Trigeminal Neuralgia

TRIGEMINAL NEURALGIA • Trigeminal neuralgia (tie douloureux) is a facialpain syndrome of unknown cause that develops in middle to late life. More than 40 years old.

• Etiology: • In many instances, the trigeminal nerve roots are close to some vascular structure, and microvascular compression of the nerve is believed to cause the disorder.

• Symptom: • Pain is confined mainly to the area supplied by the second and third divisions of the trigeminal nerve (Figure 3--8). Involvement of the first division or bilateral disease occurs in less than 5% of cases. Characteristically, lightninglike momentary jabs of excruciating pain occur and spontaneously abate. Occurrence during sleep is rare.

• Painfree intervals may last for minutes to weeks, but long-term spontaneous remission is rare. Sensory stimulation of trigger zones about the cheek, nose, or mouth by touch, cold, wind, talking, or chewing can precipitate the pain. Physical examination discloses no abnormalities.

• Rarely, similar pain may occur in multiple sclerosis or brain stem tumors, and these possibilities should thus be considered in young patients and in all patients who show neurologic abnormalities on examination.

• Auxiliary Examination: • In idiopathic cases, CT scan and MRI fail to show any abnormality, and arteriography is similarly normal. Any vascular structure compressing the nerve roots is generally too small to be seen by these means.

• Diagnosis and Differential Diagnosis: • according to the charcterstic symptom of • facial pain in the area of three divisions of trigeminal nerve. lightninglike momentary jabs of excruciating pain occur and spontaneously abate.We can make a diagnosis, but we must take differential diagnosis from toothache.

• The characterstic symptom of toothache: not lightninglike momentary jabs of excruciating pain occur and spontaneously abate. the pain always last several hours and gradually reduction and disappear completely after taken a proper treatment by dentist.

• Treatment : • Remission of symptoms with carbamazepine,400--1200 mg/d orally in three divided doses, occurs within 24 hours in such a high percentage of cases that some believe it to be diagnostic. Rarely, blood dyscrasia occurs as an adverse reaction to carbamazepine.

• Intravenous administration of phenytoin,250 mg, will abort an acute attack, and phenytoin,200--400 mg/d orally, may be effective in combination with carbamazepine if a second drug is necessary. Lamotrigine 400 mg/d or baclofen 10 mg three times daily--20 mg four times daily has been used in refractory cases. Posterior fossa microvascular decompressive surgery has been used in drug-resistant cases.