Clinical features, outcomes, and long-term survival times of cats and dogs with central nervous system cryptococcosis in Australia: 50 cases (2000–2020)

Abstract

Abstract OBJECTIVE To describe the clinical findings and outcomes of Australian cats and dogs with CNS cryptococcosis. ANIMALS 19 cats and 31 dogs with CNS cryptococcosis diagnosed between 2000 and 2020. PROCEDURES A case series and cohort study were performed using the same 50 animals. Both studies were multi-institutional and both retrospective and prospective. Disease features were compared between cats and dogs, and associations between putative risk factors and survival time (ST) were assessed. RESULTS Dogs were younger at initial presentation than cats and had lower latex cryptococcal antigen agglutination titers. Extraneurologic signs were common and frequently involved sinonasal and contiguous tissues. Neuroanatomic localization was predominantly forebrain, central vestibular (including cerebellum), multifocal, or diffuse. CSF analysis predominantly showed pleocytosis, with eosinophilic inflammation common in dogs. Seventy-eight percent (39/50) of patients received antifungal treatment. Median STs (from presentation) in treated patients were 1,678 days for cats and 679 days for dogs. Abnormal mentation at presentation (in dogs) and CSF collection (in cats) were associated with shorter STs. In treated dogs, those that received glucocorticoids prior to diagnosis, or single rather than multiple antifungal agents, had shorter STs. CLINICAL RELEVANCE The prognosis for feline and canine CNS cryptococcosis is guarded, yet long STs are possible with appropriate treatment. Presence of subtle upper respiratory tract signs may suggest cryptococcosis in patients with neurologic signs, while the absence of neurologic signs does not preclude CNS involvement.