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The prevalence is estimated at approximately 1 in 15,000. It is slightly more predominant in males (male-to-female ratio of 1.5:1), with a mean age of onset of around 50 years. A few cases of SUNCT/SUNA syndrome have been reported in children.

The disease manifests with strictly unilateral pain attacks of moderate-to-severe or very severe intensity. The pain is described as throbbing, sharp or stabbing. It usually involves the ophthalmic division of the trigeminal nerve and, less commonly, may involve any part of the head. In the majority of cases, the pain attacks are triggered by cutaneous stimuli (and not by alcohol or nitroglycerin). Spontaneous attacks have also been described. The typical SUNCT/SUNA patient may have 50 to 100 short attacks a day, lasting for 1 to 5 minutes. The attacks predominate during the daytime. Prominent, ipsilateral conjunctival injection and lacrimation regularly accompany the attacks. Nasal stuffiness and rhinorrhea are frequent.

Etiopathology remains unclear. Trauma, arteriovenous malformations and pituitary adenomas may have a causative role.

The diagnosis is made after a careful history with attention to the features of the disorder as set out in the International Classification of Headache Disorders, 3rd Edition, careful physical examination and relevant investigations. Particular features of note are the relative brevity of lateralised attacks, their triggerability and the absence of a refractory period to stimulation.

Trigeminal neuralgia is the major differential diagnosis. It is very important to differentiate SUNCT/SUNA syndrome from other trigeminal autonomic cephalgias such as cluster headache and paroxysmal hemicrania, as each of these syndromes have a highly selective response to treatment.

There is no cure for SUNCT/SUNA syndrome. Patients may benefit from administration of lamotrigine, topiramate, gabapentin or carbamazepine. Oxygen, anaesthetic blockades, and sumatriptan or indomethacin therapies, known to be effective in other trigeminal autonomic cephalgias, have little or no effect in SUNCT syndrome. In severe cases, surgical techniques, such as microvascular trigeminal nerve root decompression, have been considered.

The prognosis is guarded in that most patients will continue to have attacks over many years.