263. Antibody Spill-Over vs. True Coccidioidal Meningitis in a Patient with HIV/AIDS and Disseminated Coccidioidomycosis

Abstract

Abstract Background The diagnosis of coccidioidal meningitis merits life-long antifungal therapy given high rates of disease recurrence. Accurate diagnosis is important. Antibody spill-over into cerebrospinal fluid (CSF) can happen when serum titers are high. We present a case of antibody spill-over vs. true fluconazole-resistant coccidioidal meningitis. Methods A 49-year-old man presented with 6 months of intermittent fever, myalgias, decreased appetite, vomiting, diarrhea, unsteadiness and 60-pound weight loss. He was recently diagnosed with HIV and a prior lymph node biopsy had grown Coccidioides immitis (C. i) for which he was given fluconazole 100 mg twice daily. Figure 1. Timeline of Coccidioides immitis lab results in relation to treatment regimen. CF: Complement fixation, EIA: Enzyme immunoassay for Coccidioides antigen, CSF: Cerebrospinal fluid, c/mL: copies/mL, R: resistant, S: susceptible. Results Vitals revealed a temperature of 102°F. He was cachectic and a 0.5 cm right supraclavicular lymph node was palpable. No meningeal signs were appreciated. CD4 count was 50/µL (18%), HIV-1 viral load 2,969,945 copies/mL. Computed tomography (CT) of the abdomen/pelvis suggested lung and spleen involvement. Serum C. i enzyme immunoassay (EIA) was 1.38 ng/mL, immunodiffusion (ID) was positive and complement fixation (CF) titer was 1:256. C. i was isolated from expectorated sputum. CSF cell count was normal, but ID was positive and CF titer was 1:2 however, lab reported concern for spill-over due to high serum IgG titers. He left against medical advice with fluconazole 400 mg daily. He was hospitalized a month later for failure to thrive. MRI head revealed enlarged lateral and third ventricles with increased periventricular hyperintensity concerning for coccidioidal meningitis. Repeat serum studies were stable. CSF revealed CF 1:4 and C. i antigen by EIA 1.31ng/mL, distinguishing between spill-over and meningitis. Susceptibility results showed resistance to fluconazole and amphotericin B with minimum inhibitory concentrations (MICs) of 50 and 4 respectively, posaconazole susceptibility (MIC < 1) and itraconazole borderline (MIC 3.7). Despite amphotericin B resistance, it was used for bridge to posaconazole. ART was initiated after concern for immune reconstitution had resolved. Conclusion This case highlights the difficulty in making an accurate diagnosis of coccidioidal meningitis. It also describes a fluconazole-resistant C. i isolate in the setting of prolonged low-dose fluconazole therapy. Disclosures All Authors: No reported disclosures