Abstract
Oculosympathetic paresis, historically known as Horner sydrome, classically results in a triad of ptosis, miosis, and anhydrosis on the affected side. Any interruption or insult to any part of the sympathetic pathway to the eye can result in these classic findings. There are many possible etiologies along the three-neuron pathway, however, a few potentially life threatening causes must always be ruled out, especially in acute presentations. One life threatening etiology, in particular, to rule out is of internal carotid artery dissection (ICAD). A 38-year-old white female was referred to our clinic for a second opinion by her primary care physician for a sudden onset headache, ptosis, and miosis of the left side following a short endurance race 24–48 h prior. Entering visual acuities were 20/20 in the right eye (OD) and 20/20 in the left eye (OS). Emergent magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) revealed a severe left ICAD. The patient was started on oral anticoagulants and oral steroids. Spontaneous resolution occurred three months later upon confirmation with repeat MRI/MRA. This case report reviews the clinical findings, diagnoses, treatment, and management of patients with Horner syndromes secondary to ICAD.