Steroid-Induced Osteoporosis

Steroid-induced osteoporosis is osteoporosis arising due to use of glucocorticoids (steroid hormones) - analogous to Cushing's syndrome and involving mainly the axial skeleton. The synthetic glucocorticoid prescription drug prednisone is a main candidate after prolonged intake. Bisphosphonates are beneficial in reducing the risk of vertebral fractures. Some professional guidelines recommend prophylactic calcium and vitamin D supplementation in patients who take the equivalent of more than 30 mg hydrocortisone (7.5 mg of prednisolone), especially when this is in excess of three months. The use of thiazide diuretics, and gonadal hormone replacement has also been recommended, with the use of calcitonin, bisphosphonates, sodium fluoride or anabolic steroids also suggested in refractory cases. Alternate day use may not prevent this complication.

It is also known as glucocorticoid-induced osteoporosis.

Mechanism

Mechanisms of SIOP include:

• Direct inhibition of osteoblast function
• Direct enhancement of bone resorption
• Inhibition of gastrointestinal calcium absorption
• Increased urine calcium loss
• Inhibition of sex steroids

The combination of these changes leads to drug-induced nutrient depletion. Prednisone moderately depletes calcium, vitamin D, chromium and magnesium. This explains why the professional guidelines recommend calcium and vitamin D supplementation.

Diagnosis

The diagnosis of osteoporosis can be made using conventional radiography and by measuring the bone mineral density (BMD). The most popular method of measuring BMD is Dual-energy X-ray absorptiometry.

In addition to the detection of abnormal BMD, the diagnosis of osteoporosis requires investigations into potentially modifiable underlying causes; this may be done with blood tests. Depending on the likelihood of an underlying problem, investigations for cancer with metastasis to the bone, multiple myeloma, Cushing's disease and other above-mentioned causes may be performed.