Post-anaesthetic myelopathy in a 3-year-old Friesian gelding

A 3-year-old Friesian stallion was referred to the Department of Equine Sciences at Utrecht University with signs of colic. Laparotomy was performed and the stallion was castrated bilaterally because of an incarcerated inguinal hernia. Intestinal resection was not performed. Eight days postoperatively, the horse showed signs of severe colic and was admitted for re-laparotomy. After resection of 1.5 m of strangulated jejunum and severe intraoperative hypotension, bradycardia, and electrolyte disorders, the horse showed problems during recovery with signs of hindquarter paralysis. There was no pain perception in the hind limbs and there were no patellar or anal reflexes. The muscles of the hindquarters and the long extensor muscles of the back were soft and not painful on palpation. No improvement was seen 60 minutes after intravenous injection of corticosteroids. Because of the tentative diagnosis of post-anaesthetic myelopathy and its poor prognosis, and the fact that the horse was restless and did not accept being lifted with a sling system, the horse was euthanized with the owner's consent. Post-anaesthetic myelopathy is a rare neuropathological condition in the horse. Because of its low incidence, knowledge about its aetiology and contributing factors is rather limited. This case report presents the clinical observations and the anaesthetic protocol and compares this case with previously reported cases in the literature.