Presumptive Nocardia spp. infection in a dog treated with cyclosporin and ketoconazole.

CASE HISTORY: A dog that had received 8 months of cyclosporin and ketoconazole therapy for treatment of atopic dermatitis subsequently developed severe neurological disease, that failed to respond to treatment with trimethoprim-sulphadiazine and clindamycin. HISTOPATHOLOGICAL FINDINGS: Histopathological examination of the pulmonary parenchyma and spinal cord revealed loose aggregates of Gram-positive, partially acid-fast, fine, beaded, filamentous bacteria, most consistent with Nocardia spp.

DIAGNOSIS: A presumptive diagnosis was made of disseminated nocardiosis of the spinal cord and lungs.

CLINICAL RELEVANCE: Nocardia spp. is an opportunistic actinomycete that may cause disseminated disease, particularly in immunocompromised animals. Cyclosporin is used in veterinary medicine to control immune-mediated and allergic disorders, with few reported adverse side effects. This case gives further evidence that involvement of the spinal cord in nocardiosis of the central nervous system (CNS) carries a poor prognosis, and opportunistic infection by Nocardia spp. may be a potential complication of immunosuppressive cyclosporin therapy in the dog.