Abstract
Case report
A 40-year-old single man presented with a 17-year history of continuous (present all the time), strictly left-sided headache. The pain was non-pulsatile (pressing quality), with moderate intensity and maximally felt in the frontotemporal area. There were periods of pain exacerbations during which bilateral conjunctival hyperaemia, mild unilateral ptosis and vomiting could be noticed. Precipitation factors were denied. Both general physical and neurological examinations were normal. The patient underwent extensive investigation including cerebrospinal fluid examination, brain magnetic resonance imaging, cerebral angiography and magnetic resonance angiography. No abnormalities were detected. Non-steroidal anti-inflammatory drugs, corticosteroids, benzodiazepines, tricyclic antidepressants, lamotrigine, barbiturics, ergotamine and dihydroergotamine, opiates, zolmitriptan and sumatriptan had no effect at all. The patient was then admitted to an inpatient unit. During the hospitalization period, indomethacin was prescribed in doses up to 200 mg a day, for 7 days; no improvement was observed. Then the patient was prescribed chlorpromazine 50 mg a day, prometazine 50 mg a day and dexamethazone 13 mg a day; at day four a mild improvement could be seen. Great occipital nerve block was performed but no improvement was obtained. One day after starting gabapentin, 1200 mg a day, there was complete pain relief, which remained during the 6-month follow-up period.
Discussion
‘Hemicrania continua’ (HC), first described by Sjaastad & Speriengs in 1984 (1), is characterized by a strictly unilateral continuous headache of moderate severity associated with autonomic disturbances. The complete response to an adequate dose of indomethacin is so far regarded as sine qua non for diagnosis (1–4). It is a strictly unilateral headache, although a bilateral case has been reported (2, 4). Its intensity is usually described as moderate or severe, but an excruciating intensity as seen in cluster headache is not usual. There are no trigger zones. During exacerbation periods, the pain may be associated with autonomic disturbances such as miosis, ptosis, conjunctival injection, nasal congestion and tearing (5). Some other accompanying symptoms, like nausea, photophobia, phonophobia, vomiting and ocular discomfort have already been reported (2).
HC is regarded as a primary headache; however, there is a report of a case possibly secondary to skull-based tumour (6), another report of two cases presumably caused by cervical disc disease (7, 8) and another one related to analgesic rebound (9). Sjaastad & Antonaci (10) proposed two clinical patterns of HC: the unremitting and the remitting forms. The unremitting form has two subtypes: unremitting from onset (our patient could be included in this subtype) and unremitting evolved from remitting. The majority of the patients studied by Newman et al. (4) had the unremitting form (53% had the unremitting from onset subtype and 32% were classified as the unremitting evolved from remitting subtype).
The striking indomethacin effect on this particular headache is an intriguing matter. Indomethacin is a potent inhibitor of cyclooxygenase activity, like other anti-inflammatory drugs, indeed, there are reports of partial response to naproxen (2, 4) and to ibuprofen (4, 11), and also there are reports of an absolute response to piroxican (12) and rofecoxib (13).
Feigen et al. (14) showed the occurrence of a vascular action of indomethacin in dogs and Quintana et al. (15) suggested that indomethacin might affect the cerebral circulation without involving cyclooxygenase inhibition.
Even though an absolute response to indomethacin is regarded as sine qua non for the HC diagnosis, Kuritzky (16) described two cases of ‘indomethacin-resistant hemicrania continua’: a 35-year-old man who did not respond to indomethacin up to 100 mg per day and a 33-year-old woman who had ‘a very small reduction in the severity of attacks’ during treatment with 75 and 100 mg per day of indomethacin. As observed by Newman et al. (4), those patients were given a suboptimal dose (none of them was given doses higher than 100 mg daily). Our patient, however, took indomethacin up to 200 mg a day for 1 week without any benefit. On the other hand, the response to gabapentin 1200 mg daily was dramatic. The patient has been on the drug for 6 months. No tachyphylaxis was observed.
Gabapentin has been used for the treatment of several paroxysmal and neuropathic conditions, such as trigeminal neuralgia, migraine, reflex sympathetic dystrophy (17), post-herpetic neuralgia (18) and anaesthesia dolorosa (19), in SUNCT syndrome (20) and in chronic cluster headache (21).
Our patient had a pain similar to hemicrania continua, but it was refractory to indomethacin and responsive to gabapentin. Cases like ours lead us to favour a more inclusive set of criteria, as proposed by Silberstein et al. (22). The headache must have either one of:
Complete response to indomethacin.
One of the following autonomic features in association with exacerbation of pain: lacrimation, nasal congestion, rhinorrhoea, ptosis and eyelid oedema.
Otherwise, the response to indomethacin is so dramatic and selective that this drug is probably counteracting essential pathophysiological mechanisms of such a disorder. Therefore, the described headache may not be a hemicrania continua. It could be either a variant of hemicrania continua or a completely different headache. The description of another cases is necessary to answer these questions.