OSTEOMALACIA

Question 1

What is OM?

Answer 1

• there is a normal amount of bone but its mineral content is LOW (there is excess uncalcified osteoid and cartilage) - defective mineralisation
• reverse of osteoporosis

Question 2

What is rickets and how is OM different?

Answer 2

• defective mineralisation during bone growth at the epiphyseal growth plate
• Osteomalacia is defective mineralisation AFTER FUSION of the epiphyses i.e. in adults
• both are manifestations of profound vit D deficiency

Question 3

What is the most common cause of OM?

Answer 3

hypophosphataemia due to hyperparathyroidism secondary to vitamin D deficiency

Question 4

What can cause Vit D deficiency?

Answer 4

• Due to malabsorption, since vitamin D is fat soluble so GI disease can result in malabsorption e.g. in Coeliac or Crohn’s
• Poor diet - not enough oily fish or egg yolks
• Lack of sunlight

Question 5

What are other causes of OM?

Answer 5

• Renal disease:
• Drug induced eg anticonvulsants, rifampicin
• Liver disease:e.g. cirrhosis
• Tumour induced osteomalacia

Question 6

What are the signs & symptoms of OM?

Answer 6

• Muscle weakness - leading to characteristic waddling gait and difficulty climbing stairs and getting out of a chair
• Widespread bone pain - dull ache that is worse on weight-bearing and walking
• Bone pain and tenderness
• Fractures especially of the femoral neck

Question 7

What are the signs & symptoms of rickets?

Answer 7

• Growth retardation, hypotonia
• Knock knees, bowed legs
• Widened epiphyses at the wrists
• Hypocalcaemic tetany (intermittent muscular spasms) may occur in severe cases

Question 8

What are the investigations for OM?

Answer 8

• Bloods; low Ca and phosphate, raised ALP and PTH, low 25-hydroxy vit D
• Biopsy: Shows incomplete mineralisation, GOLD STANDARD TEST but not practical
• X-ray:Shows defective mineralisation and Looser’s pseudofractures/zones

Question 9

What is the treatment for OM?

Answer 9

Vitamin D replacement:

• In dietary insufficiency - Calcium D3 Forte
• In malabsorption/hepatic disease: Oral Ergocalciferol or IM Calcitriol
• In renal disease: Alfacidol or Calcitriol

Question 10

What else other than OM and rickets can Vit D deficiency lead to?

Answer 10

associated with increased risk of type 2 diabetes mellitus, several cancers and cardiovascular disease and should be treated