Trigeminal neuralgia is intensely severe facial pain, which shoots across the face, lasting minutes to hours. This pain can involve any of the three sections of the trigeminal nerve, including the branches, which innervate the forehead and eye, the cheek, or the jaw. Trigeminal neuralgia is caused by compression of the trigeminal nerve by blood vessels.
Trigeminal neuralgia is not life-threatening, but the pain — variously described as burning, stabbing, or like an electric shock — can be severe enough to cause physical and emotional distress.
Typically, when the condition first develops the pain comes and goes, with painful episodes lasting only a few seconds and with long intervals between attacks. As the condition progresses the pain becomes constant or the interval between episodes becomes shorter — sometimes only a few minutes. Sleep provides respite, but symptoms resume upon awakening.
The source of the pain is the trigeminal nerve, also known as the fifth cranial nerve, or CNV. The trigeminal nerve transmits signals between the brain and the face, eyes, and teeth as well as the muscles that control chewing. (If you’ve ever experienced a “brain freeze” from slurping a milk shake or a frozen drink, you’ve met your trigeminal nerve.) There are two trigeminal nerves, one on each side of the face, and each has three branches: the ophthalmic nerve, the maxillary nerve, and the mandibular nerve. Trigeminal neuralgia can affect any of these three, but is most commonly a condition of the maxillary and mandibular nerves.
Episodes of trigeminal neuralgia may be spontaneous, or they may be triggered by mild stimulation of the face (such as shaving, applying makeup, chewing, washing, and even exposure to wind). Over time, the attacks can grow in duration, intensity, and frequency.
Diagnosis and Treatment
Trigeminal neuralgia is generally diagnosed with a combination of physical examination and evaluation of symptoms, but it’s a diagnosis by exclusion — if a patient (especially a woman over 50) complains of the classic symptoms of trigeminal neuralgia and other possible conditions can be ruled out, a doctor will probably diagnose TN and refer the patient to a neurologist, neurosurgeon, or pain management specialist. A patient under 40 with the same symptoms may be tested for multiple sclerosis.
In most cases, a neurological exam is normal except for the patient’s history of facial pain. In some cases, the doctor will order blood work to rule out conditions such as lupus or scleroderma, or a CT or MRI scan to look for a tumor or arteriovenous malformation (AVM). These scans may reveal abnormal or elongated blood vessels that provide clues to the source of the pain. For the most part, however, trigeminal neuralgia can be diagnosed on the basis of the symptoms alone.
Since the goal is pain relief, TN treatment usually begins with medications known to be effective against nerve pain, including anti-spasmodic, anti-epileptic (anticonvulsant), and tricyclic anti-depressant drugs, since these quiet down hyperactive nerves and dull pain signals from the trigeminal nerve. Carbamazepine is the first line drug used by many physicians to treat trigeminal neuralgia. Failure to obtain relief of pain often prompts the physician to search for other causes than trigeminal neuralgia. The effects of carbamazepine are known to decrease over time. Baclofen is a muscle relaxant which is often more effective when used with an anticonvulsant such as carbamazepine or phenytoin. Oxcarbazepine is a newer medication that is related to carbamazepine, with fewer side effects. Furthermore, medications such as gabapentin/pregabalin or Tricyclic anti-depressants (amitriptyline/nortriptyline) can be used.
Patients sometimes try complementary and alternative medicine (CAM) approaches, either alone or in conjunction with prescription medications. CAM treatments include acupuncture, acupressure, vitamin therapy, and electrical stimulation of the nerves.
When medical therapy loses effectiveness over time, there are several minimally invasive percutaneous approaches for treatment. These can include vascular decompression, radiofrequency which involves destruction of part of the nerve, or neuromodulation suppressing the pain signal to the skin.