Osteoporosis Flashcards
Thyroid Gland and Osteoporosis
Thyroid gland can stimulate or inhibit osteoclast activity
Hyperthyroidism/overtreatment of hypothyroidism stimulates an increase in osteoclast activity
Increased plasma calcium causes thyroid to release calcitonin - Inhibits osteoclast activity and stimulates osteoblast activity
Factors associated w/ osteoporosis
OSTEOPOROSIS
Low calcium intake
Seizure meds
Thin builds
ETOH
Hypogonadism
Previous fracture
Thyroid excess
Race -white, asian
Other relatives w/ FHx
Steroids
Inactivity
Smoking
T score w/ Osteoporosis
Bone mineral density compared to what is normally expected in young healthy adult @ peak BMD based on gender
<-2.5 indicates osteoporosis
<-2.5 + fragility fracture indicates severe osteoporosis
Z score w/ Osteoporosis
Used in premenopausal women, <50 yo men, children
<-2.0 is below expected range
Cannot make osteoporosis diagnosis on BMD alone
Quantitative Calcaneal Ultrasonography
Effective predictor of femoral neck, hip, and spine fracture without exposure to radiation
Used to screen, cannot be used to diagnose alone
Vertebral Xray Imaging Indications
Can be done if bone density testing not available, typically only done if pt is symptomatic
Consider with T-score -1.5
Women 65-69
Men 75-79
New fracture, loss of height, new back pain or postural change
Labs to screen for osteoporosis
CBC
CMP
Serum magnesium
TSH
25-OH Vitamin D
PTH
Testosterone
24 hour urine Calcium
Calcium Supplementation
1200 mg daily
SE: nephrolithiasis, dyspepsia, constipation
Interferes with iron and thyroid hormone absorption
Calcium citrate is better than carbonate with concomitant use of H2 blockers and PPIs; also less likely to cause kidney stones
Vitamin D Supplemention
800 IU Vitamin D3
May need more if initial levels are low
SE: Excessive levels cause hypercalcemia, hypercalciuria, kidney stones
Bisphosphonates
Fosamax
Actonel
Reclast
Boniva
-dronate
Zoledronic acid
Bisphosphonates Use
MOA: inhibit bone reabsorption by decreasing the number and function of osteoclasts
First line for osteoporosis beyond supplementation
Poor oral absorption, cleared renally - GFR must be >30-35 ml/min; correct calcium and vitamin D deficiency before use
SE: Esophagus erosion, osteonecrosis of jaw, hypocalcemia, MSK pain, ocular pain or vision changes, atypical fractures
Assess if need continues after 5 years therapy
-May DC w/ T score >-2.5
Raloxifene (Evista)
Estrogen Agonist/Antagonist
Decrease risk of vertebral fracture, indicated with risk of invasive breast cancer in postmenopausal women w/ osteoporosis
Less effective than estrogen and bisphosphonates
SE: DVT, hot flashes, endometrial cancer
Miacalcin or Fortical
Calcitonin - active 25OH Vitamin D
Approved for use in osteoporotic women <5yrs out from menopause
Decreases risk of vertebral fractures with history of vertebral fractures - not without history
Antagonize PTH effects; CI w/ salmon allergy
SE: epistaxis, rhinitis, allergic reaction
Prempro
Hormone Replacement Therapy
Only use when all other non-estrogen replacement therapies fail
Decrease risk of vertebral, hip, and osteoporotic fractures
Increased risk MI, CVA, invasive breast cancer, PE, DVT
Teriparatide (Forteo)
Parathyroid hormone
Stimulates bone formation - for severe osteoporosis when other treatments have failed
Maximum treatment duration for 24 months - monitor for serum calcium alterations
SE: Leg cramps, nausea, dizziness, increased risk osteosarcoma
