(554) Cryptococcal Meningitis: A Diagnostic Conundrum in an Encephalopathic Patient With Multiple Myeloma

Introduction: The heterogeneity of potential etiological factors complicates diagnoses in critically ill oncology patients with acute encephalopathy. This report highlights a case wherein the encephalopathy origin deviated from expectations.

Description: A 74-year-old male, diagnosed with cardiac disease and kappa light chain multiple myeloma (MM) on second line treatment (carfilzomib) and weekly dexamethasone presented with acute encephalopathy. Laboratory findings revealed sodium 151 mEq/L, creatinine 3.2 mg/dL, and radiological evidence of pneumonia. Neuroimaging indicated possible communicating hydrocephalus, recent cerebellar infarction, and suspected leptomeningeal disease (LMD). While monitored on telemetry and receiving treatment for pneumonia and ischemic stroke, he developed intermittent episodes of third-degree heart block prompting admission to ICU. Despite the urgent cardiac situation, interventions were deferred as anticoagulation would delay possible Ommaya reservoir placement. Lumbar puncture revealed an opening pressure of 22-31cm, a lymphocytic preponderance with positive PCR panel for Cryptococcus neoformans (CN) (CSF titer 1:2560). Therapy included a single high dose of amphotericin, flucytosine, fluconazole, and serial lumbar punctures, leading to initial improved mental status. However, CSF remained positive for CN one month after and he ultimately died.

Discussion: Cryptococcus, an opportunistic encapsulated yeast, poses significant mortality risk following inhalation. The presented case posed diagnostic challenges due to multiple comorbidities and lack of characteristic diagnostic findings. The finding of high degree heart block was likely related to increased intracranial pressure (ICP) that occurs in meningitis. The changes in ICP, causing CNS pressure waves, consequently caused the dysrhythmia. Cryptococcosis typically afflicts those with T-cell immunodeficiency such as HIV or lymphoma but rarely reported in MM since cell mediated immunity is largely preserved. However, the duration of MM and cumulative dose of treatment along with steroid use likely suppressed cellular immunity and heightened susceptibility to fungal infections in our patient.