Carotid artery thrombosis and delayed stroke associated with the use of a shoulder belt in a teenager.

Blunt carotid artery injury caused by shoulder belts is rare and requires a high index of suspicion to diagnose before the onset of neurologic sequelae. Neurologic abnormalities may be erroneously attributed to concomitant head trauma, and the onset of neurologic abnormalities may be delayed for hours or days. The case of a young, teenaged driver with a "seatbelt sign" and presentation of signs and symptoms of carotid artery thrombosis 13 days after injury is described. Occult vascular injury should be suspected if neurologic deterioration occurs after a lucid interval and/or computed tomography of the head is inconsistent with neurologic findings. Screening criteria and possible screening modalities are discussed.