Trigeminal Neuralgia Information - symptom, cause, treatment of Trigeminal Neuralgia
Trigeminal Neuralgia Information
Trigeminal neuralgia ("tic douloureux") is most common in middle and later life. It affects women more frequently than men.
Clinical Findings of Trigeminal Neuralgia
Symptoms of Trigeminal Neuralgia
Momentary episodes of sudden lancinating facial pain occur and commonly arise near one side of the mouth and shoot toward the ear, eye, or nostril on that side. The pain may be triggered or precipitated by such factors as touch, movement, drafts, and eating. Indeed, in order to lessen the likelihood of triggering further attacks, many patients try to hold the face still while talking. Spontaneous remissions for several months or longer may occur. As the disorder progresses, however, the episodes of pain become more frequent, remissions become shorter and less common, and a dull ache may persist between the episodes of stabbing pain. Symptoms remain confined to the distribution of the trigeminal nerve (usually the second or third division) on one side only.
Differential Diagnosis of Trigeminal Neuralgia
The characteristic features of the pain in trigeminal neuralgia usually distinguish it from other causes of facial pain. Neurologic examination shows no abnormality except in a few patients in whom trigeminal neuralgia is symptomatic of some underlying lesion, such as multiple sclerosis or a brain stem neoplasm, in which case the finding will depend on the nature and site of the lesion. Similarly, CT scans and radiologic contrast studies are normal in patients with classic trigeminal neuralgia.
In a young patient presenting with trigeminal neuralgia, multiple sclerosis must be suspected even if there are no other neurologic signs. In such circumstances, findings on evoked potential testing and examination of cerebrospinal fluid may be corroborative. When the facial pain is due to a posterior fossa tumor, CT scanning and MRI generally reveal the lesion.
Treatment of Trigeminal Neuralgia
The drug most helpful for treatment of trigeminal neuralgia is carbamazepine, given in a dose of up to 1200 mg/d, with monitoring by serial blood counts and liver function tests. If carbamazepine is ineffective or cannot be tolerated, phenytoin should be tried. (Doses and side effects of these drugs are shown in Table 24–3.) Baclofen (10–20 mg three or four times daily) may also be helpful, either alone or in combination with carbamazepine or phenytoin. Gabapentin, another anticonvulsant agent, may also relieve pain, especially in patients refractory to conventional medical therapy and those with multiple sclerosis. Depending on response and tolerance, up to 2400 mg/d is given in divided doses.
In the past, alcohol injection of the affected nerve, rhizotomy, or tractotomy was recommended if pharmacologic treatment was unsuccessful. More recently, however, posterior fossa exploration has frequently revealed some structural cause for the neuralgia (despite normal findings on CT scans, MRI, or arteriograms), such as an anomalous artery or vein impinging on the trigeminal nerve root. In such cases, simple decompression and separation of the anomalous vessel from the nerve root produce lasting relief of symptoms. In elderly patients with a limited life expectancy, radiofrequency rhizotomy is sometimes preferred because it is easy to perform, has few complications, and provides symptomatic relief for a period of time. Gamma radiosurgery to the trigeminal root is another noninvasive approach that appears to be successful in 80% of patients, with essentially no side effects other than facial paresthesias in a few instances. Surgical exploration generally reveals no abnormality and is inappropriate in patients with trigeminal neuralgia due to multiple sclerosis.