OSTEOPOROSIS

06/25/12 José L. González, PGY3

Definition

Reduction in bone strength increase risk of fx

T-score: < -2.5 SDs T-score: 30 yo, matched for sex and race

Osteopenia: <-1 to 2.5 SDs

Epidemiology

>10 million 8 million women & 2 million men

Most fractures occur in women w/ osteopenia

Rate of colles fx increases initially, later hip May be due to the way we fall

Vertebral > Hip > Colles

Risk Factors

Age, female sex, cigarette smoking, prior fxs, low body weight, excess etoh

Meds: glucocorticoids, cyclosporine, heparin, levothyroxine, anticonvulsants

Diseases Vision Dementia Chronic inflammatory diseases

RA Crohns

Bone Remodeling

Bone mass is 50-80% heritable Peak skeletal mass early adulthood.

Constant mass 30-45 yoa, then increased resorption

Estrogens, androgens, vitamin D, PTH 2 functions

Repair microdamage of the skeleton Maintain [Ca2+] serum

Risk Factors: Parathyroid Hormone Kidneys

1. ↑ hydroxylation 1,25OH vit D 2. decreased Ca2+ loss

Small Intestine ↑Ca2+ absorbtion

Bone Release of Ca2+

Risk Factors: vitamin D / Calcium Calcium: RDI 1000 – 1200 Vitamin D: RDI 800-1000 units daily

RFs for low vit D: High latitude Low intake Chronic liver or renal disease

Estrogen Physical Activity

↓risk in rural communities

Diagnosis

US, CT scan, single energy absorptiometry, DXA

DXA Lumbar and hip m.c. used Z-score: age matched T-score: 30 yo, race and sex matched

Who to test:

All women > 65 yoa Estrogen deficient women @ risk Vertebral abnormality of x-ray

suggestive Primary hyper parathyroidism Steroids > 7.5mg x 3 months Monitoring response to meds Repeat @ 2 year intervals

Who to treat:

T-score < -2.5 SDs Post-menopausal women w/ RFs

RFs: age, prior fx, family hx, low weight, smoking, RA, etoh

FRAX calculator

Treatment: SERMs, PTH, Calcitonin Raloxifene:

tx & pv of ER+ breast ca Tx & pv of osteoporosis

PTH: in small amounts Calcitonin: (intranasal)

Hormone produced by thyroid decreases osteoclast activity Decreases vert. fxs only

Treatment: Estrogens

Estrogens (in the form of combined OCPs) Decrease fracture risk by 50% Increase risk of MI by 29% Increase stroke risk by 40% dementia 2x Increase risk of breast ca by 26% Decrease risk of colon ca by 37% Increase risk of VTE by 100%

10,000 patients: prevents (5 hip, 6 colles & 44 clinical fxs) leads to (8 breast cas, 8 MIs, 18 VTEs)

Treatment: Bisphosphonates Alendronate:

5mg x 2 yrs, 10mg x 9 months 90% ↓vert. fx, 50% ↓hip fx

70mg PO dose once weekly Risedronate:

use in steroid-induced OP Ibandronate Zolendronic Acid:

70mg IV q yearly for hyperCa2+

Bisphosphonates: Side Effects Osteonecrosis of the jaw hypocalcemia GI side effects

Esophagitis, ulceration Contraindicated in strictured esophagus Drink w/ full glass H20 and remain upright x

30min

Sources:

Harrison’s Principles of Internal Medicine. 18th ed. New York, NY: McGraw-Hill; 2005:946.