Osteoporosis Flashcards
Osteoporosis
Reduction in the strength of bone that leads to increased risk of fractures
World Health Organization (WHO) for Osteoporosis
A bone density that falls 2.5 standard deviations (SD) below the mean for young healthy adults of the same sex (T score of -2.5)
Postmenopausal women who fall b/w -1.0 and -2.5 also have low bone density and are at increased risk of developing osteoporosis
(>50% of fxs among postmenopausal women occur in this group)
Epidemiology for Osteoporosis
Most common bone disease
Osteoporosis causes around 2 million fractures/yr in US
As many as 8 million women and 2 million men have osteoporosis and an additional 18 million have osteopenia (T score -2.5)
Morbidity and indirect mortality rates are very high
Primarily due to complications of the treatment of fractures
Fractures of distal radius increase in frequency before age 50 and plateau by age 60 w/ only a modest age-related increase thereafter
Complications of Osteoporosis
Wrist Fractures
Hip fractures
Associated with a high incidence of DVT and PE (20-50%)
Mortality rate b/w 5-20% during the 1st year after surgery
Vertebral fractures are relatively asymptomatic
Associated w/ a long-term morbidity and a slight increase in mortality rates primarily due to pulmonary disease.
Multiple fractures lead to loss of height, kyphosis and secondary pain and discomfort in the back.
Thoracic fractures can be associated with restrictive lung disease
Primary type of Osteoporosis
Type I: Postmenopausal (rapid bone loss w/in 6 years of menopause, mainly trabecular bone)
Type II: Senile (men and women >75yr of age), slow progression, both cortical and trabecular bone
Secondary type of Osteoporosis
Sex hormone deficiency (hypogonadism, prolactinoma, orchiectomy for tx of prostate cancer) Hormone excess (hyperthyroidism, hyperparathyroidism, corticosteroids) Increased bone resorption/formation ratio: immobilization, space flight, long term heparin, cancers such as MM, lymphoma, breast cancer Multifactorial (renal failure, anorexia, athletic amenorrhea, ETOH use d/o)
Risk Factors of Osteoporosis Non Modifiable
Women (postmenopausal/low estrogen) White race Advanced age Personal hx of fracture as an adult History of fracture in a first degree relative Dementia
Risk Factors of Osteoporosis Potentially Modifiable
Low body weight Current cigarette smoking ETOH abuse Low calcium intake Vitamin D deficiency Inadequate physical activity/immobility
Risk Factors of Osteoporosis Chronic Disease
Rheumatologic and autoimmune d/o
Endocrine: hypogonadal states, anorexia, DM, Cushings syndrome, hyperthyroidism
GI disorders: Celiac, gastric bypass, Crohn’s, malabsorption
Hematology/Oncology: Multiple Myeloma, lymphoma, leukemia
CNS: Epilepsy, Muscular Sclerosis (MS), Dementia, Parkinsons Dz, poor eyesight
Risk Factors of Osteoporosis Medications
Glucocorticoids (most common), anticonvulsants, immunosuppressants(cyclosporine), cytotoxic drugs, Aromatase inhibitors, long term Heparin, Lithium, hormonal therapies, long term PPIs, high dose inhaled steroids in elderly
Pathophysiology for Normal Growth
Skeleton increases in size by linear growth and by apposition of new bone tissue on the outer surface of the cortex called modeling (allows the long bones to adapt and shape to the stresses placed on them).
During puberty, there is increased sex hormone production that is required for skeletal maturation
In young adults resorbed bone is replaced by an equal amount of new bone (bone mass remains constant after peak bone mass is achieved in adulthood)- equal balance
Pathophysiology for Adults
Bone remodeling (2 primary functions) Repair microdamage w/in the skeleton to maintain skeletal strength To supply calcium from the skeleton to maintain normal serum calcium **Regulated by: estrogen, androgens, vitamin D, Parathyroid hormone (PTH) as well as numerous growth factors
At age 30-45yr: Resorption exceeds formation
Exaggerated in women after menopause
Excessive bone loss can occur if there is an increase in osteoclastic activity and/or a decrease in osteoblastic activity
Signs and Symptoms for Osteoporosis
Usually asymptomatic unless the patient sustains a fracture
Gradual height loss
Increased kyphosis of thoracic spine (Dowager hump) with a secondary protuberant abdomen
Pain (bone pain or deformities may result from fractures)
Diagnosis for Osteoporosis
Made clinically in the setting of a fragility fracture regardless of T-score
In postmenopausal women and men>50 w/ no fragility fracture diagnosed by bone density testing
Labs for Osteoporosis
Primarily used to rule out secondary causes: CBC (anemia, Multiple Myeloma) Calcium elevated hyperparathyroidism low Vitamin D def or GI malabsorption Phosphorus (elevated in renal failure) Vitamin D level (goal is >30ng/mL) Albumin (nutrition status) Alkaline Phosphatase Serum protein electrophoresis- MM Creatinine (kidney function) TSH (hyperthyroidism) PTH Elevated hyperparathyroidism Low suggests malignancy
24-h urinary calcium excretion
300mg/24h indicates hypercalciuria
In men total testosterone and liver transaminases