Case Presentation: A 73-year-old male with history of type 2 diabetes and one-month prior admission for acute renal failure in the setting of stage IV chronic kidney disease presented with symptomatic anemia found to have splenomegaly. A renal biopsy revealed features of membranoproliferative glomerulonephritis and necrotizing crescentic lesions with IgM kappa deposition, suspicious for cryoglobulinemic glomerulonephritis. Immunofixation showed predominant C3 deposits. Our differential included pauci-immune glomerulonephritis versus C3 glomerulonephritis related to IgM monoclonal gammopathy. A bone marrow biopsy, serum and urine protein electrophoresis along with serum immunofixation were negative for pathology. Treatment included 60 mg of prednisone daily in addition to mycophenolate. He remained compliant for almost one month prior to his second presentation. On his second admission, he suffered an ST-elevation myocardial infarction and was started on dual antiplatelet therapy (DAPT). Being that his renal biopsy raised concerns for IgM kappa monoclonal cryoglobulinemic glomerulonephritis, hematology suggested a fine needle aspiration of his mediastinal lymph nodes to rule out a lymphoproliferative disorder. This was not feasible on DAPT. Sadly, the patient developed septic shock from Cryptococcus neoformans fungemia along with encephalopathy and acute hypoxemic respiratory failure requiring intubation and mechanical ventilation. He had a high cryptococcal antigen titer 1:1280 suggesting disseminated infection. The patient passed away on comfort measures.
Discussion: Rapidly progressive glomerulonephritis (RPGN) is characterized by a crescent formation in the glomerulus with immune complex deposition. Patients are put into an immunocompromised state to preserve kidney function, allowing for opportunistic infections such as Cryptococcus to invade. Our patient was on prophylaxis with Atovaquone for pneumocystis pneumonia which begs the question: is there also a place for prophylaxis against Cryptococcus with fluconazole for patients on high-dose prolonged steroid use and could that have prevented his demise? Cryptococcus neoformans is an invasive fungal infection usually found in immunocompromised patients including HIV/AIDs, solid organ transplant recipients, and those on prolonged glucocorticoids (1). There is limited research on using fluconazole as prophylaxis for cryptococcus in immunocompromised patients. A double-blind, randomized, placebo-controlled trial looked at HIV-positive Ugandan adults. The subjects were treated with 200mg of fluconazole three times per week versus placebo. The researchers found that out of 1519 individuals, 19 developed Cryptococcal disease and only 1 of them were in the fluconazole test group (2). More research is needed regarding prophylaxis against cryptococcus for both HIV and non-HIV patients at risk.
Conclusions: RPGN is an exceedingly rare syndrome that manifests as loss of kidney function over a short period of time (3). Early detection and diagnosis affect prognosis and preservation of kidney function. Treatment consists of high-dose corticosteroids and cyclophosphamide, which puts patients in an immunocompromised state and at risk for opportunistic infections. We present a patient who was diagnosed with RPGN and developed cryptococcal bacteremia. More research is warranted on whether prophylaxis against invasive fungal species such as Cryptococcus would be useful in immunocompromised patients.