Haemorrhagic cerebrovascular accident or stroke in a 16‐year‐old Cob mare

Summary This paper describes the clinical and histopathological features of a 16‐year‐old Cob mare who sustained a haemorrhagic cerebrovascular accident or stroke. The mare presented with an acute onset of neurological signs, with a neuroanatomical localisation to the midbrain and thalamus regions. The mare was reported to have suffered from ataxia on all four limbs which started 7 days prior to referral and was also showing several signs of left‐sided cranial nerve deficits. On initial examination, the mare presented with quadrilateral ataxia, left‐sided facial paralysis, weak tongue tone and a left‐sided nose tilt as well as a hemineglect syndrome characterised by an inability to eat food presented on the right side of her mouth. Complete blood count and biochemistry analyses did not reveal any abnormalities, and a standing head CT revealed the presence of a hyperdense lesion localised in the left ventral cortex and thalamus region, which could be consistent with a vascular lesion, cholesterol granuloma or a mass. The mare was monitored, and as her condition slightly improved, was discharged from the hospital. Four weeks later, the clinical signs recurred and as the ataxia presented a danger for the mare and anyone handling her, the decision was made to euthanise the mare. A post‐mortem CT scan of the head revealed an enlargement of the previous lesion, and the histopathological examination confirmed the presence of a haemorrhage within the brain, associated with neoplastic emboli. Haemorrhagic stroke has not previously been well described in horses therefore presents a challenge in diagnosis. Treatment in small animals is mainly conservative.