Carotid artery dissection presenting as a painless Horner's syndrome in a pilot: fit to fly?

We describe a case of a middle-aged Caucasian pilot who presented to us with a painless left Horner's syndrome due to a focal dissection of the infra-petrous portion of the ipsilateral internal carotid artery. He did not suffer symptoms of cerebral ischemia at the time of onset, or during the following 2 yr. The Horner's syndrome persisted unchanged throughout follow-up. Serial magnetic resonance angiograms showed some regression of the focal stenosis at 12 mo, with no further change over the next 10 mo. The literature suggests that the risk of stroke after onset of dissection is usually in the first month, and the risk of recurrence of dissection is about 1% per year after the first year. Our patient was prescribed aspirin 300 mg.d-1, and certified to fly as or with a co-pilot commencing 1 yr after onset of his symptoms.