Trigeminal autonomic cephalalgia

Trigeminal autonomic cephalalgia (TAC) is a primary headache disorder characterized by severe unilateral cranio-facial pain associated with autonomic features of parasympathetic overactivity or sympathetic underactivity on that side. TAC should not be the final diagnosis, because the treatments differ for the different types. TAC is differentiated according to the number of pain-free days, the frequency, and the duration of episodes. Hemicrania continua (HC) is characterized by the absence of pain-free days. Cluster headache (CH), paroxysmal hemicrania (PH), and SUNCT/SUNA follow in order of decreasing duration and/or increasing frequency. Brain MRI imaging with contrast is mandatory for TACs because a number of patients could have a structural disorder, primarily a pituitary or posterior fossa lesion. The treatment is unique for each type with HC and PH considered to be indomethacin responsive and CH and SUNCT requiring different approaches.