[Traumatic internal carotid artery dissection associated with triathlon: a rare differential diagnosis].

Most cervical artery dissections occur spontaneously, but traumatic mechanisms can occasionally be identified. Traumatic internal carotid artery dissection has been attributed with several sports, but there are no reports of its occurrence in thriathlon. We report the case of a 63-year-old semi-professional triathlete, who noticed right-sided neck pain and parietooccipital headache after a triathlon competition. Neurological examination revealed an incomplete right Horner's syndrome. MRI and MR-angiography demonstrated a right-sided internal carotid artery dissection with segmental loss of flow-signal and a mural haematoma in the vessel wall. In this case two pathophysiological mechanisms may be considered. Our patient reported receiving several blows to the neck in a congested 50-metre pool during the triathlon swimming stage. Furthermore, the hyperextended position of the neck during the subsequent cycling stage may have contributed, to a large extent, to the arterial dissection. The risk factors, presenting symptoms, diagnosis of internal carotid artery dissection are reviewed.