Amphotericin B–resistant Cryptococcus laurentii meningitis with pulmonary tuberculosis in a patient with pauci-immune crescentic glomerulonephritis secondary to MPO ANCA vasculitis in Nepal- a case report

Immunosuppressive therapy for ANCA vasculitis significantly increases the risk of opportunistic infections. While cryptococcal meningitis is a known complication, it is typically caused by Cryptococcus neoformans or C. gattii. Infections with non-neoformans species like Cryptococcus laurentii are uncommon and can exhibit resistance to first-line antifungals. Co-infection with tuberculosis further complicates management due to diagnostic challenges and drug-drug interactions. A 17 year old male with pauci-immune crescentic glomerulonephritis secondary to MPO ANCA vasculitis, on maintenance immunosuppression with cyclophosphamide and prednisolone, presented three months into therapy with headache and vomiting. CSF analysis confirmed cryptococcal meningitis with India ink and cryptococcal antigen positivity. Despite four weeks of liposomal amphotericin B and fluconazole, his CSF remained positive. CSF showed Cryptococcus laurentii with confirmed resistance to amphotericin B (MIC ≥ 16 µg/mL). Antifungal therapy was switched to high-dose fluconazole monotherapy. During admission, he also developed sputum and GeneXpert-positive pulmonary tuberculosis. He was started on antitubercular therapy with rifampicin, necessitating close monitoring of the drug-drug interaction. His neurological and respiratory symptoms improved with therapy, though renal impairment persisted. This case demonstrates that Cryptococcus laurentii can cause cryptococcal meningitis in immunosuppressed patients with potential resistance to amphotericin B. Co-infection with tuberculosis can complicate therapy. Early recognition, drug susceptibility testing, judicious modification of immunosuppression, and monitoring of drug–drug interactions are essential for successful outcome.