Corticosteroid injections cause a non-specific dampening of the inflammatory response produced by inflamed or arthritic joints and tissues, potentially providing short term pain relief. While such injections are not a permanent solution, since the underlying condition causing the inflammation remains unchanged, treatment of the symptoms enable patients to break the cycle of immobilization long enough to have the potential to restore range of motion and build strength in order to improve function in the long term.
What are Corticosteroids?
Corticosteroids are a class of steroid hormone produced in the adrenal cortex involved with a wide range of physiological systems. Glucocorticoids such as cortisol control carbohydrate, fat and protein metabolism and reduce inflammation by preventing phospholipid release, decreasing eosinophil action and other mechanisms. Cortisone, a common natural hormone, is a type of corticosteroid.
When are Corticosteroid injections indicated?
Injection of a corticosteroid, like cortisone, into an inflamed or arthritic joint or an inflamed area of tissue such as a tendon or nerve may provide some short – or intermediate-term pain relief. This pain relief occurs by settling down the body’s inflammation response, thereby decreasing the pain response (less inflammation often correlates with less pain). The decrease in inflammation and pain will ideally lead to improved function.
In general, care must be taken when injecting corticosteroids around tendons since corticosteroids tend to weaken the tendons, possibly predisposing them to rupture. While cortisone injections may decrease symptoms, they do not change the underlying pathology created by issues liked overloading. For example, if a patient has tendonitis or arthritis they will still have the same condition after the injection, although hopefully the symptoms from this condition will be improved. Injections just help break the cycle and allow patients to get things moving a little better. Eventually, if the underlying cause of the problem is not addressed the symptoms are likely to return.
How the injection is performed
The corticosteroid injection is carried out in the doctor’s office. The skin is sterilized prior to the injection (usually with betadine or alcohol) and the needle is injected into the area by feel or sometimes using fluoroscopy. Fluroscopy is an imaging technique commonly used by physicians to obtain real-time moving images of the internal structures of a patient through the use of an x-ray source and a fluorescent screen. If a joint is being injected and there is an excessive amount of fluid within the joint, the doctor may remove it prior to the injection to relieve pain by reducing the pressure of the fluid within the joint. Often, the steroid is injected with a local anesthetic like lidocaine to provided short term numbing of the area. The anesthetic typically wears off within a few hours.
This is why it is common for patients to experience worsening symptoms over the next few days before noting improvement. Injections are relatively easy to administer, take effect more rapidly than traditional anti-inflammatory medications, and avoid side effects that often accompany them like stomach irritation.
Cortisone injection has variable levels of effectiveness. Some patients enjoy successful results for up a number of months while others may see entirely no change. Injections are typically limited to 2-4 per year. Routine regular injections should probably be avoided if possible because each injection tends to weaken the tissue. Minimizing the inflammatory response (which is what the injections do) tends to inhibits the natural healing process. Over time, the effectiveness of the injections may diminish. Therefore, more injections do not necessarily result in greater benefits.
Potential risks of Corticosteroid injections
Long term potential side effects may include thinning of the skin, bruising, an increase in local pain, and atrophy of the tissue around the injection site. There is also the risk that the corticosteroid may actually increase the rate of cartilage breakdown in the joint or weaken tendons that are injected. It is also possible for patients to have an increased inflammation in response to a corticosteroid injection that has crystallized. Finally there is always a slight risk of infection with any kind of injection. While infections as a result of injections are rare they can be very serious. As an example if an arthritic ankle joint becomes infected following a corticosteroid injection it may preclude the patient from ever undergoing a total ankle replacement as a history of a deep infection is a relative contraindication for this procedure. However, the chance of an infection is minimal if the skin adequately disinfected, sterile technique is used, and there is no local infection around the injection site. Injections may elevate blood sugar levels for patients with diabetes.
Edited July 16th, 2014