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Why might rheumatoid arthritis cause fatigue, weakness, and weight loss?

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Rheumatoid arthritis is a chronic autoimmune disease characterized by systemic inflammation that affects the body's connective tissues, particularly the synovial membranes of the joints.12

The systemic nature of this inflammatory process is the primary reason for constitutional symptoms like fatigue, muscle weakness, and weight loss. Because the immune system is actively attacking the body's own tissues, the resulting chronic inflammation can lead to anemia and general physiological stress. Furthermore, the disease causes atrophy in the muscles and bones adjacent to affected joints, often due to disuse resulting from pain and stiffness. These factors collectively contribute to the weakness and weight loss frequently observed in patients.12

While the exact trigger for this autoimmune response remains unknown, the persistent inflammatory state significantly impacts overall health beyond the localized joint damage.1