Trigeminal autonomic cephalalgia

Trigeminal Autonomic Cephalalgia

Trigeminal autonomic cephalalgias (TACs) are a group of primary headache disorders characterized by unilateral head pain associated with ipsilateral cranial autonomic symptoms. These conditions are distinguished by their clinical features, including the duration and frequency of headache attacks, as well as the presence of autonomic symptoms such as lacrimation, nasal congestion, and ptosis.

Classification

TACs are classified into several distinct disorders, each with unique characteristics:

• Cluster headache: Known for severe, unilateral pain typically around the eye, with attacks lasting 15 to 180 minutes. Cluster headaches often occur in bouts or "clusters" lasting weeks to months, followed by remission periods.

• Paroxysmal hemicrania: Characterized by shorter, more frequent attacks of severe unilateral pain, often around the eye, lasting 2 to 30 minutes. These attacks respond well to indomethacin.

• Short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT): Involves very short attacks of unilateral pain, lasting 1 to 600 seconds, accompanied by prominent autonomic features such as conjunctival injection and tearing.

• Hemicrania continua: A continuous, unilateral headache with superimposed exacerbations of severe pain, which also responds to indomethacin.

Pathophysiology

The pathophysiology of TACs is not fully understood, but it is believed to involve the trigeminal nerve and the autonomic nervous system. The trigeminal nerve is responsible for sensation in the face and motor functions such as biting and chewing. In TACs, there is activation of the trigeminal-autonomic reflex, leading to the characteristic autonomic symptoms.

Neuroimaging studies have shown activation of the hypothalamus during attacks of cluster headache, suggesting a central role in the pathogenesis of these disorders.

Diagnosis

Diagnosis of TACs is primarily clinical, based on the history and characteristics of the headache attacks. The International Classification of Headache Disorders (ICHD) provides criteria for diagnosing each type of TAC. Neuroimaging may be used to rule out secondary causes of headache.

Treatment

Treatment of TACs varies depending on the specific disorder:

• Cluster headache: Acute treatment includes oxygen therapy and triptans. Preventive treatments include verapamil, lithium, and corticosteroids.

• Paroxysmal hemicrania: Indomethacin is the treatment of choice and is often diagnostic.

• SUNCT: Treatment can be challenging, but options include lamotrigine, topiramate, and gabapentin.

• Hemicrania continua: Indomethacin is effective in most cases.

Prognosis

The prognosis of TACs varies. Cluster headaches can be chronic or episodic, with periods of remission. Paroxysmal hemicrania and hemicrania continua typically respond well to indomethacin, while SUNCT can be more refractory to treatment.

Also see

• Migraine
• Tension-type headache
• Neuralgia
• Headache disorders