Abstract
Introduction
Trigeminal neuralgia has been described in patients with other concomitant headache disorders. Striking examples are the so-called ‘Cluster–Tic Syndrome’ (1, 2) and Chronic Paroxysmal Hemicrania–Tic Syndrome (3). This report documents a previously undescribed paired association in a patient with migraine who described consistent recurring trigeminal neuralgia symptoms at the time of her migraines, with excellent response to gabapentin.
Case report
A 44-year-old-woman was seen in a headache centre at a tertiary care medical centre on referral from her neurologist. She had had viral meningitis nine years previously, which left her with anosmia (which eventually resolved), and occasional, brief (1–2 s duration) lancinating pains in the area of her right cheek. On some occasions, she noted involvement of the left cheek instead. There was also an ill-defined, milder aching component of pain, which was intermittent as well. There were no trigger maneuvers which brought on pain.
Over the previous several months, she began to experience a change in the pattern of pain. She now described stereotyped episodes, approximately three times monthly, of left lancinating maxillary region pain with radiation to the left pre-auricular area, upper gum and temporal regions. The onset of this pain was invariably followed within several hours by a throbbing left hemicrainial headache accompanied by photophobia, phonophobia, nausea and vomiting. Over the preceding months, she had also begun to experience visual symptoms during the early phases of headache, including photopsias and scintillations. She also described difficulty with speech production, and occasionally mild numbness in the right hemibody (arm, trunk and leg), neither lasting more than several minutes. She denied lacrimmation and nasal congestion accompanying headaches. Rarely, headaches occurred without preceding lancinating facial pain. Headaches had led her to use excessive amounts of an acetaminophen-aspirin-caffeine preparation on many days, even when pain was at a minimum, for fear of developing the full syndrome of pain. She denied any prior history of headaches, and denied having a history of seizures, stroke or head trauma. There was no family history of headaches.
Medical history was remarkable only for sinus disease, which led to surgery nine months previously (which did not help headaches, or change any of her symptoms). She took a thyroid replacement medication for hypothyroidism, which is of unknown aetiology. She had never been pregnant. Menstrual periods had been irregular for some time (months to years). She typically had one cup of coffee daily, did not smoke, and drank no alcohol. She exercised regularly.
Examination revealed a mildly obese woman with normal vital signs including blood pressure of 122/78, and regular pulse of 62. Neck was supple. There were no carotid bruits. There was no spinal tenderness and no tenderness in the face or head. Funduscopic exam was normal. Lungs were clear and cardiac auscultation was normal. Mental status exam was normal, with no language or other cognitive difficulties. Cranial nerve exam was normal. Specifically, smell was grossly intact, corneal reflexes were normal, facial sensation and movement were intact, and hearing was normal. Motor tone and strength were excellent. Sensation was normal. Muscle stretch reflexes were normal. Coordination and gait were normal.
MRI of the brain performed 8 years previously was normal, as was a recent EEG. Complete blood count, electrolytes, glucose and thyroid function testing were normal. Repeat MRI scan with and without gadolinium was arranged, and was found to be normal except for a midline frontal sinus retention cyst.
The patient was instructed to discontinue all previous analgesic medications and start gabapentin at a dose of 100 mg twice daily, to be increased in a stepwise fashion over the next several weeks. At 200 mg three times daily, lancinating pain disappeared, and headaches, as well as her accompanying symptoms, became milder and infrequent (less than once per month). She found that rizatriptan, 10 mg orally, successfully aborted virtually all headaches that did occur.
Discussion
This case seemingly exemplifies the coexistence of two distinct pain conditions: intermittent migraine (at times with aura), and trigeminal neuralgia. Migraine is common, and trigeminal neuralgia, while relatively uncommon, is by no means rare, so the coexistence of these two conditions is perhaps coincidental. However, the timing of symptoms in this patient suggests a pathophysiological link. Diagnostic evaluation excluded the presence of a mass lesion, arteriovenous malformation, or other intracranial/pericranial lesion to explain both pain morphologies. The simultaneous eradication of both types of head pain with gabapentin prophylaxis also tends to imply a shared or linked mechanism.
Migraine is considered by many authors to be generated by activation of a pathway involving trigeminal nerve sensitization as well as trigeminal-mediated neurogenic inflammation of meningeal arteries, via antidromic release of inflammatory neuropeptides in their perivascular spaces. This trigeminovascular theory is supported by a number of observations (4).
The pathophysiology of trigeminal neuralgia has been controversial, but clearly some change in sensitization, either peripherally, or in the trigeminal nerve's central projection pathways, must be involved in some fashion. One of the most popular theories is that the trigeminal nerve, at least in many affected patients, is altered by physical compression by one or more vascular structures near its emergence from the pontomedullary axis (5).
A potential overlap in the mechanisms of migraine and trigeminal neuralgia is apparent in the postulated involvement of the trigeminal system in both entities. We surmise that in the patient described here, a neuropathic pain mechanism is present with the interesting juxtaposition of both neuralgiform pain (the brief lancinations), and migrainous headache. The occurrence of visual and other aura symptoms preceding the headache is quite interesting in this case, since aura phenomena have not been linked to trigeminal activation.
Neither cluster headache nor Chronic Paroxysmal Hemicrania (CPH) features were noted in our patient, thus ‘Cluster–Tic Syndrome’ and ‘Chronic Paroxysmal Hemicrania–Tic Syndrome’ are not really diagnostic possibilities. Both the stereotypic visual auras (as well as occasional dysphasia and hemisensory deficits), and response to the relatively specific antimigraine agent rizatriptan we feel tend to confirm the presence of migraine.
Conclusion
A novel syndrome, ‘Tic-Migraine’ seems to be present in the patient described. Based on the apparent link between the two types of pain described by this patient, the hypothesized causal trigeminal nerve involvement in migraine is further supported. This patient's excellent response to gabapentin supports other authors’ reports of its usefulness in neuropathic pain and migraine, and should certainly be considered in other cases of migraine with associated lancinating pain.