XIII: Diseases of the musculoskeletal system and connective tissue

M30-M36: Systemic connective tissue disorders

Systemic connective tissue disorders include a variety of conditions that affect the tissues that support the body's structures and organs. These disorders occur when the immune system mistakenly targets these connective tissues. Possible causes may include genetic factors, abnormal immune response, or even environmental triggers. Common symptoms across these conditions generally include fatigue, pain, and swelling in various bodily tissues, particularly in the joints and muscles. As these conditions affect the body's systemic connective tissues (such as the skin, muscles, ligaments, and tendons), they may impact numerous systems throughout the body, including the musculoskeletal, gastrointestinal, and cardiovascular systems. Disease progression can vary depending on the specific disorder and the affected individuals, but they often present as chronic, with periods of flare-ups and remission.