Trigeminal autonomic cephalgia

Trigeminal Autonomic Cephalalgias (TACs) are a group of primary headache disorders characterized by unilateral head pain associated with ipsilateral cranial autonomic features. The term "trigeminal" refers to the trigeminal nerve, which is responsible for sensation in the face and motor functions such as biting and chewing; "autonomic" refers to the part of the nervous system that controls involuntary body functions, and "cephalgia" means head pain. The most well-known conditions classified under TACs include Cluster Headache, Paroxysmal Hemicrania, and SUNCT Syndrome (Short-lasting Unilateral Neuralgiform headache attacks with Conjunctival injection and Tearing).

Symptoms and Diagnosis

TACs are marked by severe, unilateral head pain that is typically located around the orbital, supraorbital, or temporal areas. The pain is often described as sharp, stabbing, or burning. Autonomic symptoms may include redness of the eye (conjunctival injection), tearing (lacrimation), nasal congestion or runny nose (rhinorrhea), eyelid swelling (edema), forehead and facial sweating, miosis (constricted pupil), ptosis (drooping eyelid), and a sense of restlessness or agitation.

Diagnosis of TACs is primarily clinical, based on the patient's history and the characteristic features of the headaches. Neuroimaging tests, such as MRI or CT scans, are typically performed to rule out secondary causes of headache.

Treatment

Treatment of TACs focuses on both acute attacks and preventive therapy. Acute treatments include oxygen therapy, particularly for cluster headaches, and triptans. Preventive treatments may involve medications such as verapamil, lithium, and corticosteroids. In refractory cases, surgical interventions such as occipital nerve stimulation or deep brain stimulation may be considered.

Epidemiology

TACs are relatively rare, with cluster headaches being the most common among them. These conditions are more prevalent in men than in women, particularly in the case of cluster headaches, which have a male to female ratio of about 2.5:1.

Pathophysiology

The exact pathophysiology of TACs is not fully understood, but it is believed to involve activation of the trigeminal-autonomic reflex. This reflex is a connection between the trigeminal nerve and the autonomic nervous system, leading to the characteristic pain and autonomic symptoms of TACs. Hypothalamic involvement has also been suggested, particularly in cluster headaches, given the circadian and circannual rhythms observed in these disorders.

See Also

• Headache
• Migraine
• Trigeminal Nerve
• Autonomic Nervous System