Corticosteroids (CTSs) have not had the best press recently for all sorts of reasons. Just to be clear the term ‘corticosteroids’ specifically refers to a class of drug used to treat arthritis and other inflammatory conditions. CSTs often get referred to as ‘steroids’ and many of us get this term confused with anabolic steroids that have been used to boost strength and physical performance. We only need to look at a host of modern sporting household names such as Lance Armstrong and a whole host of 100m runners (and Russian athletes!!) for making this a commonly mis-understood term. It is important to get that bit out of the way!
Many of us are prescribed CSTs such as prednisone for various rheumatological conditions such as Polymyalgia Rheumatica (PMR) or triamcinolone for osteoarthritic joint pain. However, there is increasing evidence that the use of CTSs for OA may not actually be a good thing. In this short article I have decided to have a quick look at CSTs and address where they came from, what they do and have a quick look briefly at some recent research study.
Corticosteroids (CST) were first isolated in the 1930’s from bovine adrenal glands by a biochemist called Edward Kendall. There were also rumours in World War Two that German pilots were given CSTs so that they could fly at high altitudes without suffering from hypoxia (lack of oxygen). Back in time CSTs were officially trialled on a group of patients in 1948 at the Mayo clinic in Rochester, Minnesota in the U.S. One patient in particular, with severe rheumatoid arthritis and acute debilitating joint immobility, was injected with CSTs and within a couple of days was able to enjoy a three-hour walk. CSTs were thus regarded as a modern miracle!! The two scientists Edward Kendall and Philip Hench involved in the trial were awarded the Nobel Prize for Physiology and Medicine in 1950 with a Swiss scientist (Tadeus Reichstein) who had also independent research and identified CTSs at the same time.
Steroid is a term to describe a biologically active compound with a specific structure (I won’t bore you with the detail!). The function of steroids is fundamental to every cell in your body. In terms of cell physiology, they play an important role in the integrity of every cell membrane and they activate receptors on a cell’s surface to regulate how it behaves in a given set of circumstances.
In broad terms there are different types of steroids in nature. There are reproductive steroids that we all know (oestrogen, progesterone and testosterone), neurosteroids which help produce these three hormones, secosteroids such as Vitamin D (important in bone density), sterols (such as cholesterol which are important in cell membranes) and lastly corticosteroids (such as cortisol and aldosterone). We are interested specifically in corticosteroids and man-made drugs that closely resemble cortisol.
So what biological role does cortisol have? When our bodies are exposed to stress, our pituitary gland release adrenocorticotropic hormone (or ACTH). ACTH stimulates our adrenal glands to produce cortisol. Cortisol plays an important part in controlling electrolyte balance in the body as well as regulating carbohydrate, fat, and protein metabolism. Our adrenal gland, under normal circumstances produces about 20mg of cortisol per day but it can produce much more if required (more than five times this amount). This is indexed to stress factors such as trauma, infection or emotion. This extra cortisol will influence the immune system by blocking the release of various substances (such as prostaglandin) that trigger an inflammatory response. One trade-off is that they also limit the action of white blood cells which help regulate your immune system. You can thus be more susceptible to infection.
CTSs are usually given systemically (to treat our whole body) or locally to a precise location (e.g. a joint injection) such as an osteoarthritic joint. The use of CSTs for osteoarthritis is an area of ongoing contention. Osteoarthritis, as we know, is a disease associated with a breakdown of cartilage in our joints. When the joint loses cartilage, the body responds by growing bone abnormally leading to change in structure and function. This results in the bone becoming mis-shapen and the joint painful and unstable. This can affect physical function and the ability to use the joint. Many of us are offered CTS injections for arthritic joint pain but is this supported by actual evidence. Certainly for some conditions such as Frozen Shoulder (and some soft tissue conditions) CTS injection can certainly help with pain management. However what actual difference do CTS injections make with arthritic pain and joint function.
In 2015 there was Cochrane review (updating a previous review from 2005) on CST injections for knee joint arthritis. For those of us who don’t know one of the gold standard reviews is a Cochrane review. Cochrane is a global independent network of researchers, professionals, patients, carers and people interested in health. This reviewed 27 trails which included 1767 participants with the idea of determining the benefits or harm of CST injections relative to pain, physical function, quality of life and safety. The review of these trials concluded that it was ‘unclear whether there are clinically important benefits of intra-articular CSTs after one to six weeks’ and that the quality of evidence was low and ‘generally highly discordant’.
A recent paper (by Jacqui Wise) from 2017 published in the British Medical Journal looked at joint injections into knee joints. This study looked at 140 patients (average age 58) who had knee OA. These patients all received 40mg of triamcinolone or saline (as placebo) every 12 weeks for 2 years. At the end of the study they found no difference in pain between the two groups but they did find a much higher volume of cartilage loss in those that received triamcinolone “The results of the studies do not support the use of long term repeated corticosteroid injections for the management of pain or structural progression in osteoarthritis, and in fact indicate that there may be more cartilage loss in people who receive steroids.”