![]() Its axon continues through the ramus communicans and travels though the thorax within the sympathetic trunk (2a). The preganglionic/second order neuron begins within the gray matter of the first 3 thoracic spinal cord segments (T1, T2, T3). The central/first order neuron begins within the hypothalamus and travels through the lateral tectotegmental spinal tract ( 1). Schematic representation of the oculosympathetic pathway superimposed over a sagittal cervical and thoracic CT image. It is on this basis that we provide this review. It is therefore important to be able to recognize the signs, understand the underlying neuroanatomy, possible differential diagnoses, available diagnostic tools, treatment options, and expected prognosis. A disparate age range can also be found in the literature, with patients presenting anywhere from 5 wk to 17 y of age in dogs, and up to 14 y of age in cats ( 5, 6). One study failed to identify breed predispositions ( 3) while another suggested that golden retrievers, Labrador retrievers, collies, Shetland sheepdogs, weimaraners, and Doberman pinschers are over-represented ( 4). Horner’s syndrome is well-known in small animal medicine and has the potential to affect any breed of cat or dog, although there is a lack of consensus on the population most likely to be affected. Ptosis was also present, but the eyelids are being retracted in the photo to emphasize the anisocoria. Note the miosis, enophthalmos, and prolapsed third eyelid. Le traitement et le pronostic sont déterminés par l’étiologie.Ĭlinical manifestation of unilateral Horner’s syndrome in the right eye of a cat. Les diagnostics auxiliaires incluent l’examen otoscopique, des radiographies thoraciques ou une imagerie avancée. Plusieurs étiologies ont été signalées pour le syndrome de Horner, mais la maladie idiopathique est la plus commune. La phényléphrine topique 1 % permet l’identification d’un syndrome de Horner postganglionnaire. L’application topique de cocaïne est le test de référence pour la différenciation du syndrome de Horner des autres causes de miose. Le neurone postganglionnaire/de troisième ordre se déplace de ce ganglion jusqu’à l’orbite. Le neurone préganglionnaire/de deuxième ordre provient des trois premiers segments thoraciques de la colonne vertébrale et se déplace dans le thorax et la région cervicale jusqu’à la synapse au ganglion cervical crânien. Le neurone central/de premier ordre provient de l’hypothalamus et s’étend vers le bas sur la colonne vertébrale. La voie oculo-sympathique est une voie à trois neurones. Elle a été reconnue chez une grande variété de races et d’âges chez les patients petits animaux. Le syndrome de Horner provient d’une dysfonction de la voie oculo-sympathique et est caractérisée par la miose, l’enophtalmie, la protrusion de la troisième paupière et la ptose. Treatment and prognosis are determined by the etiology.Įxamen du syndrome de Horner chez les petits animaux. Ancillary diagnostics include otoscopic examination, thoracic radiographs, or advanced imaging. Numerous etiologies have been reported for Horner’s syndrome, but idiopathic disease is most common. Topical 1% phenylephrine allows for identification of a post-ganglion Horner’s syndrome. Topical application of cocaine is the gold standard for differentiating Horner’s syndrome from other causes of miosis. The postganglionic/third order neuron travels from this ganglion to the orbit. 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 central/first order neuron arises from the hypothalamus and extends down the spinal cord. The oculosympathetic pathway is a 3-neuron pathway. It has been recognized in a wide variety of breeds and ages in small animal patients. Horner’s syndrome arises from dysfunction of the oculosympathetic pathway and is characterized by miosis, enophthalmos, protrusion of the third eyelid, and ptosis.
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