ABSTRACT
Trigeminal autonomic cephalgias (TACs) consist of a group of headache syndromes marked by head pain in the distribution of the trigeminal nerve with cranial autonomic activation. This chapter is concerned with two other TACs: paroxysmal hemicrania and short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT). Patients with chronic paroxysmal hemicrania (CPH) are reported to have reduced pain thresholds, reduced comeal reflex thresholds, and normal blink reflexes. Magnetic resonance imaging (MRI) studies of patients with CPH have been normal, but segmental narrowing of ophthalmic veins on orbital phlebography has been reported. The differential diagnosis of paroxysmal hemicrania (PH) includes the other primary short-lasting headaches and the secondary causes of PH. Orbital phlebography is reported to be abnormal in patients with SUNCT, with a narrowed superior ophthalmic vein homolateral to the pain. SUNCT typically has prominent cranial autonomic symptoms, such as tearing and conjunctival injection, which has been proposed to be activation of the trigeminal-autonomic reflex.
