The Similarities Between Fibromyalgia and Multiple Sclerosis

Is fibromyalgia more like multiple sclerosis (MS) than we thought? A unique line of research is highlighting some similarities in the disease processes related to immunity. Increased understanding of these features of fibromyalgia may eventually help lead to effective ways of managing the condition.

This article will explain the similarities and differences between fibromyalgia and MS.

Multiple Sclerosis Basics

MS is believed to be an autoimmune disease, which means the immune system is attacking parts of a person's own body. In MS, the symptoms are caused by demyelination, which means that the immune system is destroying a material In the body called myelin.

Myelin is a specialized cell that forms a sheath around some nerves and is necessary for those nerves to function properly. It works In a way that's similar to insulation on electrical wires. Areas where the myelin sheath is destroyed are sometimes referred to as lesions.

Some symptoms of MS and fibromyalgia are similar—fatigue, sleep difficulties, and fluctuations of symptoms.

But MS causes focal neurological deficits, which are defined as corresponding to areas of brain, optic nerve, or spinal cord demyelination. Specific diagnostic criteria for MS include evidence of lesions on diagnostic imaging tests, and blood tests or cerebrospinal fluid tests that may support the diagnosis.

Fibromyalgia is not associated with any focal neurological deficits or specific changes on diagnostic tests—but that doesn't make the condition any less real.

Fibromyalgia and Demyelination

The first study of fibromyalgia and demyelination came out in the journal Rheumatology in 2008, and the follow-up was published in a 2014 issue of Arthritis & Rheumatology.

The 2008 research suggested that a subset of fibromyalgia involved autoimmune demyelination and polyneuropathy (damaged peripheral nerves). It compared fibromyalgia to a neurological illness called chronic inflammatory demyelinating polyneuropathy, which is often treated with intravenous immunoglobulin (IVIg).

In fact, in that study, they used IVIg to treat people from this fibromyalgia subgroup. Granted, it was a small study, and only 15 people were treated, but researchers reported that those people had significantly less pain and tenderness, improved strength, and smaller improvements in fatigue and stiffness.

Fibromyalgia and Neuropathy

In the follow-up 2014 study, the researchers wanted to explore whether the nerve demyelination was caused by autoimmunity. Then, they wanted to explore small fiber neuropathy, which other studies have suggested is involved in fibromyalgia.

Small fiber neuropathy is painful damage to small nerves in the skin and organs that allow you to feel and help regulate automatic functions, like heart rate and body temperature.

The researchers found indicators of small fiber neuropathy, including diminished feeling in the lower legs. They also found that indicators of autoimmune activity were elevated. Immune activation appeared to be linked to a marker of immune activation called interleukine-2R.

Another, more recent study from 2019 found damage to large peripheral nerves associated with both demyelination and axonal damage In fibromyalgia. Axonal damage is damage to nerve tissue, which is normally enclosed within the myelin.

Putting It in Context

Taken in context, this work adds to the emerging picture that we do have damaged nerves after all, that our peripheral nervous systems are involved, and that autoimmunity or another aspect of immunity is at work.

A key difference between the demyelination In MS and the demyelination In fibromyalgia is that fibromyalgia demyelination affects peripheral nerves, while the demyelination of MS affects nerves of the central nervous system (brain and spinal cord).

A Word From Verywell

Learning that their condition is similar to MS could have real benefits for people with fibromyalgia. First, most people know what MS is and respect it as a serious condition. That could lead to better public acceptance plus more universal acceptance in the medical community. That, in turn, could lead to more research.

Research may provide a new avenue of prevention or treatment for fibromyalgia. It's likely that we'll continue learning more about this topic and that exciting things may come of it.