title: Neuropharmacological lesion localization in idiopathic Horner's syndrome in Golden Retrievers and dogs of other breeds.
abstract: OBJECTIVE
  To investigate whether idiopathic Horner's syndrome (HS) in Golden Retrievers is an exclusively preganglionic disorder based on denervation hypersensitivity pharmacological testing with phenylephrine.
  
  
  METHODS
  Medical records of dogs presented with HS between 2000 and 2012. Dogs presented with additional ocular or systemic signs were excluded.
  
  
  METHODS
  Clinical data examined included age, sex, duration of clinical signs, ancillary diagnostic test results, and time to mydriasis on topical ocular application of 1% phenylephrine. Lesions were diagnosed as postganglionic (mydriasis within 20 min) or preganglionic (mydriasis between 20 and 45 min).
  
  
  RESULTS
  Medical records of 21 dogs of nine different breeds were included. An etiopathogenesis for Horner's syndrome was determined in five dogs, none of which were Golden Retrievers. All diagnoses correlated with pharmacological lesion localization. Ten Golden Retrievers were included (eight male and two female) with a mean age of 8.5 years (range: 4-13). Lesion localization was diagnosed as postganglionic in eight (mean: 10 min [range: 6-18]) and preganglionic in two Golden Retrievers (20 and 24 min). All cases were unilateral and had completely resolved within 15 weeks (range: 11-20). Recurrence was not reported in any of the patients.
  
  
  CONCLUSIONS
  Idiopathic postganglionic HS was diagnosed in eight of 10 Golden Retrievers contradicting previous reports of a purely preganglionic localization. Etiopathogenesis of canine idiopathic HS remains to be determined; nevertheless, a vascular etiology cannot be excluded. Future studies using magnetic resonance angiography may aid in clarifying the pathogenesis.
authors.affiliation: Dick White Referrals, Six Mile Bottom, Cambridgeshire, CB8 0UH, UK.
authors.forename: Katherine M
authors.initials: KM
authors.lastname: Simpson
authors.forename: David L
authors.initials: DL
authors.lastname: Williams
authors.forename: Giunio B
authors.initials: GB
authors.lastname: Cherubini
mesh_terms: D000818:Animals; D001339:Autonomic Fibers, Preganglionic / Q000187:drug effects / Q000473:pathology; D001763:Blepharoptosis / Q000175:diagnosis / Q000473:pathology / Q000662:veterinary; D004283:Dog Diseases / Q000175:diagnosis / Q000473:pathology*; D004285:Dogs; D005260:Female; D006732:Horner Syndrome / Q000175:diagnosis / Q000473:pathology / Q000662:veterinary*; D008297:Male; D015877:Miosis / Q000175:diagnosis / Q000473:pathology / Q000662:veterinary; D010656:Phenylephrine / Q000494:pharmacology; D013045:Species Specificity; D017779:Sympathetic Fibers, Postganglionic / Q000187:drug effects / Q000473:pathology; D013566:Sympathomimetics / Q000494:pharmacology
chemical_list: D013566:Sympathomimetics; D010656:Phenylephrine
keywords: Golden Retriever; Horner's syndrome; idiopathic; phenylephrine; postganglionic