EquineReview

In contrast with cats, dogs and humans, facial nerve paralysis is poorly documented in equids. In this retrospective case series, Boorman and colleagues (J Vet Intern Med. 2020; 34:1308–1320. https://doi.org/10.1111/jvim.15767) describe the clinical features of 64 horses presenting with facial nerve paralysis, excluding postoperative cases. The most common aetiology was trauma, with true idiopathic cases being unusual. The majority (92%) of cases presented with unilateral disease. Central nervous system disease was the second most common cause, emphasising the need for thorough clinical and neurological examination in such cases. Over 50% of horses were unable to blink and required specific ocular therapy, and 25% of horses were euthanased (only one of these being a direct result of the facial nerve paralysis). Of the surviving animals, 72% showed complete resolution of paralysis and 14% showed partial improvement. A weaknesses of this study was the lack of advanced imaging (computed tomography) in the majority of cases, resulting in facial nerve paralysis, making it hard to draw valid conclusions with regards to prognostic indicators.