People with multiple sclerosis (MS) commonly experience a low pain threshold and sensitivity to heat and cold. If a person has multiple sclerosis along with fibromyalgia (FM), that could make this sensitivity even more intense. Until now, no group has studied this phenomenon.
In a study titled “Chronic Pain in Multiple Sclerosis Patients: Utility of Sensory Quantitative Testing in Patients with Fibromyalgia Comorbidity,” published in the journal European Neurology, researchers from Rome, Italy have investigated the effects of co-existing MS and FM on pain sensitivity thresholds.
MS is an autoimmune disease in which the body attacks myelin, the fatty covering that surrounds nerve cell fibers. This prevents effective communication in the nervous system between cells, and chronic pain is a major symptom. Loss of movement, loss of vision and problems with sensation can also result.
FM is characterized by chronic pain, fatigue, sleep, memory and mood disturbances. Symptoms can start following a physical trauma, significant psychological stress, surgery or illness. In other instances, there is no clear trigger and symptoms increase over time.
Led by Alessandra Pompa of the Fondazione Santa Lucia in Rome, the researchers studied 133 people with MS patients and possible chronic pain. They measured whether or not the participants also had FM based on the 1990 ACR diagnostic criteria. The scientists used a device known as an algometer to measure the pain threshold in the participants and in 60 healthy subjects who did not have MS. An algometer detects the minimum pressure needed to induce pain and discomfort in a patient’s body.
The researchers identified chronic pain in 88 (66.2%) patients. Of these, 12 (13.6%) had neuropathic pain. A total of 22 (17.3%) had FM-related pain and 65 (48.9%) had pain related to MS but not FM. The individuals with FM related pain were primarily women. Pain thresholds were lower in MS patients than controls, and low pain thresholds were more often found in the group with FM-related pain. FM severity was related to the threshold for temperature, and female gender was related to a lower discomfort threshold. These effects were all statistically significant.
In their study report, the researchers concluded that “Thermal and discomfort thresholds were lower in patients than controls and were the lowest in [people with fibromyalgia-related pain]. Their more severely impaired thermal threshold supports a neurophysiological basis of such association.”
This study indicates that people with both MS and FM can experience more pain. Pain management should be a particular focus of treatment in people with both conditions, but particularly if they have the two conditions at the same time.