title: Positive Apraclonidine Test in Horner Syndrome Caused by Thalamic Hemorrhage.
abstract: Reversal of anisocoria following instillation of apraclonidine 0.5% has been reported in Horner syndrome caused by lesions of the central and peripheral nervous system. The shortest documented latency between symptom onset and a positive apraclonidine test is 36 hours, occurring in a patient with a pontomedullary infarct. We present the case of a 69-year-old man with Horner syndrome due to thalamic hemorrhage in whom apraclonidine testing demonstrated reversal of anisocoria 4 days after symptom onset. This is the first reported case of a positive apraclonidine test in a Horner syndrome caused by a lesion at this site. It suggests that apraclonidine testing is useful in confirming the diagnosis within days of onset even in a lesion located at the most proximal portion of the oculosympathetic pathway.
authors.affiliation: Department of Ophthalmology and Visual Sciences, Kellogg Eye Center, University of Michigan, Ann Arbor, Michigan.
authors.forename: Courtney Y
authors.initials: CY
authors.lastname: Kauh
authors.forename: Lulu L C D
authors.initials: LL
authors.lastname: Bursztyn
mesh_terms: D000368:Aged; D003000:Clonidine / Q000031:analogs & derivatives* / Q000378:metabolism; D003941:Diagnostic Techniques, Ophthalmological; D006470:Hemorrhage / Q000150:complications*; D006732:Horner Syndrome / Q000175:diagnosis* / Q000209:etiology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D013786:Thalamic Diseases / Q000150:complications*
chemical_list: C016986:apraclonidine; D003000:Clonidine