%0 Journal Article
%T A review of Horner¡¯s syndrome in small animals
%A Bruce H. Grahn
%A Danielle M. Zwueste
%J Archive of "The Canadian Veterinary Journal".
%D 2019
%X Horner¡¯s syndrome arises from dysfunction of the oculosympathetic pathway and is characterized by miosis, enophthalmos, protrusion of the third eyelid, and ptosis. It has been recognized in a wide variety of breeds and ages in small animal patients. The oculosympathetic pathway is a 3-neuron pathway. The central/first order neuron arises from the hypothalamus and extends down the spinal cord. The preganglionic/second order neuron arises from the first 3 thoracic spinal cord segments and travels through the thorax and cervical region until it synapses at the cranial cervical ganglion. The postganglionic/third order neuron travels from this ganglion to the orbit. Topical application of cocaine is the gold standard for differentiating Horner¡¯s syndrome from other causes of miosis. Topical 1% phenylephrine allows for identification of a post-ganglion Horner¡¯s syndrome. Numerous etiologies have been reported for Horner¡¯s syndrome, but idiopathic disease is most common. Ancillary diagnostics include otoscopic examination, thoracic radiographs, or advanced imaging. Treatment and prognosis are determined by the etiology
%U https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6294019/