S2409 Histoplasmosis Presenting as New-Onset Ascites in a Crohn’s Disease Patient on Adalimumab

Abstract

Introduction: Histoplasma capsulatum is the most frequently diagnosed endemic mycosis in the United States. The majority of cases are self-limiting but infections in immunocompromised patients may result in severe pulmonary or disseminated disease. We report a rare case of disseminated histoplasmosis presenting as new- onset ascites due to granulomatous hepatitis in a patient with perianal Crohn’s Disease on Adalimumab. Case description/methods: A 39-year-old white female with perianal but no intraluminal Crohn’s Disease currently on adalimumab and azathioprine presented with cyclical fevers and rapid onset ascites. In the preceding weeks she was noted to have uptrending alkaline phosphatase (600s) with isoenzymes consistent with liver etiology, GGT 162, mildly elevated AST (53) with normal ALT and total bilirubin. Further workup included positive anti-smooth muscle (1:160) and F-actin antibodies. Anti-nuclear and anti-mitochondrial antibodies both returned negative. MRCP demonstrated a circumferential 1.9 x 1.3cm peribiliary mass with segmental biliary duct dilation. Paracentesis with peritoneal fluid analysis demonstrated a low serum-ascites albumin gradient, lymphocytic predominance, and negative cytology, acid-fast stain, tuberculosis PCR, and adenosine deaminase. Transjugular liver biopsy revealed multiple non-necrotizing granulomas surrounded by chronic inflammation, consisting predominantly of lymphocytes and eosinophils. Grocott’s methenamine sliver stain was positive for narrow-based budding yeast, with morphology suggestive of Histoplasma species. Additionally, a quantitative serum Histoplasmosis antigen returned positive at 2.53 ng/ml. Following these findings, a course of IV Amphotericin B was started with eventual transition to PO Itraconazole for 1 year. Discussion: Histoplasmosis capsulatum is a dimorphic fungus that is endemic to the United States, specifically the Ohio and Mississippi River valleys. The majority of infections are subclinical, but when diagnosed are primarily in immunocompromised patients. A high degree of clinical suspicion is required to facilitate early treatment and prevent poor outcomes. Pulmonary histoplasmosis is by far the most common clinical presentation. Progressive disseminated disease is rare, but may involve the liver, skin, adrenals, gastrointestinal tract, central nervous system, and bone marrow. With the use of immunomodulating therapies on the rise, it is important to consider opportunistic infections in patients with atypical presentations.Figure 1.: A: H&E staining at 200x magnification of liver biopsy demonstrating non-caseating granulomas. B: Liver biopsy shows narrow-based budding yeast with positive silver stain suggestive of Histoplasma.