Your body naturally makes its own cortisone when your body is under stress this is called cortisol. It is a type of steroid that is produced naturally by your adrenal gland and is released when your body is under stress.
Injectable cortisone is synthetically produced but is a derivative of your body’s own product. One of the differences though is that synthetic cortisone is not injected into the blood stream, but into a particular area of inflammation. Also, the synthetic cortisone is designed to act more potently and for a longer period of time (days instead of minutes).
Cortisone is a strong anti-inflammatory medication. Cortisone only treats the inflammation. When pain is decreased from cortisone it is because the inflammation is decreased. By injecting the cortisone into a particular area of inflammation, very high concentrations of the medication can be given while keeping potential side-effects to a minimum. Cortisone injections usually work in 3 days but can take up to 2 weeks to work, and the effects can last up to a month. Many times once the inflammation is gone, the pain will stay away.
Many conditions where inflammation is an underlying problem are amenable to cortisone shots. These include, but are certainly not limited to:
- Shoulder Impingement
- Partial rotator cuff tear
- Calcific tendonitis
- Arthritis of the shoulder, hip, knee or spine
- Tennis or golfers elbow
- Bursitis of the knee or hip
- Plantar fascitis
- Trigger points
- Trigger finger
- Carpal tunnel
The shot can be slightly painful, especially when given into a joint, but in skilled hands it is well tolerated. Often the cortisone injection can be performed with a very small needle that causes little discomfort. Numbing medication, is often injected with the cortisone to provide temporary relief of the affected area. Also, topical anesthetics can help numb the skin in an area being injected. The most common side-effect is a ‘cortisone flare,’ a condition where the injected cortisone crystallizes and can cause a brief period of pain worse than before the shot. This usually lasts a day or two and is best treated by icing the injected area and taking an oral anti- inflammatory like motrin or aleve. Another common side-effect is whitening of the skin where the injection is given. This is only a concern in people with darker skin, and is not harmful, but patients should be aware of this. Some patients will have flushing of the face that can last for hours to a couple of days and then will resolve. The most concerning risk of an injection, is infection, especially if the injection is given into a joint. The best prevention is careful injection technique, with sterilization of the skin using iodine and/or alcohol. Also, patients with diabetes may have a transient increase in their blood sugar which they should watch for closely.
Because cortisone is a naturally occurring substance, true allergic responses to the injected substance do not occur.
Often physicians do not want to give more than three cortisone injections within a year, but there is not a specific limit to the number of shots. However, there are some practical limitations. If a cortisone injection wears off quickly or does not help the problem, then repeating it may not be worthwhile. Also, animal studies have shown effects of weakening of tendons and softening of cartilage with cortisone injections. Repeated cortisone injections multiply these effects and increase the risk of potential problems. This is the reason many physicians limit the number of injections they offer to a patient.