Antigen negative gastrointestinal histoplasmosis in an AIDS patient

Objective: Adverse events of drug therapy Background: Gastrointestinal involvement in patients with disseminated histoplasmosis is considered common since the organism is identified in the GI tract of approximately 70-90% of autopsy cases. This infection is rarely recognized by clinicians due to its non-specific symptoms. Lesions may occur anywhere in the GI tract but most commonly affects the terminal ileum. Patients present with GI bleeding, intestinal obstruction, ulcerations, masses, and peritonitis. Serum and urine serological antigens are useful for diagnosis because they are positive in over 90% of patients with disseminated disease but may be falsely negative in patients with localized GI involvement. Although histopathology and tissue cultures are specific, limitations include insensitivity and need for invasive procedures. Antifungal agents include intravenous amphotericin B for severe or unstable disease and oral itraconazole for stable disease. Case Report: A 51-year-old HIV positive female presented with abdominal pain, nausea and vomiting. A CT scan of the abdomen revealed circumferential narrowing around a segment of the sigmoid colon with the cecum demonstrating irregular thickened walls. A biopsy of an obstructing duodenal mass found on endoscopy revealed granulomatous inflammation and budding yeasts consistent with Histoplasma spp. She was started on intravenous liposomal amphotericin B and after 2 weeks switched to itraconazole oral solution. Urine and serum histoplasma antigens sent out 2 weeks after antifungal treatment were negative. Conclusions: This case report illustrates the importance of recognizing gastrointestinal histoplasmosis in AIDS patients presenting with non-specific GI symptoms.