upon the patient's fourth presentation, gastroenterology was consulted for further investigation. CT enterography demonstrated 6 cm nodular thickening across the terminal ileum and a tight ileal stenosis. Additionally, a urine histoplasma antigen was elevated. Colonoscopy with ileoscopy confirmed stenosis and dilation was achieved with CRE balloon dilator. Biopsy of the stricture showed active ileitis without granulomas. Given his previous history of disseminated histoplasmosis associated with imaging and laboratory abnormalities, GIH was highly suspected. The patient elected to continue itraconazole rather than amphotericin B due to its side effect profile. Urine histoplasma antigen level was undetectable at 1-month follow-up and no further SBO episodes occurred. GIH is usually characterized by segmental inflammation and ulceration of the GI tract. However, these findings may be incorrectly attributed to malignancy and inflammatory bowel disease leading to the inappropriate use of immunosuppressive medications. This case demonstrates the diagnostic value of CT enterography and urine histoplasma antigen in GIH when pathology results are non-diagnostic as well as the effectiveness of endoscopic therapy. It also highlights the unusual occurrence of a short segment of stricture as the result of an otherwise disseminated process.Figure 1Figure 2