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

Management. All acute Horner syndrome presentations should be referred for same-day evaluation to rule out potentially life-threatening conditions, such as a cerebrovascular accident, carotid artery dissection or aneurysm, and giant cell arteritis.¹⁰ The urgent evaluation should include CTA and MRI/MRA of the head and neck.⁵ If giant cell arteritis is suspected, it is also recommended to obtain urgent bloodwork, which should include complete blood count with differential, erythrocyte sedimentation rate, and C-reactive protein.⁵ Carotid angiography and CT of the chest also are indicated if the aforementioned tests are noncontributory, but these are less urgent and can be deferred for evaluation within 1 to 2 days after the initial diagnosis.¹⁰

In this patient’s case, an immediate neurologic evaluation was appropriate due to the acute and painful nature of her presentation. Ultimately, her Horner syndrome was determined to result from an internal carotid artery dissection. As indicated by Schievink, all acute Horner syndrome cases should be considered a result of a carotid artery dissection until proven otherwise, despite the presence or absence of any other signs or symptoms.¹¹ This consideration is not only because of the potentially life-threatening sequelae associated with carotid dissections, but also because dissections have been shown to be the most common cause of ischemic strokes in young and middle-aged patients, accounting for 10% to 25% of all ischemic strokes.^4,11

Carotid Artery Dissection

An artery dissection is typically the result of a tear of the tunica intima of the arterial wall, which leads to a leakage of blood into the potential space between the artery’s walls.^12,13 As the arterial blood pressure forces blood through the tear, an intramural hematoma, or false lumen, is formed within the layers of the tunica media.¹⁴ The hematoma can form as a subintimal dissection, which tends to result in arterial lumen stenosis, or a subadventitial dissection, leading to aneurysmal dilation resulting in partial or complete blockage of the affected artery.¹⁴ Additional complications resulting from carotid artery dissections can include complete vascular occlusion or thrombus formation, resulting in a cerebrovascular accident. Additionally, subarachnoid hemorrhages may result if the carotid artery ruptures due to compromised vessel wall integrity.¹¹

There are many causes of carotid artery dissections, such as structural defects of the arterial wall, fibromuscular dysplasia, cystic medial necrosis, and connective tissue disorders, including Ehlers-Danlos syndrome type IV, Marfan syndrome, autosomal dominant polycystic kidney disease, and osteogenesis imperfecta type I.¹³ Many environmental factors also can induce a carotid artery dissection, such as a history of anesthesia use, resuscitation with classic cardiopulmonary resuscitation techniques, head or neck trauma, chiropractic manipulation of the neck, and hyperextension or rotation of the neck, which can occur in activities such as yoga, painting a ceiling, coughing, vomiting, or sneezing.¹¹

Patients with an internal carotid artery dissection typically present with pain on one side of the neck, face, or head, which can be accompanied by a partial Horner syndrome that results from damage to the oculosympathetic neurons traveling with the carotid plexus in the internal carotid artery wall.^9,10 Unilateral facial or orbital pain has been noted to be present in half of patients and is typically accompanied by an ipsilateral headache.⁹ These symptoms are typically followed by cerebral or retinal ischemia within hours or days of onset and other ophthalmic conditions that can cause blindness, such as ischemic optic neuropathy or retinal artery occlusions, although these are rare.⁹