Osteomalacia

Question 1

What is osteomalacia?

Answer 1

Osteomalacia describes softening of the bones secondary to low vitamin D levels that lead to decreased bone mineral content. If this occurs in growing children, it is referred to as rickets, with the term osteomalacia preferred for adults.

Question 2

What are the causes of osteomalacia?

Answer 2

Causes include vitamin D deficiency, malabsorption, lack of sunlight, diet, chronic kidney disease, drug-induced (e.g. anticonvulsants), inherited conditions (e.g. hypophosphatemic rickets), liver disease (e.g. cirrhosis), and coeliac disease.

Question 3

What are the features of osteomalacia?

Answer 3

Features include bone pain, bone/muscle tenderness, fractures (especially femoral neck), and proximal myopathy which may lead to a waddling gait.

Question 4

What investigations are used for osteomalacia?

Answer 4

Investigations include blood tests showing low vitamin D levels, low calcium and phosphate (in around 30%), and raised alkaline phosphatase (in 95-100% of patients). X-rays may show translucent bands (Looser’s zones or pseudofractures).

Question 5

What is the treatment for osteomalacia?

Answer 5

Treatment includes vitamin D supplementation, often requiring an initial loading dose, and calcium supplementation if dietary calcium is inadequate.