Apraclonidine is the most widely used pharmacologic agent to confirm Horner syndrome. It is a strong α-2 and a weak α-1 adrenergic agonist and reversal of anisocoria is considered a positive test. The utility of apraclonidine in acute Horner syndrome remains controversial as the exact timing for denervation sensitivity to develop remains unknown. The goal of this study was to describe the use of apraclonidine in the diagnosis of acute Horner syndrome in patients with an unequivocal onset within 7 days. We identified 3 patients who were referred to ophthalmology/neuro-ophthalmology service and had reversal of anisocoria within 7 days. Two cases of second-order Horner syndrome after cardiac surgery and a case of a third-order Horner syndrome from a carotid cavernous sinus fistula resulted in reversal of anisocoria 72 h, 48 h, and 5 days after onset. Photographic documentation was provided for all cases. Our results suggest that apraclonidine has utility in the acute period and positive results can be seen as early as 48 h after onset. Apraclonidine should therefore still be considered to confirm the presence of acute Horner syndrome before extensive neuroimaging is performed.

中文翻译：

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阿普乐定用于急性霍纳综合征的药理学确认

阿普乐定是最广泛使用的用于确认霍纳综合征的药物。它是一种强 α-2 和一种弱 α-1 肾上腺素能激动剂，并且对等距的逆转被认为是一种阳性测试。阿普乐定在急性霍纳综合征中的应用仍存在争议，因为去神经敏感性发生的确切时间尚不清楚。本研究的目的是描述在 7 天内明确发作的急性霍纳综合征患者中使用阿普可乐定诊断。我们确定了 3 名被转诊至眼科/神经眼科服务并在 7 天内逆转瞳孔不等的患者。两例心脏手术后二阶霍纳综合征病例和一例颈动脉海绵窦瘘引起的三阶霍纳综合征病例在发病后 72 小时、48 小时和 5 天导致异侧斜度逆转。为所有案件提供了照片文件。我们的结果表明，阿可乐定在急性期有效，最早在发病后 48 小时即可看到阳性结果。因此，在进行广泛的神经影像学检查之前，仍应考虑使用安可乐定来确认急性霍纳综合征的存在。