Trigeminal autonomic cephalalgia

Trigeminal autonomic cephalalgia (TAC) refers to a group of primary headache disorders characterized by unilateral head pain occurring in the distribution of the trigeminal nerve, accompanied by prominent ipsilateral cranial autonomic features. This group includes cluster headache, paroxysmal hemicrania, short-lasting unilateral neuralgiform headache attacks (SUNCT/SUNA), and hemicrania continua. The autonomic symptoms that accompany the headache attacks include conjunctival injection (eye redness), lacrimation (tearing), nasal congestion or rhinorrhea, eyelid edema, forehead and facial sweating, miosis (pupil constriction), and ptosis (drooping eyelid), all occurring on the same side as the pain. The underlying pathophysiology involves activation of the trigeminovascular system and the trigeminal-autonomic reflex, with involvement of the hypothalamus playing a central role, particularly in the circadian and circannual periodicity seen in cluster headache. The pain is typically severe to excruciating and can be debilitating, significantly affecting quality of life. TACs primarily affect the nervous system, specifically the trigeminal sensory pathways and parasympathetic autonomic pathways. Treatment varies depending on the specific TAC subtype. Cluster headache is treated acutely with high-flow oxygen and subcutaneous sumatriptan, with verapamil being the most commonly used preventive agent. Paroxysmal hemicrania shows an absolute response to indomethacin, which is considered a diagnostic criterion. SUNCT/SUNA may respond to lamotrigine, and hemicrania continua also responds to indomethacin. Greater occipital nerve blocks and, in refractory cases, neurostimulation techniques (such as occipital nerve stimulation or sphenopalatine ganglion stimulation) may be considered. Early and accurate diagnosis is essential, as each subtype has distinct treatment approaches.

Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.

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