Cortisone (Cortico-steroid) Injection

What is cortisone?

Cortisone is a type of steroid that is produced naturally by a gland in your body called the adrenal gland. Cortisone is released from the adrenal gland when your body is under stress. Natural cortisone is released into the blood stream and is relatively short-acting.

Injectable cortisone is synthetically produced and has many different trade names (e.g. Celestone, Kenalog, etc.), but is a close derivative of your body’s own product. The most significant differences are 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).

What are some common reasons for a cortisone injection?

Many conditions where inflammation is an underlying problem are amenable to cortisone shots. These include, but are certainly not limited to

  1. Shoulder Bursitis
  2. Arthritis (alternative injection options available – see Ostinel Injections)
  3. Frozen Shoulder • Rotator Cuff Pathology
  4. Trigger Finger
  5. Tennis Elbow
  6. Carpal Tunnel Syndrome

How does the cortisone injection help?

Commonly, people wrongly have the impression that cortisone injections merely mask the problem. This is not the case. Cortisone is a powerful anti-inflammatory medication. Cortisone is not a pain relieving medication, it only treats the inflammation. When pain is decreased from cortisone it is because the inflammation is diminished. 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 within a few days, and the effects can last up to several weeks. This gives us the ‘window’ to start and progress your rehabilitation in a timely fashion, through from expertise assessment and diagnosis through to resolution.

Does the cortisone injection hurt?

The injection can be slightly uncomfortable, especially when given into a joint, but in skilled hands it usually is well tolerated. Often the cortisone injection can be performed with a very small needle that causes little discomfort. However, sometimes a slightly larger needle must be used, especially if your physician is attempting to remove fluid through the needle prior to injecting the cortisone. Numbing medication, such as Lidocaine or Marcaine (local anaesthetic), is often injected with the cortisone to provide temporary relief of the affected area. Also, topical anaesthetics can help numb the skin in an area being injected. These injections can be ultrasound guided if necessary, helping to ensure accurate placement in sensitive areas.

Can I get a cortisone injection more than once?

Yes. There is no rule as to how many cortisone injections can be given. Often physicians do not want to give more than three in one area, but there is not really a specific limit to the number of injections. 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.

Are there side effects?

Probably 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. 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. Other side-effects of cortisone injections, although rare, can be more serious. The most concerning 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. However, it is possible to be allergic to other aspects of the injection, most commonly the local anaesthetic used to mix with the steroid. This is relatively rare, and if you have had injections with the dentist before with no side effects then you should be at no risk of allergic reaction to a cortisone injection.

Sources: 
Cole BJ and Schumacher HR “Injectable Corticosteroids in Modern Practice” J. Am. Acad. Ortho. Surg., January/February 2005; 13: 37 – 46.
Fadale PD and Wiggins ME “Corticosteroid Injections: Their Use and Abuse” J. Am. Acad. Ortho. Surg., May 1994; 2: 133 – 140.
Cited from: http://orthopedics.about.com/cs/paindrugs/a/cortisone.htm