Purpose: To highlight that internal carotid artery dissection is a common cause of Horner's syndrome and that it is important to diagnose dissection as anticoagulation can prevent carotid thrombosis and embolism.
Methods: Five case reports are presented of patients with Horner's syndrome secondary to carotid dissection. One patient had carotid dissection secondary to trauma, two had spontaneous dissections and two had dissections in the settings of other illness. A literature search was performed on carotid dissection as a cause of Horner's syndrome and its diagnosis and management.
Results: The case reports and literature highlight that dissection is under-recognized as a cause of Horner's syndrome and can be missed. The investigation of choice is a magnetic resonance imaging and angiography scan of the head and neck. The treatment advocated is anticoagulation for 3-6 months.
Conclusion: Carotid dissection should be suspected in patients with Horner's syndrome, particularly if head or neck pain is present.