[Encephalopathy and Alzheimer type II astrocytes in a post laparotomy recumbent horse]

A 13-year-old Standardbred gelding was referred for evaluation of continuous abdominal pain. Rectal examination revealed a dislocated large colon (Dislocatio coli ad dextram). The horse showed muscle fasciculations and appeared lethargic. It was sent to surgery because of persistent colic. In transit the gelding showed an unstable walk and immediately prior to surgery a wide-based stance in the hindlimbs. Laparotomy revealed a retroflexion of the large colon and a secundary mesenterial volvulus. After surgery the horse remained recumbent. Due to the comatose state and poor prognosis the gelding was euthanized after 15 hours of recumbency. Necropsy indicated hyperaemic meninges, edema of gliacells and submeningeal tissue with vacuolization and loss of several cerebellar Purkinjecells as well as multiple conglomerates of Alzheimer type II astrocyte groups within the grey matter. Further findings included marked hepatolipidosis, multiple gastric ulcers, small intestinal hyperaemia with mild mononuclear inflammation, tapeworm-infestation of the caecum and moderate chronic enteritis with eosinophilic component in the large intestine. To the best of our knowledge, this was the first case of a horse with colic and concurrent encephalopathy without primary liver disease described in a German-speaking country.