Abstract
Short-lasting unilateral neuralgiform headache with conjunctival injection and tearing (SUNCT) is a syndrome characterized by very brief unilateral orbital or periorbital attacks of pain of moderate to severe intensity, which are accompanied by simultaneous ipsilateral cranial autonomic symptoms, mainly conjunctival injection and lacrimation (1, 2). The frequency of attacks can range from one to >100 crises per day and pain may be precipitated by manoeuvres of the neck or from cutaneous trigger zones mainly in a trigeminal topography (1, 3, 4).
Various treatments have been tried for SUNCT syndrome with no or only slight to moderate benefit. Of the antineuralgic drugs, carbamezapine has been tried with only half of patients having a slight to moderate response (5–17). Oxcarbazepine has never been reported in the treatment of SUNCT syndrome (3). We present a patient with SUNCT who responded dramatically to treatment with low-dose oxcarbazepine.
Case report
A 57-year-old white female patient presented to our headache out-patient clinic with a 1-year history of pain attacks in the left periorbital region. At the beginning the pain attacks had continued for 3 months, after which they had disappeared for a further 3 months but recurred and had been troubling her for 8 months without remission. The attacks tended to recur four to five times daily but never occurred during sleep. The pain attack consisted of a brief, sharp stab of moderate to severe intensity which lasted 5 s and was always restricted to the left periorbital region. It could be precipitated by washing the face or sometimes even touching the face.
All attacks were accompanied by ipsilateral conjunctival injection, nasal congestion and lacrimation, which were invariable accompanying symptoms right from the first attack.
When she admitted to our hospital she had been diagnosed as having trigeminal neuralgia at another hospital and had been started on oxcarbazepine 2 × 300 mg/day. She had responded dramatically to this treatment with cessation of her attacks from the first day of treatment. After a few weeks of complete remission she had forgotten to take her pills once, which caused an immediate recurrence, making her panic and seek a second opinion.
Her neurological and clinical examinations were normal, as were personal and family history. Cranial magnetic resonance imaging as well as routine blood tests revealed no abnormality.
The patient was diagnosed as SUNCT syndrome and, because of the history of excellent response, restarted on oxcarbazepine 2 × 300 mg/day. The next day the attacks dissappeared completely. After 1 month she was still pain free. After that she confessed that she had forgotten to take her pills again for a day and the attacks had recurred. Just after she restarted the treatment, the attacks ceased again.
Discussion
Although SUNCT syndrome is a distinct entity, it is very rare and should be differentiated from some other pain disorders. As in the other trigeminal autonomic cephalalgias, cluster headache and paroxysmal hemicrania, the pain is located orbitally and is of severe intensity accompanied by autonomic symptoms. SUNCT is more easily differentiated from the other trigeminal autonomic cephalalgias due to its very short duration. Although brief attacks of paroxysmal hemicrania may last as little as 2 min, attacks of SUNCT usually last <1 min. Pain in both cluster headache and paroxysmal hemicrania is described as boring while it is stabbing in SUNCT. Response to indomethacin may easily distinguish SUNCT and paroxysmal hemicrania (4). Of the very brief headache syndromes, idiopathic stabbing headache is never associated with cranial autonomic features and the pain site varies between attacks and is therefore easily ruled out (4).
Trigeminal neuralgia of the ophthalmic branch is also a rare disorder but may pose a challenge in the differential diagnosis of SUNCT. Both headache disorders are of brief duration, high attack frequency and occur in the same area, mainly unilaterally. SUNCT lasts usually somewhat longer than trigeminal neuralgia, with attacks ranging from 5 to 250 s (18), whereas in trigeminal neuralgia attacks generally last <5 s (19). Very short attacks of SUNCT are rare (18). Trigger zones are common in both disorders. SUNCT as well as trigeminal neuralgia may include periods of remission (4, 19). Spreading of the pain to the lower trigeminal branches is common in trigeminal neuralgia, whereas the pain is generally localized in SUNCT (19).
Although cranial autonomic symptoms have occasionally been reported with trigeminal neuralgia, they are mainly a invariable and diagnostic feature of SUNCT (3, 4, 19, 20). When present, autonomic symptoms in trigeminal neuralgia are usually only minor, with lacrimation being the most frequent symptom (19). In patients with V1 neuralgia and autonomic symptoms, the latter tend to occur only in the later stages of the disease and mainly during severe attacks (19, 20).
Although our case may be mistaken for trigeminal neuralgia of the first branch rather than SUNCT due to the very brief (5 s) duration of the attacks, the invariable presence of lacrimation, conjunctival injection and congestion from the beginning strongly favours the diagnosis of SUNCT.
No uniformly effective therapy has been reported for SUNCT syndrome. Indomethacin, which has dramatic effect in other trigeminal autonomic cephalgias, is useless, and corticosteroids and many other drugs, used effectively to treat cluster headache, are of only occasional benefit (3). Antineuralgic drugs have also been tried in SUNCT syndrome, mainly due to its resemblance to trigeminal neuralgia. Carbamezapine was only slightly to moderately effective in half of patients (5–17). Phenytoin (6, 10, 16), baclofen (5, 6, 16), clonazepam (5, 9, 16) and valproic acid (6, 16) were also of no, or occasional slight benefit. Recently, better results have been obtained with lamotrigine (17, 21, 22) and gabapentin (12, 23) with complete remission in some patients, but the case numbers are low.
To our knowledge, oxcarbazepine has not previously been tried in SUNCT syndrome (3). Our patient showed a dramatic response to low doses of oxcarbazepine. We ruled out the possibility of a spontaneous remission because the drug was stopped twice, always leading to a recurrence of the attacks. Reinstitution of the drug reproduced the same dramatic relief. It is difficult to explain this dramatic effect of oxcarbazepine in SUNCT, bearing in mind that trials of carbamezapine, a closely similar drug, failed to show significant effect. It is possible that oxcarbazepine may act through a different mechanism than carbamezapine in SUNCT, but until this effect of oxcarbazepine has been reproduced in a larger number of cases, our case can be regarded only as an occasional responder to the drug.