What is seronegative rheumatoid arthritis?

The autoimmune disease, seronegative rheumatoid arthritis, can produce the same symptoms as rheumatoid arthritis (RA), although blood samples usually do not show the rheumatoid factor (RF) commonly associated with the disorder. Up to 20 percent of patients with this chronic inflammatory disease do not initially exhibit RF, although some eventually become seropositive, producing the factor as the disease progresses. Joint swelling, pain, and damage usually occur in advanced cases, and other body systems may also be involved. Health care providers generally treat seronegative rheumatoid arthritis based on symptoms and disease progression.

Seronegative rheumatoid arthritis begins with cellular and humoral immune responses in the body. White blood cells in the bone marrow and thymus begin to produce antibodies. These white blood cells and the chemicals they produce invade body tissue, especially the joints. The first symptoms of seronegative rheumatoid arthritis usually occur months before joint involvement and typically include depression, fatigue, and malaise, which may be accompanied by a low-grade fever. After two to three months, patients experience swelling, pain, and tenderness in a joint.

As the disease progresses, more limb joints are involved. Morning stiffness and joint pain continue for a period of hours, a symptom that usually differentiates RA from other types of arthritis. Seronegative rheumatoid arthritis usually causes joint swelling and tenderness along with warmth and pain when moving. These symptoms occur because the autoimmune response causes inflammation of the tendon which can lead to the formation of cysts and eventual ruptures of the connective tissue. Usually within two years of onset, connective tissue loss causes erosion and proliferation of bone cells, resulting in joint deformities.

The swelling and inflammation commonly associated with seronegative rheumatoid arthritis can also compress sensitive nerve tissue, causing nerve pain. Patients may also experience symptoms related to muscle involvement. The autoimmune response can progress to eventually affect the heart and lung systems, causing inflammation, fluid buildup, and tissue fibrosis. Some develop a condition known as Sjogren's syndrome, in which white blood cells infiltrate the lacrimal, salivary, and exocrine glands, inhibiting the normal flow of body fluids.

Definitive diagnosis of seronegative rheumatoid arthritis is often challenging in the early stages. Not only do patients not exhibit RF in blood samples, but symptoms can come and go. People may experience a flare of symptoms for 24 to 48 hours followed by complete resolution. Some people have a complete remission within six months of the onset of initial symptoms. The development of the anti-citrullinated protein (anti-CPP) antibody blood test has helped identify the disease in some patients who do not usually produce RF.

Health care providers typically prescribe medications for seronegative rheumatoid arthritis that correlate with symptoms. Nonsteroidal anti-inflammatory drugs and corticosteroids usually help reduce inflammation and swelling. If x-rays indicate joint space narrowing, doctors may administer disease-modifying antirheumatoid drugs, also known as DMARDS, to reduce the risk of joint damage and deformity.

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