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mise à jour du
14 février 2002
Neurology
2000;54:1368-70
 
Glossopharyngeal neuralgia and MS
Alireza Minagar, William A. Sheremata
University of Miami, School of medecine, Florida, USA
Headphone neuralgia A Skelton
Primary yawning headache DE Jacome

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Weisenberg first described glossopharyngeal neuralgia (GPN) in 1910, but it was Harris in1921, who reported the first idiopathic case and coined the term "glossopharyngeal neuralgia" . The syndrome is manifested by paroxysms of excruciating pain in the posterior pharynx, tonsillar fossa, and base of the tongue, often radiating to the external auditory canal or the neck. The pathogenesis of GPN is unknown but probably involves both central and peripheral mechanisms. Pain is in the distribution of the glossopharyngeal nerve but may include the territory of the auricular and pharyngeal branches of the vagus nerve. Chewing, talking, swallowing, or yawning triggers pain. The clinical manifestations of GPN resemble trigeminal neuralgia (TN). We report four MS patients with GPN, three of whom were treated with carbamazepine.

Patient 1. A 43 year-old Hispanic-American woman was diagnosed with MS in 1990. She remained stable until May 1995 when she experienced two generalized tonic-clonic seizures. Shortly thereafter she experienced severe knifelike pain radiating into her right ear. The pain was always unilateral, lasting a few seconds. Painful paroxysms occurred frequently and were triggered by chewing and swallowing. Seizure control was attempted with phenytoin but failed. Carbamazepine was initiated with escalation of the dose to 1g daily with subsequent control of seizures. At this dose of carbaniazepine, relief of pharyngeal pain occurred.

Patient 2. A 63-year-old man with a 27 year history of relapsing-remitting MS was stable when in 1985 he experienced onset of paroxysinal lancinating pain involving his left ear, base of the tongue, and tonsillar fossa. Each paroxysm lasted a few seconds and was triered by chewing and yawning. Two neurosurgeons and in oral maxillofacial surgeon concurred with the diagnosis of GPN. Treatment with carbamazepine 600 mg daily resulted in pain relief after 4 weeks. One attempt to Withdraw carbaniazepine caused recurrence of pain, which responded to reinstitution of the drug.

Patient 3. A 54-year-old man with a 35-year history of MS presented in February 1998 complaining of recurrent attacks of severe, sharp pain localized to the posterior pharynx, tonsillar region, and base of the tongue. Pain radiated to the left ear and was precipitated by chewing and swallowing. No hearing loss, tinnitus, or vertigo was present. An otolaryngologist concurred with a diagnosis of GPN. He had a prompt salutary response to carbamazepine at a dosage of 300 mg daily.

Patient 4. A 22-year-old woman with rapidly progressive MS was admitted to the hospital because of new-onset nausea, vomiting, and severe ataxia. Four years earlier she had experienced numbness of her lower extremities accompanied by dizziness. A few months later she developed right-side optic neuritis and weakness of her left hand, and was diagnosed with MS. During the next 2 years she had multiple relapses with limited responses to IV methylprednisolone or adrenocorticotrophin hormone (ACTH). In Januarv 1999 she had severe, sharp pain involving her left ear more than throat and tonsillar fossa, occurring several times daily. Each painful episode was triggered by chewing and lasted for less than a minute. The patient declined treatment with carbamazepine but pain abated after 10 days of 1 mg IV synthetic ACTH and 8 mg/kg cyclophosph mide treatment daily.

Results. Of a population of 8000 patients seen at the MS Center, University of Miami during a 20-year period, we identified four patients (two men and two women) with GPN: an incidence of 0.5:1000 MS patients. The average age of the patients was 47 years (range, 21 to 35 years) and the duration of MS ranged from 4 to 36 years. Onset of GPN in our MS patients was manifested by the sudden onset of unilateral sharp, lancinating pain in the ear, base of the tongue, and tonsillar fossa. Patients reported that the duration ofthe painful paroxysms usually lasted a second or less but could last to a few seconds. Occasionally pain was described by patients as lasting a "few minutes." Duration of pain witnessed in the clinic was always very brief, but the pain could appear repeatedly. Anticipation of the pain caused great anxiety in the MS patient who reported longer duration of pain. Pain-free intervals lasted hours to days. In our serics, GPN was not associated with bradycardia, or hypotension, as has been reported. In no instance was GPN the initial manifestation of MS.

All patients underwent brain MRI during and after the development of GPN. Brain MRI did not reveal any pathology in the medulla nor involvement or compression ofthe glossopharyngeal nerve by neoplasms, infection, or anomalous blood vessels.

Three patients were treated with carbamazepine with complete relief of pain. A fourth patient declined carbamazepine but pain resolved gradually during ACTH and cylophosphamide administration. In the last 9 months this patient has remained pain free. Carbamazepine withdrawal in one male patient was associated with relapse of GPN within 1 week, but reintroduction of carbamazepine relieved the pain. The average follow-up of three patients on carbamazepine was 6 years (range, 1.5 to 14 vears), during which they tolerated the medication well.

Discussion. GPN may, uncommonly, complicate MS, as illustrated in our patients. GPN has been attributed to vascular compression of the nerve root entry zone, resulting in demyelination and ephaptic transmission. This hypothesis has served as a rationale for microvascular surgical decompression. Alternatively, vascular compression of a nerve has been hypothesized to induce repetitive activation of primary afferents in the nerve and has led to hyperactivity and hyperexcitability in the central neurons. Activation of N-methyl-D-aspartic acid receptor has been invoked as another possible explanation. However, in MS patients, other potential causes should be considered. Oppenhelm has described demyelinating plaques at the root entry zone as the potential cause of paroxysmal TN in MS patients. It is likely that similar root entry zone lesions of the glossopharyngeal nerve are associated with ephaptic conduction and underlie the pathogenesis of GPN.

Atypical facial pain may mimie some of the clinical features of both TN and GPN. Atypical facial pain is eliminated from the differential diagnosis by the brevity of the recurrent severe pain experienced by our patients as well as the precise localization of their pain. Atypical facial pain is usually persistent, deep, and aching, and is often bilateral. Although sometimes more severe, the pain lacks the typical sharp lancinating character oft he paroxysms seen in our patients with GPN.

The incidence of GPN in our patient population (0.5:1,000) is in contrast to that of TN, which has an incidence of 40:1000 (4%) MS patients. Although the numbers reveal the rarity of GPN in the MS population, our observations reveal approximately the same ratio of TN to GPN in the general population. In the general population. incidence of GPN is 0.2 to 1.31% of that of TN. The population-based study of GPN in Rochester, MN, revealed peak incidence rates in the sixth through eighth decades. This observation shows that GPN, although less frequent than TN, may occur at a younger age and early in the course of MS suggests that similar mechanisms may be operative. Anecdotal reports on treatment of GPN in patients without MS suggest benefit may be obtained from the use of carbamazepine, phénytoin or baclofen indoses similar to those used to treat TN. In our series GPN was responsive to carbamazepine and identification of MS patients with GPN is warranted.