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

Abstract

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.