Biochemistry Flashcards
What is osteoporosis
Quantitative defect of bone, reduced bone mineral density, increasing porosity, fragility
Define osteopenia and osteoporosis
Osteopenia: 1 - 2.5 SD
Osteoporosis: greater than -2.5SD
Type 1 osteporosis
Post-menopausal
Smoking, alcohol, poor diet, lack of exercise
Fractures (colles and vert insuff)
Type 2 osteoporosis
Old age
Chronic disease, low vit D, in activity
Fractures (femoral neck, vert)
Serum Ca and phosphate in osteoporosis
Normal
Treatment of osteoporosis
Exercise before 30, diet, sun Ca and vit D Bisphosphonates (alendronate, risedronate) MAB (desunomab) Strontium HRT
What do bisphosphonates do?
Decrease Oc resorption
What does strontium do?
Increases Obs
Reduces Ocs
What does denusomab do?
Reduces Oc activity
What is osteomalacia?
Qualitative defect of bone, abnormal softening due to deficient mineralisation of osteoid secondary to inadequate Ca and phosphate
Cause of osteomalacia
Insufficient absorption of Ca from intestine
Lack of dietary Ca
Resistance or lack of Vit D
Phosphate defiicency (renal losses, tubular acidosis, alcohol)
Symptosm of osteomalacia
Bone pain
Deformities
Pathological fractures
Hypocalcaemia = paraesthesia, cramps, irritability, brittle nails, pseudofractures
Bone biochem in osteomalacia
Low Ca and phosphate
High ALP
Treatment of osteomalacia
Vit D therapy
Ca and phosphate
Hyperparathyroidism
Overactivty of PT glands = high Ca
Fragility fractures, lytic lesions (Brown tumours)
Primary hyperparathyroidism
Benign adenoma, hyperplasia
Hypercalcaemia = stones, bones, moans, groans
High PTH, high Ca, normal/low phosphate
Secondary hyperparathyroidism
Overproduction of PTH due to hypocalcaemia
Caused by CKD or vit D deficiency
Tertiary hyperparathyroidism
Chronic secondary hyperparathyroidism long standing (CKD) = adenoma = produces PTH even if Ca corrected
Treatment of hyperparathyroidism
Skeletal stabilisation
Remove PT glands
Vit D supplements
IV fluids, bisphosphonate, calcitonin
Renal dystrophy
Bone changes in response to CKD
Reduced phosphate excretion and inactive Vit D = secondary hyperparathyroidism = osteomalacia, sclerosis and calcification of soft tissue
Paget’s disease
Chronic disorder resulting in thick, brittle, misshapen bones
Increased Ocs = increased turnover
Obs = correct resorption
Pelvis, femur, skull, tibia, ear ossicles = deafness
Symptoms of Paget’s
Arthritis Pathologic fractures Deformities Pain HF Raised ALP, Ca and phosphate normal
Treatment of Paget’s
Bisphosphonates (inhibit Ocs)
Calcitonin (if lytic)
Joint replacement
