RA Can Attack Connective Tissues in the Musculoskeletal System
In an earlier post, I outlined how RA can impact much more than bones including many organs and soft tissues. One group of soft tissues that can be damaged by RA includes those involved with the musculoskeletal system. The musculoskeletal system involves a complex interaction between muscles, bones, joints, and various connective soft tissues – all which can be the target of RA.
Can RA cause soft tissue damage?
Erosion of bone tissues in joints is one of the trademark symptoms of rheumatoid arthritis. Through complex autoimmune biochemical processes, the body’s immune system attacks its own tissues like it was a foreign invader. A cascade of signaling chemicals promotes the production of bone cells called osteoclasts that erode bone tissue and surrounding cartilage. This kind of gross damage shows up on medical imaging of joints and is used as a tool for diagnosing RA and for tracking the effectiveness of treatments. But in addition to hard bone, RA can also attack the associated soft connective tissues.
The synovium is a complex sac-like system that surrounds certain joints in the body. It contains a wide variety of cells and tissues including blood, lymph cells, proteins, multiple biochemicals, and fluid.1 It helps to maintain lubrication of the joint. Unfortunately, it is one of the main targets in inflammatory autoimmune diseases like RA. During an autoimmune attack, the synovium can swell and contain an overabundance of inflammatory proteins called cytokines that turn on destructive processes, resulting in the break down of bone and cartilage.
Bone damage around synovium
It’s common for bones and cartilage around synovium to become damaged from RA. One of the first symptoms that led me to a rheumatologist was swelling in every middle joint of my fingers (called metacarpophalangeal or MCP joints). By the time an x-ray was taken, there was already bone erosion seen around the synovium.
Cartilage is soft, flexible connective tissue that occurs in various parts of the body including in the ears, nose, and joints. In joints, it occurs between bones to keep them from rubbing on each other. This type of cartilage is called articular.2 Articular cartilage can be damaged from physical activity like a meniscus tear in the knee during sports, breakdown from normal wear and tear like in osteoarthritis, or as the result of the destructive biochemical processes in autoimmune diseases like RA.
Treating cartilage damage
About the time of my RA diagnosis, I already had several years of knee pain. An MRI revealed damage to the articular cartilage including torn flaps of cartilage that cause my knee to lock up in pain. There are numerous accepted procedures for treating articular cartilage damage including steroid injections, microfracture, drilling, autograft transplant, and stem cells. If cartilage tears away to the point that bone is rubbing on bone, then a knee replacement may be necessary. This is a rather common surgical procedure with RA patients.
Tendons and ligaments
Tendons are connective tissue that holds muscles to bones. Chronic tenosynovitis, inflammation of the sheath of a tendon, is common in rheumatoid arthritis and can result in the permanent damage and tearing of the involved tendons. Such tendon problems caused by RA are well known by the scientific community and are linked to joint deformities.3,4 Tendon problems have even been posited as being one of the most powerful predictors of early RA.5 Sophisticated imaging techniques developed in the last few decades, such as MRIs and ultrasound, can reveal connective tissue damage in joints caused from RA including tenosynovitis and bursitis.6 Bursitis, inflammation of the fluid-filled sacs that protect joints, often accompanies tenosynovitis.7
Ligaments are connective tissue that holds bones to other bones.8 Since they tend to be in the area of a joint near the synovium, they are also subject to the destructive processes of RA. The breakdown of tendons and ligaments during RA is primarily through a process called enthesitis that involves the breakdown of the place where ligaments and tendons attach to bone.9
Soft tissue problems prior to diagnosis
Tendon problems have been one of the hallmarks of my struggles with RA. One of the first symptoms I experienced, even before official diagnosis, was Achilles tendon tearing in both ankles that resulted in three surgeries. The last surgery involved the removal of a bursa sac, reattaching the tendon to my heal bone, removal of damaged tendon tissue, and removal of a bone spur caused by a dime-sized bone erosion. Even after those procedures, my Achilles tendons continue to yell at me rather loudly everyday. I am now dealing with a 50% torn extensor tendon in my elbow and am facing surgery for that after steroid injections and physical therapy did not help.
Be aware of damage to cartilage, tendons, and ligaments
RA patients and doctors need to be aware of, and watchful of RA damage to cartilage, tendons, and ligaments. It can cause serious and debilitating destruction to the musculoskeletal system resulting in reduction of physical functioning, surgeries, and disability. Many, RA patients show connective tissue damage and genetics may play a role in what type of tissues are attacked by RA processes.10 Since the damage to these tissues can occur early in the disease progression, it is critical to diagnosis and treat RA as early as possible.
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