Bilateral laryngeal paralysis (aplegia) occurring late during the recovery of a horse after orthopaedic surgery

Summary A 9‐year‐old male castrated Standardbred was presented for evaluation of a comminuted right front first phalanx fracture. On initial clinical examination, mild haemoconcentration and increased vital parameters were noted. After overnight hospitalisation, the horse underwent general anaesthesia for surgical fracture repair. The horse was positioned in lateral recumbency with a neutral position of the neck. Initial recovery from anaesthesia was uneventful, with the horse standing within 45 min. Thirty minutes after extubation, with the horse back in its stall, complete upper airway obstruction (UAO) was noticed. The horse was immediately re‐anaesthetised, and an emergency tracheostomy was performed. Additionally, furosemide and mannitol were administered. During the subsequent intensive care period, bilateral laryngeal aplegia was diagnosed with upper airway endoscopy. Days later, the horse also displayed neurological signs (hindlimb ataxia, decreased tongue tone) reminiscent of equine protozoal myeloencephalitis (EPM), which was therefore considered a top differential diagnosis and the cause of the laryngeal aplegia. After initiation of empirical treatment, as well as anti‐inflammatory treatment for potential neuroborreliosis, slow but progressive improvement of some neurological signs occurred, resulting in full resolution of tongue weakness but not of ataxia. Due to persistent laryngeal dysfunction, a permanent tracheal stoma was ultimately required.