Another type of unusual facial pain which initially may be thought to be temporal arteritis is that caused by spontaneous dissection of the carotid and/or vertebral arteries.{204} The vascular dissection may occur spontaneously, especially in those with unsuspected fibromuscular dysplasia. Carotid and/or vertebral artery dissection may follow head and neck injury is in "whiplash", blows to the neck, and following neck manipulation. The clues to making the diagnosis include pain over the angle of the jaw and hemicranium, oculosympathetic paresis, dysgeusia, and altered facial sensation, as in the following case: A 46-year old mildly hypertensive woman developed "lightening pains" that radiated to her face from the left side of her neck. The following day the pain had become dull and was localized behind her left eye. She noted slight drooping of her left eyelid, a strange persistent metallic taste, and discomfort over the left side of her forehead. Her unilateral neck and face pain then increase in intensity, and the entire left side of her face became "numb and disagreeable." Examination showed a left oculosympathetic paresis and marked decrease in sensation to light touch and pinprick over all three divisions of the left trigeminal nerve. Testing facial sensation evoked an unpleasant sensation. The remainder of her examination was normal as were CT and MRI. Cerebral angiography demonstrated a dissection of the left internal carotid artery extending intracranially to the cavernous sinus and a 2 cm dissection of the left vertebral artery.{205} Carotid dissection can mimic Raeder's paratrigeminal syndrome (see above), but requires angiography for diagnosis.