Cortisone is a naturally occurring hormone produced by the adrenal glands that is normally released in response to some form of stress. It also has a potent anti-inflammatory effect. Synthetic types of cortisone are more potent and longer acting, and are used in both diagnostic and treatment applications for a variety of bone and joint problems.
Synthetic cortisone may be injected directly into a joint to relieve pain and inflammation. There is a lag time for onset of action between 2-7 days, and the duration and degree of benefit is also variable between patients. The frequency of steroid injections is often limited by the associated risks, particularly of infection, tendon rupture, and cartilage damage.
The commonest adverse effect seen is known as a “cortisone flare”, where the injected cortisone crystallizes and causes acute severe pain, typically within 24-48 hours of the injection. It usually settles with simple measures such as analgesics and ice packs.
Other associated risks include:
- Infection at the injection site – This rare complication may have an associated fever, with pain, swelling, and redness at the injection site. Antibiotics may be necessary for management. If the injection has been into the joint, this may result in septic arthritis – an orthopaedic emergency that often requires a combination of surgical washout of the joint (this may be done arthroscopically) combined with antibiotics.
- Blood sugar elevation in patients with diabetes – The elevated sugar level may last for over a week, and insulin-dependent diabetics may need advice from their Endocrine specialist during this period.
- Facial redness and flushing – This tends to present 2-3 days post injection, and may last up to one week. It occasionally requires treatment with antihistamines.
- Tendon rupture – May occur if the steroid injection is given directly into a tendon.
- Superficial injections can be associated with localised skin and subcutaneous fat atrophy with hypopigmentation (a whitened area of skin at the injection site).
- Avascular necrosis (osteonecrosis) –Whilst this is more commonly associated with prolonged high dose steroid treatment (greater than 8mg Prednisone daily), it has been reported to idiosyncratically occur following solitary injection.
Any adverse outcome requires immediate contact to A/Prof Woodgate.