Pain in multiple sclerosis? Pain is not a symptom that is commonly associated with MS. But, when findings of worldwide MS research studies suggest that pain is a key factor in MS, it is important that people with MS and their families, friends, carers, MS society staff and health professionals, take a second look at the symptom of pain and its impact on the lives of people with MS. Such studies have revealed that approximately two thirds of people with MS experience pain at some time during the course of the disease; pain can be an early and presenting symptom; pain can be the most debilitating symptom, impacting function; pain is undertreated; and that pain is associated with depression, anxiety and fatigue.
Pain in MS - is this something new?
Indeed, knowledge of the experience of pain associated with the diagnosis of MS existed in the 1800’s as Jean Martin Charcot associated pain observed in patients with a neurological condition he termed insular sclerosis. In 1853, French neurologist Trousseau noted that pain had epilepsy-type characteristics, guiding scientists’ use of anticonvulsants, also known as antiepileptic drugs, to treat pain. Phenytoin was used to manage painful tonic spasms in the 1940s, and in the 1960s, several case studies and isolated reports of pain in MS emerged. Anticonvulsants were still first-line treatments at the time. It was not until the 1980s that the incidence, prevalence and characteristics of MS pain were described through findings from population-based studies conducted in North America and Europe. Associations of pain with other symptoms and the psychosocial implications were further explored in more recent studies. These studies supported pain as a common feature in MS and suggested ways of managing the symptom.
Why does pain occur in MS?
Pain is a sensory symptom directly related to two occurrences – the disruption of central nervous system myelin and the effects of disability. Myelin speeds nerve conduction, aiding smooth motor activity, integration and interpretation of sensory stimuli and effortless cognition. When pain is the result of a disruption or alteration of nerve conduction, it is termed neurogenic, or having its genesis or roots in the central nervous system. Some literature also uses the term 'neuropathic'. There is currently no agreement on which term is more correct.
Nociceptive pain occurs when bone, muscle or body nociceptors warn of tissue damage which may result from disability. This can be secondary to musculoskeletal changes in MS due to weakness or incorrect posture for example. If a person walks in a different way than normal then joints may be stressed and become painful as well. One of the side effects of steroids is bone loss but this is usually not an issue in MS as they are generally used for short periods. Immobility can result in a loss of bone density but this is not usually painful unless it results in a fracture. Nociceptive pain can also occur when skin breaks down or is expected to bear weight over an extended time without movement.
How does MS neurogenic pain present?
Neurogenic pain is described as continuous and steady or spontaneous and intermittent, and is reported in varying degrees of severity. One large North American study found that half of those reporting pain said their pain was continuous and severe. Intermittent, spontaneous pain is characterised as shooting, stabbing, electric shock-like, or searing and is often evoked by stimulus that normally do not cause pain, for example touch, the weight of bed covers, chewing or a cold breeze can all bring about spontaneous neurogenic pain.
Neurogenic pain described as steady is typified by burning, tingling, tight or band-like sensations, aching and throbbing. Steady neurogenic pain is often worse at night, worse during temperature change and worsened by exercise.
How can MS pain be treated?
Pain is an individualistic symptom that can only be described by the person experiencing it. Some altered daily functions, such as sleep, mood, and the ability to work, play and enjoy life, give clues as to the impact of pain on the lives of those who experience it.
Assessing the type and the cause of pain is important to appropriate pain treatment. Pain management is approached medically, behaviourally, physically and in some cases,surgically. Pain is complex and often requires a multidisciplinary approach and the skills of pain management experts.
Medication
If the cause is neurogenic, medications that modulate excitatory neurotransmitters and enhance inhibitory transmitters are prescribed.
Medications used in MS pain management include antidepressants and opioids because an increase in neurotransmitters minimises pain. MS pain is modulated with anticonvulsants and antiarrhythmics because they calm excited nerve firing.
Painful tonic spasms, or spasticity, are considered a secondary cause of pain in MS - pain due to a symptom rather than neurogenic. If the cause of pain is related to disability, meaning muscular or skeletal pain, pain from infection or skin ulcers, it is addressed using common analgesics, antispasmodic treatment or antibiotics, depending on the cause. The use of medications to manage pain in MS is always a balance of risk versus benefit. In other words, medication side effects are considered and continually evaluated in terms of their impact on a person’s quality of life.
Behavioural
Behavioural mechanisms for pain management include relaxation, meditation, imagery, hypnosis, distraction and biofeedback. Getting involved in work or social activities, joining a support group or even having a good laugh are proven mechanisms to minimise pain. Higher pain severity is reported by people with MS who are unemployed or homebound.
Physical
Physical agents that minimise pain include the application of heat, cold or pressure, physical therapy, exercise, massage, acupuncture, yoga, tai chi, and Transcutaneous Nerve Stimulation (TENS) These techniques and therapies are often overlooked but should be considered from the onset of pain symptoms.
Surgical
Surgical pain management interventions are sought when medical, physical and behavioural options fail. Procedures such as regional nerve blocks are reversible and safe. Neurosurgical options, rhizotomy, cordotomy, and Gamma Knife radiosurgery, are known to offer relief, but carry risks.
Summary
Today pain is recognised as a common symptom of MS directly related to the disease and its consequences. Symptom management is based on the mechanisms of the pain experienced. The direction and focus of continued research includes a better understanding of the mechanisms of pain in MS and its effective treatments. The following articles will provide further insight into the experience and management of pain in MS.
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