Positive Apraclonidine Test 36 Hours After Acute Onset of Horner Syndrome in Dorsolateral Pontomedullary Stroke

Abstract

A 40-year-old man developed a Horner syndrome as part of a dorsolateral medullary brainstem infarction. Thirty-six hours after the onset of the stroke, topical instillation of 0.5% apraclonidine produced reversal of anisocoria. This is the first case in which apraclonidine testing has been applied to a patient with a Horner syndrome caused by a lesion in the first segment of the oculosympathetic pathway and the shortest reported interval between clinical manifestations of the lesion and apraclonidine-induced reversal of anisocoria. A review of all reported cases of apraclonidine testing in Horner syndrome suggests that this is a promising diagnostic adjunct that must be validated in larger studies.

Adult Horner’s syndrome: a combined clinical, pharmacological, and imaging algorithm

“…The overall sensitivity of Apraclonidine is 87%, 11 which is comparable to cocaine testing with a positive test reported within 36 h of onset of symptoms. 12 However, the results are yet to be validated in a large study and there are several reports of false negative tests. 13,14 There are many limitations to the use of Hydroxyamphetamine, with false negative results occurring particularly within the first week of HS onset.…”

Impact of T3 thoracoscopic sympathectomy on pupillary function: a cause of partial Horner’s syndrome?

“…In sympathetic lesions, upregulation of alfa-1 receptors increases sensitivity to apraclonidine. Denervation hypersensitivity results in pupil dilatation and elevation of the eyelid on the abnormal side but without response or slight miosis on the normal side [17,18].…”

Horner syndrome: clinical perspectives

“…Upregulation of the postsynaptic receptors may require a certain amount of time after oculosympathetic paresis, and the concern is that a pupil in an acute Horner syndrome will not dilate in this interim phase 115. However, Lebas et al described a patient who developed a Horner syndrome as part of a dorsal medullary brainstem infarct, and had a positive apraclonidine test 36 hours after the onset of his symptoms 116. Another patient who developed Horner syndrome from a traumatic carotid dissection after a motor vehicle accident had a positive apraclonidine test a mere 3 hours after the onset of his symptoms 117.…”