Trigeminal autonomic cephalgias (TACs)

The concept of a group of headaches whose pathophysiological focus revolves around the trigeminal-autonomic reflex fills a useful gap in characterizing a number of primary headache syndromes. Broadly these syndromes involve activation of trigeminovascular nociceptive pathways with reflex cranial autonomic activation. Clinically, this physiology predicts pain with some combination of lacrimation, conjunctival injection. nasal congestion, or eyelid oedema. Several( of rite primary neurovascular headaches, notably cluster headaches, paroxysmal hemicrania and short-lasting neuralgiform pain with conjunctival injection and tearing (SUNCT), seem to immediately fit this classification. This physiology also explains why some patients with migraine present cranial autonomic features. tmd the concept is thus broadly useful for clinicians seeking a pathophysiological understanding of the primary neurovascular headaches. Given the known pathophysiology one c can place the various treatments aimed nr preventing these headaches or indeed treating the acute attacks, into context.