A case of Cushing's reflex secondary to a focal brainstem lesion refractory to mannitol therapy in an adult canine

Abstract Intracranial hypertension (IH) is a life‐threatening consequence of intracranial lesions. General anaesthesia can impair cerebrovascular autoregulation and increase the risk of brainstem herniation, which is associated with the Cushing's reflex (increased systolic blood pressure, bradycardia and apneustic breathing or apnoea). Mannitol or hypertonic saline is an effective first‐line treatment for managing IH. An adult male‐neutered Whippet presenting with evidence of intracranial pathology underwent general anaesthesia for MRI investigations and subsequently displayed signs of IH that was refractory to mannitol therapy but responded to a change in positioning. This case is the first known to the author that documents a Cushing's reflex secondary to a focal brainstem lesion and highlights lessons learned in managing suspected IH that do not respond to mannitol.