Dysfunction in the sacroiliac joint, also called the SI joint, can sometimes cause lower back and/or leg pain. Leg pain from sacroiliac joint dysfunction can be particularly difficult to differentiate from radiating leg pain caused by a lumbar disc herniation (sciatica) as they can feel quite similar.
Systemic lupus erythematosus (SLE), also known simply as lupus, is an autoimmune disease in which the bodyâs immune system mistakenly attacks healthy tissue in many parts of the body. Symptoms vary between people and may be mild to severe.
(It could become systemic if the infection spread.) Not all systemic diseases are infections. For example diabetes causes symptoms and changes throughout the body. It is an autoimmune disorder that is not caused by an infection, and it is a systemic disease. Cardiovascular disease is also a systemic disease.