Just when you thought you knew all there was to know about rheumatoid disease, I barge in to tell you more. Today’s subject: how it may affect your nerves.
Yes, I know RD can get on your nerves. Frequently unpredictable, often miserable pain and fatigue can test the mettle of even the toughest among us. But in this case I’m talking about neuropathy. The Merriam-Webster online dictionary defines it this way: “An abnormal and usually degenerative state of the nervous system or nerves.” The word comes from the Greek: neuro: nerve; pathy: disease.
Well, that fits right in with rheumatoid disease, which is also abnormal and usually degenerative, right?
Neuropathy is a common problem for those with chronic illnesses, in particular Type 1 (autoimmune) and Type 2 (acquired) diabetes. Unfortunately, it’s common among patients with rheumatic diseases, as well. The difference is mainly in the method of destruction.
RD is an autoimmune disease, meaning that the body’s immune system, which works to protect it against foreign invaders like bacteria and viruses, mistakes its own tissues for mortal enemies. It primarily affects the synovial joints, but can also affect soft tissues like the linings of the heart and lungs, the vascular system, the kidneys, and the eyes. It sends out waves of ferocious, soldier-like antibodies to neutralize or destroy its perceived enemies.
But these tiny armies—like armies everywhere–don’t confine their destruction to just one spot. They’re imprecise and messy, so there’s a lot of collateral damage. RD affects the synovium—the fluid-filled capsule that encloses and cushions the joint—but it can also does a lot of damage to the soft tissues surrounding the joint, like tendons, ligaments, cartilage, muscles, and even nerves.
The most commonly seen neuropathies associated with RD are carpal tunnel syndrome in the hands, tarsal tunnel syndrome in the foot, ulnar nerve entrapment (elbow and wrist), and small-fiber neuropathy. And while it’s rare, patients who take leflunomide, a DMARD, or one of the TNF-blocking biologic DMARDs, may be at risk for medication-induced neuropathies.
Carpal and tarsal tunnel syndromes involve nerves in the hands or feet that run between the carpal or tarsal bones. Most of us have heard of the carpal form. It’s a repetition injury mainly associated with people who spend long hours typing on a keyboard or doing other repetitious tasks. With RD, however, these syndromes are caused by inflammation and swelling.
Rheumatoid pannus, a type of thickened granulation tissue that sometimes forms in the synovial capsule in response to inflammation, can also cause neuropathy. The pannus may eventually break through the synovial membrane and flow into the surrounding areas. The pannus hardens and can impinge and compress nerves.
There is good news, though. In general, neuropathy caused by rheumatoid disease is mild. If you’re experiencing what feels like neuropathic pain in your feet or hands, talk to your rheumatologist. There are effective drugs available that can relieve the pain. You and your doctor can also explore other options for treating it.