Multiple Sclerosis and Trigeminal Neuralgia

Multiple sclerosis (MS) is a “so-called” demyelinating disease.  Myelin is the substance which surrounds nerve fibers and enables them to conduct fast electrical impulses.  In MS, the body’s immune system attacks the myelin leading to spots (called plaques) that are bare of myelin.  This leads to a variety of neurological symptoms, including loss of vision, loss of sensations, and loss of motor function, amongst others.  Sometimes these symptoms are temporary and sometimes permanent.  The treatment of MS is medical.  In the past five years a number of new drugs have been approved for treatment.

Trigeminal neuralgia may also occur, as a result of demyelination, in MS patients.  The symptoms are identical to TN in patients without MS.  But, again, the cause is different. Usually, in “regular” TN, we find an artery or a vein compressing the trigeminal nerve.  Moving that vessel usually relieves the pain, hence the “microvascular decompression procedure.”  In MS, microvascular decompression is much less likely to work because its a plaque in the brainstem, not a vessel, which is causing the pain.  Another unusual thing about MS trigeminal neuralgia is that it is frequently bilateral.

The treatment of choice for MS patients with trigeminal neuralgia is, therefore, the radio frequency lesion procedure (RFL).  This outpatient procedure takes about 10 minutes.  During brief anesthesia, a needle is inserted into the trigeminal nerve and the nerve cells are burned.  This leads to numbness in the region where the pain was previously present, but the pain is gone.  The procedure can be performed on both sides of the face, but care must be taken not to create bilateral jaw weakness or tongue numbness.