Trigeminal autonomic cephalalgias: a review

Abstract

Trigeminal autonomic cephalalgias are a group of primary headache disorders presenting as unilateral pain in the somatic distribution of the trigeminal nerve, associated with ipsilateral cranial autonomic symptoms. This clinicopathologic group includes cluster headache, paroxysmal hemicrania, hemicrania continua and short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing/cranial autonomic features, which differ mainly as regards the duration and frequency of pain as well as response to treatment. These disorders are not as rare as they were thought to be and due to the severity of the pain can substantially affect the patients’ quality of life. Many other forms of primary headaches, such as migraine, trigeminal neuralgia and primary stabbing headache, as well as secondary headaches, particularly those caused by pituitary, posterior fossa, orbital, paranasal sinus and vascular pathology, need to be carefully considered in the diagnosis of trigeminal autonomic cephalalgias. Research in this field, particularly using functional neuroimaging, has resulted in a much better understanding of these disorders. Dysfunction in the nociceptive modulatory pathways in brain’s pain matrix is currently thought to produce a permissive state for the occurrence of a trigeminal autonomic cephalalgia attack, with posterior hypothalamus serving as a terminator rather than the generator of the attack. The current treatment strategies include medical and surgical approaches; of the latter, neuromodulation techniques, particularly deep brain stimulation of posterior hypothalamus, have proven to be particularly effective and promising.