osteoporosis

Question 1

bone format?

Answer 1

Composite material with organic and inorganic phase •70% is mineral •30% extracellular matrix •bone is cellular and vascular •bone is constantly resorbed and reformed - bone turnover •normal bone is v strong and not brittle

Question 2

different areas of the bone and their function?

Answer 2

Cortical (compact) bone –x4 mass of trabecular –mechanical and protective function •Trabecular (cancellous or spongy) –metabolic function •Calcium homeostasis –x8 higher metabolic turnover

Question 3

secondary causes of osteoporosis?

Answer 3

Endocrine •thyrotoxicosis •hypogonadism •hyperparathyroidism •Cushing’s disease •Vitamin D deficiency Gastrointestinal •malaborption Drugs •steroids •alcoholism Malignancy •myeloma Rheumatoid arthritis

Question 4

osteoporosis investigations?

Answer 4

Blood and urine tests to exclude secondary causes: FBC, ESR, bone renal and liver profiles •Myeloma screen •TFTs •testosterone in men •25(OH) vit D + PTH •Anti-TTg antibodies Bone density scan

Question 5

osteoporosis treatment?

Answer 5

First line treatments are oral bisphosphonates These agents reduce fracture rates by up to 50% and increase bone density They are osteoclast inhibitors Most patients also require calcium and vitamin D supplements (especially the elderly)

Question 6

what is denosumab?

Answer 6

RANK ligand inhibitor –RANK ligand stimulates osteoclasts –secreted by osteoblasts •Mimics osteoprotegerin (OPG) –natural decoy receptor for RANK ligand •60 mg s/c every 6 months •V effective with 60 - 70% reduction in fractures