Carotid Artery Dissection occurs when there is a disruption in the tunica media allowing blood, under arterial pressure, to dissect along the rent media or between the media and adventitia. This most commonly occurs with trauma although there may be an underlying arteriopathy such as fibromuscular dysplasia or Marfan's syndrome. These conditions can cause "spontaneous" dissection. The causative trauma can be as slight as chiropractic manipulation.

The sequelae of dissection can be life threatening, such as occlusion, pseudoaneurysm, and thromboembolism. Mortality approaches 75%. The most common symptoms are headache and TIA or stroke symptoms. Unilateral Horners syndrome occurs in up to 50% of patients. Since dissection often occurs in younger patients (under 40) a high index of suspicion is often needed to prevent the serious sequelae listed above.

Magnetic resononance angiography, computed tomographic angiography, and digital subtraction angiography all can be helpful in making the diagnosis. In general a long segement smooth narrowing of the lumen suggests the diagnosis. Non contrast CT and T1 weighted MR can demonstrate intramural clot.

Treatment includes anticoagulation and carotid artery ligation. These treatments are employed as necessary with the goal of preventing the high morbidity and mortality associated with the sequelae of the dissection.