By: Ellen Whipple Guthrie, Pharm. D.
Individuals with MS tend to experience a variety of symptoms that can interfere with activities of daily living and decrease their quality of life. We will examine two common symptomatic problems, numbness and weakness, and explore their various treatment options.
One of the most common symptoms experienced by those with MS, numbness occurs when the nerves that transmit sensations do not conduct information properly. As a result, sensations in that particular area are either lacking or nonexistent. Numbness is often one of the first symptoms experienced by people diagnosed with MS and can affect a very small area (such as a spot on the face), or it can affect entire areas of the body (such as feet, arms, and legs). In most instances, numbness only lasts for a short period of time and goes away on its own. For this reason, many consider numbness to be more of an annoyance than a disabling symptom. However, in severe cases, numbness can interfere with a person’s ability to function normally. Numbness of the legs that limits mobility is an example of numbness that can negatively affect a person’s activities of daily living.
Although numbness is sometimes a harmless symptom, those who experience numbness should still exercise caution. Individuals with MS who have severe facial numbness should be careful when eating or chewing food in order to avoid biting their mouths and/or tongues. Likewise, they should make sure that their food (or drink) is not too hot, to avoid burning their mouths. In addition, those who experience numbness of their extremities (arms and legs) should be especially careful around open flames, hot water, and other sources of heat in order to prevent being burned.
Focusing on numbness generally makes the problem worse. The best approach is to realize that this type of sensory symptom does not usually last long and will most likely remit on its own. When numbness affects activities of daily living or is extremely bothersome, a short course of intravenous corticosteroids may be necessary. Some people may also be helped by as-needed doses of gabapentin (Neurontin®), pregabalin (Lyrica®), or amitriptyline.
Weakness is experienced by over half of people who have MS. There are two fundamental causes of weakness in individuals with MS. First, weakness can be caused by spasms and fatigue. This type of weakness presents as loss of strength and control in the extremities. Second, weakness can result from damaged nerves, which prevent signals from reaching the extremities. This type of weakness does not result from diminished muscle strength. It is vital that the source of the weakness be understood in order to properly treat it.
Weakness due to spasms and fatigue generally responds best to exercise regimens designed by a therapist. Not surprisingly, this type of weakness can also be significantly improved by treating the underlying causes of the weakness — spasticity and fatigue. Antispasm medications make muscles less stiff, and this can decrease weakness. Likewise, anti-fatigue medications decrease fatigue and may in turn, increase strength.
However, weakness may be the result of poor electrical conduction across nerve fibers where myelin has been damaged. This may be temporary, as a result of an increase in symptoms with prolonged exertion or heat exposure. Overall, the benefits of exercise for a person with MS outweigh the risk of these symptoms. Ways of managing these symptoms include cooling vests and a class of drugs called aminopyridines. These drugs are not yet FDA-approved but can be prescribed by a physician and prepared by a compounding pharmacist. One of these drugs, Fampridine SR, is currently being tested in clinical trials.
It is important to note that while treatment with the disease-modifying drugs (Avonex®, Betaseron®, Copaxone®, Rebif®, Tysabri® and Novantrone®) does not reduce symptoms like numbness and weakness that are already present, their use may reduce the likelihood of new symptoms. While these medications are not a cure for MS, recent studies have demonstrated that early initiation of treatment may reduce short-term and potentially long-term neurological impairment. The consistent use of these medications may lessen many of the symptomatic problems caused by MS.
Ellen Guthrie practices pharmacy at Children’s Healthcare of Atlanta where she is a pediatric pharmacist. She is also a freelance medical writer and peer reviewer with the American Pharmacists Association and the Consortium of MS Centers. She has been a medical advisor to the MSF since 2002.
(Last reviewed 10/2009)