The trigeminal nerve provides sensory information to the brain about sensations like temperature and touch, says Devon Conway, MD, a neurologist at Cleveland Clinic Main Campus in Ohio. About 150,000 people a year are diagnosed with trigeminal neuralgia, according to the American Association of Neurological Surgeons. There are two kinds of trigeminal neuralgia, the most common being the typical or classic form, called TN1. “The nerve starts to dysfunction for one reason or another, and it can cause very severe pain — typically described as a kind of electric-shock sensation — that can last from a few seconds to a few minutes,” says Dr. Conway. In the “atypical” form, called TN2, the pain is more of a constant aching, burning, or stabbing pain that is somewhat less intense than in TN1, according to the Facial Pain Association.
What Are the Symptoms of Trigeminal Neuralgia?
The pain associated with trigeminal neuralgia is usually recurrent and happens on one side of the face, typically in areas of the face where the trigeminal nerve goes, says Conway. “There are three branches of the trigeminal nerve: One is mostly the forehead, one is between the chin and the forehead, and the other is from the chin down,” he says. “Basically, the patient will have this bad, shocking sensation, which is often triggered by something, though in some situations the pain could be almost continuous,” says Conway. It’s a very severe pain that can sometimes be disabling for patients because of its intensity, he adds.
Who Is at Risk for Trigeminal Neuralgia?
Theoretically, anyone could develop trigeminal neuralgia, says Conway. One of the most common causes of pain is when the trigeminal nerve is being pushed on by a blood vessel, he says. “It’s a very crowded area back around the brain stem, with a lot of blood vessels and exiting cranial nerves, including the trigeminal nerve,” he says. “If the vascular structure is pushing against the nerve it can cause this dysfunction and trigger the pain,” says Conway. In people with multiple sclerosis (MS), the pain can be a result of the underlying pathology of MS, called demyelination, where the insulation is removed from the wires of the nerves, says Conway. “When that occurs in the area where the trigeminal nerve is in the brain stem structure, known as the pons, then that can trigger pain,” he says. But some MS patients may seem to have both issues going on, where they have a vascular structure compressing the nerve and demyelination in the pons — it’s sort of like a double whammy, says Conway. “There are also cases of trigeminal neuralgia where we aren’t able to determine what the cause is,” he says. “It doesn’t mean that there isn’t one, it’s just that we haven’t developed the technology to detect it yet,” he adds. The risk of developing the disorder is higher for women and for people older than 50, though it can happen anytime, even in infancy, according to the National Institute of Neurological Disorders and Stroke. Approximately 2 to 5 percent of people with MS can develop it, says Conway.
How Is Pain Triggered in Trigeminal Neuralgia?
Classically, the pain is triggered by something, says Conway. Activities like chewing certain foods or environmental conditions like wind blowing against the face can bring on a painful episode, he says. “Chewing anything can bring the pain about, but sometimes the pain is triggered by certain foods; nuts are a common example,” says Conway. Triggering foods can also include ones that bring on heat, like salsa, or cold, like mint. Sweet and sour can bring on an episode, as well; the sharper the taste sensation, the more likely the food is to activate signals that can set off the pain, according to the Facial Pain Association. “Sometimes we have to hospitalize people because they’re not able to get adequate nutrition because of the pain of chewing,” says Conway. RELATED: How MS Can Affect Your Oral Health
How Does Having Trigeminal Neuralgia Impact Everyday Life?
Trigeminal neuralgia impacts all aspects of life, and anything a person might want to do, says Conway. “For instance, maintaining employment is challenging for a person who has MS and trigeminal neuralgia. If that person is constantly in pain, they often have difficulty concentrating,” he says. Leisure activities and relationships can also be less enjoyable because of the pain, so it’s very limiting in that respect, says Conway. Research suggests that people diagnosed with trigeminal neuralgia are at higher risk for developing depression, anxiety, and sleep disorders.
How Is Trigeminal Neuralgia Diagnosed?
The diagnosis for trigeminal neuralgia is clinical, meaning that it’s based on symptoms, patient history, and a physical exam rather than something like a blood test, says Conway. “Any patient who is reporting what I described — intermittent, shocking, stabbing pain, especially limited to one side of the face and limited to one of the branches of the trigeminal nerve — those would all be strong clues pointing towards a diagnosis of TN,” he says. “If we are suspicious of a vascular structure [as the cause], getting an MRI might be helpful, because it can enable us to see if a blood vessel is compressing the trigeminal nerve or see if the nerve looks somewhat deformed,” says Conway. “The MRI would also help if the patient has MS so that we could look for evidence that the multiple sclerosis is affecting the area around the trigeminal nerve,” he says.
How Is Trigeminal Neuralgia Treated?
There are a number of drugs that have been shown to have benefits in treating trigeminal neuralgia, says Conway. Known as anticonvulsant medicines, the drugs block nerve firing and include Tegretol (carbamazepine), Trileptal (oxcarbazepine), Neurontin (gabapentin), and Lamictal (lamotrigine). There’s also a medication called baclofen, which is a muscle relaxer, says Conway. “Typically, we would start with one of these treatments, or sometimes we might even use combination therapy in the hopes of getting the patients’ symptoms under control; this works in many cases,” says Conway. If medication isn’t successful, there are surgical treatment options, including rhizotomy and surgical microdecompression.
Rhizotomy
In this kind of surgery, we are trying to “lesion” the nerve, which means to damage it so that it’s no longer transmitting those pain signals, says Conway. There are different ways to perform rhizotomy, which typically offers pain relief for one to three years:
Balloon decompression injures the insulation on the nerves that are connected with the sensation of light touch on the face, according to the National Institute of Neurological Disorders and Stroke (NINDS).Glycerol injection is performed with a thin needle. The glycerol solution “bathes” the ganglion and damages the insulation of the trigeminal nerve fibers.Radiofrequency thermal lesioning (also known as RF ablation) uses small electric currents that pass through a needle to injure the nerve fibers.Stereotactic radiosurgery is also known as gamma knife or cyber knife. This technique uses computer imaging to focus beams of radiation where the trigeminal nerve exits the brain stem. This creates a lesion on the nerve that interrupts the transmission of sensory signals to the brain.
Unfortunately, any of these procedures can leave recipients with numbness in their face, because the main function of the trigeminal nerve is to supply the brain with that sensory information, says Conway. But “for many patients, if it relieves the pain, then it’s worth it,” he adds.
Surgical Microdecompression
In this procedure, the neurosurgeon tries to move the vascular structures so that they’re not compressing the nerves. This surgery is the most invasive, but offers the lowest chance of the pain returning, says the NINDS. It’s unclear how successful any of these surgical treatments are for treating trigeminal neuralgia in people with MS; more research needs to be done in this area, says Conway.
