Facial pain in MS: When to think of trigeminal autonomic cephalalgia

Giuliani and colleagues report a patient with multiple sclerosis (MS) who developed short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT). The patient had a demyelinating lesion in the pons close to the trigeminal root entry zone and responded to treatment with lamotrigine. ¹

SUNCT is a rare headache syndrome classed as a trigeminal autonomic cephalalgia (TAC). This group of disorders also includes cluster headache, paroxysmal hemicrania and hemicrania continua, which have shared features of unilateral head pain associated with ipsilateral cranial autonomic symptoms. The TACs are distinguished from each other by their attack length and treatment response, and SUNCT has the shortest attacks, lasting 1–600 seconds. ²

SUNCT also has clinical, radiological and therapeutic overlap with trigeminal neuralgia (TN). Patients with MS are thought to have a 20-fold increased risk of TN. ³ SUNCT is far rarer than TN, and epidemiological studies have not been able to assess whether its risk is also increased in MS. Both TN and SUNCT cause severe neuralgiform pain in the trigeminal distribution, may be associated with pontine lesions and/or trigeminal neurovascular conflict, and frequently respond to sodium-channel blocking medications. Other than the presence of cranial autonomic symptoms, in comparison to TN, SUNCT is more likely to affect the first division of the trigeminal nerve, less likely to have a refractory period after triggered pain and more likely to be associated with background pain. ⁴

Randomised controlled trials for treatment of SUNCT have not been performed, but open label evidence suggests that lamotrigine is the most effective medical treatment and should be considered first line if there are no contraindications. ⁵ Alternatives are carbamazepine, oxcarbazepine, duloxetine, topiramate, pregabalin and gabapentin. In refractory patients with neurovascular conflict, microvascular decompression can be considered. Occipital nerve stimulation and deep brain stimulation are promising alternatives for medically intractable patients.