Bilateral agenesis of the internal carotid artery: case report and approach to management.

We present the case of a 13-year-old boy who presented with two episodes of acute onset severe headache. Initial investigation with computerised tomography revealed no apparent abnormality. Magnetic resonance imaging and magnetic resonance angiography revealed that this boy had absence of both internal carotid arteries bilaterally. Absence of the internal carotid arteries is an uncommon condition, but does occur with unilateral absence being more common than bilateral absence. The condition is usually diagnosed in adulthood but may be diagnosed incidentally in childhood. When diagnosed in childhood, the main aim of management is to prevent the development of cerebrovascular accidents.