A rare case of disseminated histoplasmosis in a patient with Crohn’s disease on immunosuppressive treatment

Excerpt

A 45-year-old male presented in December 2017 with fever, bloody diarrhea, weight loss, fatigue, watery peri-anal discharge, and left lower abdominal colicky pain of 4-month duration. He underwent left hemicolectomy followed by a 9-month anti-tubercular drug treatment with isoniazid, rifampicin, ethambutol, and pyrazinamide for subacute intestinal obstruction and descending colon stricture 4 years back. The resected specimen revealed transmural lymphocytic infiltration and non-caseating granuloma without acid-fast bacilli. Though he remained well for the next 3 years, he experienced recurrent symptoms. A colonoscopy at another hospital at this stage revealed multiple rectosigmoid and colonic ulcers leading to partial stricture (which was also substantiated by a colonoscopy at our hospital later, Fig. 1a) and biopsy revealed moderate mononuclear inflammatory infiltrate in the lamina propria and dilated blood vessels (Fig. 1b). Zeil-Neelson stain was negative for the acid-fast bacilli. Oral prednisolone (50 mg/day) and azathioprine (100 mg/day) were started for a possible diagnosis of Crohn’s disease (CD). After a month, the patient presented with proximal myopathy, bleeding per rectum, and peri-anal ulceration (Fig. 1c), fever, and cervical lymphadenopathy (Fig. 1d). A fine needle aspiration and biopsy of the cervical lymph node revealed histoplasmosis (Fig. 2a–c). Peri-anal ulcer biopsy also revealed histoplasmosis (Fig. 2d). Colonoscopy revealed rectosigmoid ulceration with stricture (Fig. 1a) and biopsy also revealed histoplasmosis (Fig. 3a). Serological test for human immunodeficiency virus (HIV) infection was negative. A computerized tomographic scan showed bilateral adrenal enlargement (Fig. 3b), and thickening of the ileocecal junction (Fig. 3c). With a diagnosis of disseminated histoplasmosis in a patient with CD on immunosuppressive treatment, prednisolone and azathioprine were withheld, treatment with liposomal amphotericin B started, and continued for the next 21 days; his fever subsided, lymph node regressed, peri-anal ulcer showed healthy granulation tissue. At this stage, itraconazole was started. However, he left the hospital due to financial constraint.

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