Suspected acquired narcolepsy causing sudden collapse in 8 dogs

Abstract

BACKGROUND: Acquired narcolepsy has rarely been reported in veterinary medicine. OBJECTIVE: To describe the presentation, clinicopathological features, diagnostic imaging findings, and management of dogs with suspected-acquired narcolepsy. ANIMALS: Eight dogs with clinical features consistent with acquired narcolepsy. METHODS: A call for suspected cases of acquired narcolepsy was made online, followed by a retrospective review of detailed medical records of potential cases. Dogs were included if episodes consistent with cataplexy were present during examination by a board-certified veterinary neurologist and diagnostic work-up included magnetic resonance imaging of the brain and analysis of cerebrospinal fluid. RESULTS: Seven French Bulldogs and 1 Chihuahua (age range, 9-66 months) were included. Meningoencephalitis of unknown origin was diagnosed in 2 dogs, extracranial foci of inflammation were identified in 2 dogs (aspiration pneumonia, esophagitis, otitis media), and no abnormalities were found on diagnostic investigations in 4 dogs. Prednisolone was used in the management of all dogs, 6 dogs received imipramine, and 2 received cytosine arabinoside. An initial remission of signs was observed in all dogs, but a subsequent relapse of clinical signs was recorded for 4 dogs, of which 3 responded to adjustment or resumption of treatment. CONCLUSIONS AND CLINICAL IMPORTANCE: The presence of cataplexy episodes should prompt a thorough diagnostic work-up to exclude the presence of intracranial (and extracranial) pathology. The potential for both remission and relapse of signs in suspected acquired cases is important for clinicians and owners to be aware of.