I've suffered from mild arthritis for some years but lately one of my knees has become more painful and swollen. I have been referred to a rheumatologist and will be having the joint injected with something called corticosteroid. Can you tell me what this drug is and how it will work?
Corticosteroid is a hormone naturally produced by the adrenal gland, which lies on top of the kidneys. In addition to its other actions, it plays an important role by influencing the immune system. A number of drugs have been developed which mimic the action of natural corticosteroids, and have been shown to be particularly effective in the treatment of joint disorders - particularly osteoarthritis and rheumatoid arthritis.
The steroid can be injected into the affected joint(s) and helps by relieving pain and reducing inflammation. It is also a useful treatment option for strained muscles, ligaments or tendons, as in the case of tennis elbow or frozen shoulder.
Corticosteroids are believed to have two main actions that are thought to account for their effectiveness. The first is their ability to block prostaglandins - the chemicals that trigger inflammation and pain in the body - and secondly they depress the activity and accumulation of white blood cells that cause inflammation.
But injecting into the joint . . . won't that hurt?
Injecting directly into the site of the problem gives maximum benefit where it is most needed. Corticosteroids usually produce dramatic relief from symptoms when injected into the affected joint. Although it may feel a little uncomfortable during the procedure, a skilled physician should be able to carry it out quickly and effectively with little pain.
Should I be worried about potential side effects?
As opposed to steroids that are taken orally, injected steroids are generally confined to the affected area rather than dispersed in significant amounts throughout the body. This means that the side effects usually associated with steroid treatment are unlikely to occur. Sometimes, however, a loss of skin pigmentation over the injection site may be noticed or occasionally a temporary increase of pain - known as a steroid flare - may occur, but this usually resolves with rest, ice and oral painkillers.