Horner's Syndrome in Dogs – A Review

Abstract

Horner's syndrome is characterized by the symptoms of miosis, anisocoria, ptosis, enophthalmos and protrusion of the third eyelid as a result of an interruption in the sympathetic nervous system extending from the hypothalamus of the brain to the eye. It has been identified in almost every mammal, including humans. The sympathetic nervous system consists of 3 main parts and these are the central, preganglionic and postganglionic neurons. In order to find the interruption on this system, diagnosis and differential diagnosis must be made and the underlying ethiology of the disease must be found. For this, an accurate examination and lesion localization is required. Topical application of cocaine to the eyes is considered the gold standard in the pharmacological method of lesion localization. Although there are many underlying etiologies, idiopathic Horner's syndrome in dogs is more common than other etiologies. Apart from the pharmacological methods, radiology, CT and MRI imaging techniques are also common tools used to determine the ethiology.