Dante Valer, Hernan Canari and Alejandro Escalaya
Horner syndrome is a constellation of neurological findings consisting of ipsilateral ptosis, miosis and anhidrosis. Partial Horner syndrome, comprising ipsilateral ptosis and miosis in the absence of anhidrosis, is a well-documented but uncommon manifestation of internal carotid artery dissection. Internal carotid artery dissection (ICAD) is a rare entity that either results from traumatic injury or can be spontaneously preceded or not by aminor trauma such as sporting activities, is a common cause of ischaemic stroke in young patients. As many as 40 to 50% of patients with carotid dissection will develop an ipsilateral Horner’s síndrome.