SUNCT Syndrome Responsive to Gabapentin (Neurontin)

Abstract

A 48-year-old male suffering with SUNCT (severe unilateral neuralgiform headache with conjunctival injection and tearing, rhinorrhea and sub-clinical sweating) presented in 1996 after a 10-year history of multiple failed therapies. The symptoms included strictly left-sided ocular, as well as facial and temple pain. The pain attacks were burning, sharp, shooting and occurred 25 times daily, lasting 2 to 3 minutes with tearing and conjunctival injection. There was no associated nausea or vomiting, but there was photophobia. No other autonomic changes were reported and the pain was not triggerable. Initially Indocin (indomethacin) was tried without significant benefit. Gabapentin (Neurontin) was then started with improvement at 1800 mg per day. The patient was then lost to follow-up for 3 years, as he moved from the Los Angeles area. He returned in 1999 having stopped the gabapentin after his prescription ran out in 1996, reporting the pain returned immediately. Again gabapentin was prescribed and at 900 mg three times daily he has been pain free for 12 months.

SUNCT syndrome is described as a pain that is associated with short lasting unilateral neuralgiform headache attacks with conjunctival injection, tearing, rhinorrhea and subclinical sweating. Sjaastad and co-workers in 1978 first described SUNCT (1). Most attacks are reported as moderate to severe, 30–120 second pain paroxysms. Pain is usually localized to the eye and may occur in a cluster fashion with some quiet periods. Attack frequency may be up to 30 per day or many per hour (2, 3). Although SUNCT is clinically well identified it is poorly treated. Carbamazepine may be effective in controlling some symptomatology, but not consistently (3, 4).

Case history

A 48-year-old right-handed male, referred by his internist, presented to the Pain Center, Cedars-Sinai Medical Center in 1996. His complaint described left-sided orbital/facial region pain, as well as pain behind the left ear and temple. He reported the pain was never located on the right side. The pain was intermittent, lasting 2 to 3 minutes, occurring up to 25 times daily. There was associated conjunctival injection and eye tearing. The pain quality was like ‘hot water or an ice pick-like pain’ in the eye, as well as burning, sharp and shooting. There was no associated nausea or vomiting, but there was some photophobia. There were no other autonomic signs and the pain was not triggerable. Aggravating factors were sun and light. There were no alleviating factors.

The patient reported the pain started approximately 10 years prior to the evaluation. He reported he initially saw a neurologist in his local area and a brain CT scan was performed, which was within normal limits. He was told that this was a behavioural problem and that he should learn some relaxation techniques. He was then evaluated by an ophthalmologic clinic and was prescribed Prednisone at 60 mg daily for 4 weeks. He stated that during the 4 weeks on Prednisone he was pain free; however, as soon as the steroid was stopped, the pain returned. He was told that no further treatment could be offered.

The patient then saw a second neurologist, who prescribed carbamazepine, which was taken at therapeutic doses for approximately 6 weeks without benefit. He was also treated with verapamil at 80 mg five times daily for approximately 4 weeks without benefit. An ear, nose and throat specialist diagnosed a maxillary sinusitis and performed a Caldwell-Luc procedure. There was no improvement in symptoms. Following the surgery he was next evaluated at a comprehensive ear institute and underwent allergy testing, as well as audiometric testing – all of which were normal. He underwent further CT sinus scans and a brain MRI; all tests were normal and inconclusive. A third neurologist added psychometric testing, including the Minnesota Multiphasic Personality Inventory, to the compliment of tests performed. There were no elevations. A thermogram, performed by this doctor, revealed a hot region around the left maxilla. Later an MRA was ordered with negative results. He was treated with sumatriptan 6 mg subcutaneously, as well as dihydroergotamine intravenously as well as indomethacin without benefit.

Habit history

Habit history was positive for tooth grinding and clenching. The patient did not wear an intra-oral appliance. There were no temporomandibular symptoms. There was no previous smoking, alcohol or drug use. Sleep was poor, with numerous nocturnal arousals. He denied snoring or apnoea. He consumed approximately three caffeinated drinks daily. He did not perform any specific exercises.

Past medical history

The past medical history was positive for operations including the sinus surgery. There were no known medication allergies.

Review of systems

The review of systems was essentially within normal limits.

Current medications

Tylenol ES – four daily.

Family and social history

The patient reported that he had been married for 8 years and that this was his second marriage. He reported that he was generally happy. He had two children. He worked in finance. There was no family headache history. His mother died secondary to lung cancer.

Psychological factors

There were depressive signs or symptoms.

Physical examination

Cranial nerve examination

Examining cranial nerves II through XII was within normal limits, with the exception of some hyperalgesia to pin prick in the left V1 and V2 distribution. This was present only during a pain attack.

Motor and sensory examination

Reflexes were 2 + and symmetrical. Coordination was normal. Romberg was negative.

Stomatognathic examination

Stomatognathic examination revealed an essentially normal functioning temporomandibular joint. There was no evidence of joint noise or joint tenderness, and the range of motion was normal.

Upper quarter and cervical spine examination

Upper quarter and cervical spine examination was within normal limits.

Myofascial examination

Myofascial examination revealed a tender area in the left anterior temporalis which, when palpated, partially replicated his pain.

Further work-up included complete blood count, erythrocyte sedimentation rate – all of which were within normal limits.

Case discussion

Although the patient presented with SUNCT symptoms, it was felt that a repeat indomethacin trial at doses up to 225 mg might be useful. There was no benefit. The patient was then treated, in October of 1996, with gabapentin at doses of 300 mg three times daily. The patient had a dramatic response to gabapentin and increased to doses of 600 mg three times daily, with the report that he was almost pain free.

At that time the patient was lost to follow-up, as he moved from the Los Angeles area. He returned to treatment in January of 1999, stating that since he discontinued the gabapentin in 1996 he had persistent SUNCT symptoms. Gabapentin was resumed and within several weeks, at doses of 900 mg three times daily, he reported being pain free. At the last follow-up in December 1999 he was still taking gabapentin and had no pain.

Conclusion

This SUNCT case seems to have had long-term response to gabapentin. The literature does not reveal any medication that consistently helped SUNCT. Although it has been suggested that other membrane stabilizing medications, such as carbamazepine and lamotragine (5), may be effective, they are inconsistent. This case presentation represents possible hope for patients with SUNCT. The fact that SUNCT seems to respond to drugs commonly used in neuropathic pain may suggest the mechanism requires at least a nociceptive component that is neurally mediated. There are striking similarities with SUNCT and trigeminal neuralgia (6). Further review of the associated autonomic features and their mechanism may shed light on the relationship. The prednisone response is also interesting, as it is reminiscent of the responses seen in cluster headache. However, the lack of response to verapamil perhaps suggests a neural process and less of a vascular mechanism.

Why this patient responded to gabapentin and others do not is puzzling. It is clear that there is a dose response that was initially at 1800 mg per day and now is at 2700 mg per day. If the dose is decreased below this the pain returns. It is therefore suggested that the dose be pushed to at least 3000 mg per day before declaring it a failure.

SUNCT may have spontaneous remission. This case is important in that the response to gabapentin occurred at two different time intervals 3 years apart. During the 3 years the patient was not taking gabapentin he was never in remission. He has tried to stop the gabapentin and each time the pain returns immediately.