Question: I understand that many older patients have joint replacements due to arthritis. It seems many young Cushing’s patients also have joint replacements. Is this due to arthritis or something else?
 
Answer: This is a great question. I have also noticed, anecdotally, that my Cushing’s patients seem to undergo more joint replacements than expected. Unfortunately little research has been done on the effects of glucocorticoids on joints. There are a few reported cases of polyarthropathy (arthritis present in 5 or more joints) associated with Cushing’s disease, including a case of ‘bony aseptic necrosis’ at multiple sites (published in BMJ in 1986). Ironically, glucocorticoids are commonly injected into joints to treat joint diseases like osteoarthritis (in people without Cushing’s of course). But the long term effects of these intra-aurticular glucocorticoid injections on joints are not clear.

A condition that has been shown to be associated with glucocorticoid exposure is avascular necrosis, also called osteonecrosis, which is basically death of the bone. This occurs more commonly in people exposed to exogenous glucocorticoids rather than those with endogenous Cushing’s syndrome. The most common location is the femoral head, the highest part of the thigh bone that forms the hip joint. Avascular necrosis has to do with the bone itself (not the joint) and interruption of the blood supply to the bone. Bone is an organ that needs blood supply and when the blood supply is interrupted, bone death occurs. Bone death could lead to the need for joint replacement. Of course it is well known that there is risk for thinning of bones (osteoporosis) due to Cushing’s, which is a separate issue than this question on joint replacement.

Finally, underlying arthritis that was previously ‘treated’ by the elevated glucocorticoids in active Cushing’s can be unmasked/exacerbated by Cushing’s treatment. A few reports have described the onset of rheumatoid arthritis, or other autoimmune conditions, only after successful Cushing’s treatment has occurred. This scenario should be differentiated from the joint aching and discomfort many patients experience transiently after surgical remission, as part of the constellation of relative adrenal insufficiency or steroid withdrawal symptoms.

By Dr. Eliza Geer, Mount Sinai Pituitary Center, NY, NY (Winter, 2015)