Acute Painful Horner Syndrome as the First Presenting Sign of Carotid Artery Dissection.

Background: Horner syndrome is a rare neurologic disorder that can arise from severe neurologic and systemic conditions, which may require immediate diagnosis with radiologic imaging and treatment with antiplatelet and anticoagulant therapy. Horner syndrome is often asymptomatic but can have distinct, easily identified characteristics seen with an ophthalmic examination.

Case presentation: A 61-year-old woman presented with periorbital pain localized around and behind the right eye that she rated as 7 on a 10-point scale with onset 3 days prior. She reported light sensitivity, syncope, dizziness, and a recent history of transient ischemic attacks of unknown etiology. The patient had acute, slight ptosis with pathologic miosis and pain in the ipsilateral eye with no reports of exposure to miotic pharmaceutical agents and no history of trauma to the globe or orbit eliminated other differentials, leading to a diagnosis of right-sided Horner syndrome. She was referred for emergency department evaluation where radiography was indicative of an internal carotid artery dissection.

Conclusions: Due to possible life-threatening complications that can arise in patients with Horner syndrome, clinicians must have a thorough understanding of the condition, appropriate treatment, and management modalities. Determining the underlying etiology of Horner syndrome can help prevent a decrease in a patient's vision or quality of life and in some cases prevent death. Magnetic resonance imaging and computed tomography should be used to rule out carotid artery dissection and other severe conditions.