Osteoporosis

OSTEOPOROSISDAVIN PANNAAUSTEN

WHAT IS OSTEOPOROSIS?

Osteoporosis which means porous bone is a generalized disease of bone characterized by a combination of decreased osteoblastic formation of matrix and increased osteoclastic resorption of bone, with a resultant decrease in the total amount of bone in the skeleton

ETIOLOGY• Endocrine diseases• Hypogonadism• Hypercortisonism• hyperthyroidism

• Disuse• Post-menopausal state• Senility• Alcohol abuse

RISK FACTORS• Gender (female>male) 25% vs 12.5%• Amenorrhea • Insufficient calcium in diet• Eating disorders such as anorexia nervosa• Smoking• Excessive consumption of caffeine or alcohol• Inadequate physical exercise• Race (black Africans somehow less prone to age related

fracture, whites and Asians more at risk)

PATHOLOGY• Involves increased bone resorption• Also involves a decrease in bone formation• Both are surface phenomena• Affects trabecular bone more than cortical bone due to the

larger surface area• Thus, osteoporosis is most severe in vertebral bodies and

metaphyses of long bones• Cortical bone eventually becomes thin and porous as well

PATHOLOGY• This reduction in bone mass causes the bones to become

fragile, instead of becoming “soft” as in osteomalacia • As such, even modest stress or low energy trauma can cause

fractures: pathological fractures

X-RAY IMAGING• Generalized rarefaction of all bones, but most marked in

cancellous bone• Thin cortices• Evidence of deformity particularly in vertebral bodies• In severe cases a fracture or collapse of the spinal bones may

be seen

RAREFACTION OF BONE

BONE MINERAL DENSITOMETRY (BMD)

• An imaging technique used to measure bone density • Expressed in gram per unit area• Method of choice is the dual energy x-ray absorptionetry

(DXA)

INDICATIONS FOR BMD• All women > 65 years• All postmenopausal women< 65 years with other risk factors• Men with testosterone deficiency• Post-oophorectomy• X-ray features of osteopenia• Patients with hyperparathyroidism, hyperthyroidism, renal

insufficiency, or rheumatoid arthritis• Patients on long term glucocorticoids, thyroid hormone

replacement, thiazide diuretics• Dietary deficiencies• Checking treatment results

LAB TESTS• Serum calcium and phosphate• Serum bone alkaline phoisphatase• Osteocalcin• Parathyroid hormone activity• Vitamin D activity• Urinary calcium and phosphate• Glucocorticoid levels• Thyroid hormone levels• Estrogen / testosterone levels

PRINCIPLES OF MANAGEMENT• Osteoporosis cannot be reversed• Therefore treatment is given to slow down or stop the

progression• Any fracture must be managed properly as and when they

happen• Increase mobility to prevent disuse osteoporosis• Avoid prolonged immobilization

MEDICATION• Vitamin D• Calcium• Anti-resorptive medication (biphosphonates, calcitonin)• Hormone replacement therapy