Of all of the symptoms of MS, few make patients as miserable as a syndrome known as trigeminal neuralgia (TN). The trigeminal nerve is the nerve that carries sensation from the face to the brain, and also carries motor fibers for the muscles used in chewing. TN is a facial pain-syndrome in which patients experience a brief, severe, shock-like pain, usually over the cheek and the jaw, though it can occur over the forehead as well. The pain lasts from several seconds to minutes and patients can experience multiple attacks throughout the day. It is also known as tic douloureux as patients “tic” in pain when they experience an attack. Although most patients with TN do not have MS, when MS is the cause, it is due to a demyelinating plaque where the trigeminal nerve enters the brain. An MRI showing this is below, though the lesion may be too small to be detected on MRI.
Attacks of TN can be triggered by mild stimuli, like brushing ones teeth or chewing food. Patients with TN routinely tell me that they are able to chew their food on only one side of their mouth, and I met one poor patient who had to have a feeding tube placed because she could not chew her food at all. TN is also known as the “suicide pain” due to its severity and the negative impact it has on patients’ lives. A key feature of the diagnosis of TN is that objective sensory loss is not found on examination. TN is often mistaken initially for dental disease, and it is not unusual to meet patients who have lost several teeth as a result.
The initial treatment of choice is with carbemazepine (Tegretol). This is an older anti-seizure medication, which is effective in 50-75% of patients. Other antiepileptic medications (oxcarbazepine, phenytoin, neurontin), as well as clonazepam and baclofen are often used as well. These medications are usually quite safe, though they can cause sedation and dizziness.
In some patients, TN may be caused by an aberrant vessel contacting the trigeminal nerve root and ultimately interventional procedures may be required if the pain is not controlled by medications alone. Radiation or chemical injections can be made directly to the nerve. These procedures usually provide short-term relief to nearly all patients, though they are not a definitive treatment and the pain may return.