This 3 year old male neutered Golden Retreiver was referred after having been seen with a sunken right globe. The tentative diagnosis was Horner’s syndrome. What are the other signs pathognomonic of the condition and what would be the procedure to make a definitive diagnosis?
The dog has indeed got Horner’s syndrome, with a miotic pupil, ptosis and enophthalmos characterised by third eyelid protrusion. This is common in Golden Retrievers and can be temporarily ameliorated by use of topical 0.1% phenylephrine, an adrenergic agonist. Rapid resolution of signs as occurred in this dog, shows that the third order neurone is affected with denervation hypersensitivity manifest at the motor end plate of the nerve.