In the past, many scientists and health care workers considered MS to be a “painless” disease but many people living with MS, might disagree with this strongly.
While reported rates of MS-related pain have been as low as 28% and as high as 90 %, Generally it is agreed that the figure lies anywhere from 43-80% of people with MS. This variability may be explained by the fact that different studies use different sources for obtaining participants (for example, hospital inpatients versus outpatients) and different methods for selecting which participants will be surveyed. According to at least one US study and several European studies, pain problems may occur more frequently and with greater severity in people living with MS relative to the general population. So we can probably say that half of all people with MS will experience pain from time to time because of the condition. For a small number, pain is a severe and ongoing symptom that may need specialised assessment and management but fortunately for most, the pain is usually mild. It cannot be predicted by a person’s age, gender, or type of MS. But the longer someone has had MS, the more likely they are to experience pain as one of their symptoms.
Pain is defined as an “unpleasant sensory experience associated with actual or potential tissue damage or described in terms of such damage”. In MS, symptom management is the primary focus for medical workers.
Neurogenic pain is typically initiated by a lesion or dysfunction in the peripheral or central nervous system, which has no “biological advantage” but causes suffering and distress. Clinical hallmarks are a burning, piercing pain,
o Allodynia (a painful response to nonpainful stimuli), and/or
o Hyperalgesia (an increased response to painful stimuli).
In MS, some types of pain can be experienced over a long period of time or can be intense but brief. Many people living with MS experience both.
Neurogenic pain, common in MS, includes dysaesthetic pain and it is this that this article addresses.
A number of studies have reported dysaesthetic pain to be among the most common pain syndromes associated with MS. It is described as a constant symmetric or asymmetric burning, tingling, tightness, or aching sensation, usually affecting a person’s lower limbs, more frequently distally (i.e. farther away from the body, such as in the feet and lower legs). A degree of sensory loss associated with dysaesthetic pain can be identified during a neurological examination. This dysaesthetic pain may be worse at night and after exercise but it may also be aggravated by increased temperature and humidity.
First-line medications for the treatment of dysaesthetic pain in MS are tricyclic antidepressants, including amitriptyline, nortriptyline and clomipramine. Anticonvulsant medications such as carbamazepine, lamotrigine and gabapentin are also used in treating dysaesthetic pain associated with MS.
It is not uncommon for a person to try different medications before finding one that is effective and tolerable. For example Carbamazepine appears to have a higher incidence of side effects, when compared to gabapentin and lamotrigine. Some people have difficulty tolerating this medication due to its side effects, and are not even able to reach the therapeutic dose necessary for the mediation to be effective.
Open communication with the neurologist is very important throughout this process.
In general, anticonvulsant medications, as well as tricyclic antidepressants, may be useful in some MS patients, although unfortunately there is not enough data to draw conclusions as to the best choice of medication.
Use of cold, pressure stockings or application of capsaicin ointment.
[Capsaicin is an extract of the Mexican red pepper. Capsaicin, for reasons still not completely understood, interferes with the action of Substance P, a nerve chemical that sends pain messages to the brain. 75% of users have reported relief from pain and it can also be used to relieve cluster headaches.]
Fortunately the understanding and measurement of MS-related pain has grown and improved enormously in the last 10 years. Continued research will help to provide the tools needed for doctors, nurses and therapists to help people with MS to manage their MS-related pain in new and effective ways.