Granulomatous meningitis caused by Coccidioides immitis in a dog

Granulomatous meningitis attributable to Coccidioides immitis was diagnosed on postmortem examination in a 4-year-old Border Collie. Clinical signs included CNS disease, aspiration pneumonia secondary to a megaesophagus, and otitis externa. Central nervous system signs included central vestibular and cranial nerve dysfunction. Cerebellar and medullary infiltrates seen on histologic examination affected cranial nerves VIII, IX, and X. Despite extensive diagnostics, diagnosis was not made antemortem. Analysis of CSF suggested suppurative meningitis, but bacteriologic culture results were negative. Coccidioides endospores were identified on reexamination of brain tissue. The clinical course of disease and rate of Coccidioides immitis infection is variable. Causative agents of granulomatous or inflammatory CNS disease may include fungal infection more often than is currently suspected.