The interval between attacks can range from minutes to months or even years, and pain is completely absent during these times. Recurrences of the pain are almost always in the same area of the face, but tend to spread. The trigeminal nerve is the fifth and largest of the brain's twelve nerves, carrying both motor and sensory messages from the face to the brain. However, the current theory is that disease or irritation of the nerve increases the firing of sensory impulses, so much so that trigger points for pain develop on the face and in the mouth as a result of this overload. Trigeminal neuralgia also can be activated by such conditions as multiple sclerosis, tumors and abnormal blood vessels.
Stress is less often a contributing factor.
A diagnosis is made by considering the patient's medical history and description of his or her pain. While no specific diagnostic tests are available to confirm the presence of trigeminal neuralgia, diagnostic-imaging technologies, including CT scans and MRIs, are often used to assess the patient and make sure that a tumor or other abnormality is not causing the pain. In most cases, treatment for trigeminal neuralgia begins with anticonvulsant drug therapy that seeks to suppress the transmission of impulses by the trigeminal nerve. Carbamazepine is the first drug of choice. It should be started at low doses and titrated, and taken with food or fluid.