ENDO-Osteo Flashcards
What is the relationship between bone mass and age?
Decreases with age 3r-4th decade.
existing bone cells are reabsorbed by the body faster than new bone is made.
What is the major risk with Osteoporosis? What are the most common type
50% vertebral fractures - asymptomatic, Height loss, kyphosis, back pain
25% hip fractures -Falls onto the hip; Risk for DVT, PE; high mortality
25% Colles’ fractures -FOOSH
What are the Nonmodifiable risk factors?
1] h/o fracture as adult-IDNP 2] H/o fracture in 1st degree relative, 3] Female sex, 4] Advanced age, 5] Caucasian/Asian race, 6] Family history-IDNP 7] Dementia
What are the modifiable risk factors?
1] Cigarette smoking- inhib osteoblast, dec ca abosrbtion 2] Low body weight 127 lbs) -IDNP 3] Estrogen deficiency, 4] Low calcium intake, 5] Chronic steroid use, 6] Alcoholism, 7 7] Impaired eyesight, 8] Recurrent falls, 9] Inadequate physical activity, 10] Poor health / frailty
What are the protective factors for osteoporesis?
1] Higher BMI,
2] Black race,
3] Estrogen or diuretic therapy (thiazides),
4] Exercise (start as a child!)
Decribe the benefit of (thiazides)
decrease calcium excretion by the kidney.
associated with higher bone mineral density
reduce the risk of hip fracture.
uncertain -decrease PTH-stimulated bone resorption reduction bone turn-over rate.
What is the pathogenesis of osteoporesis?
Mismatch between bone resorption and bone formation;
What are natural causes of osteoporesis?
1] Age-related bone loss: low loss of cortical and trabecular bone
2] Post-menopausal: Rapid loss of trabecular bone
What is the genetic component of osteoporesis?
Genes involving Vitamin D synthesis,
estrogen receptors,
bone forming proteins
What are the usual cause of high turnover osteoporesis
1] Estrogen deficiency (PMP women)
2] Hyperparathyroidism,
3] Hyperthyroidism,
4] Hypogonadism,
5] Cyclosporine, Heparin
What are the usual cause of low turnover osteoporesis?
1] Liver disease,
2] Age 50 years
What medicatins cause Increased bone resorption and decreased bone formation?
Glucocorticoids
How is Water a function of bone remodeling?
1] Repair microdamage within the skeleton (maintain skeletal strength),
2] Supply calcium from skeleton to body
What regulates bone remodeling?
circulating hormones: estrogens, androgens, vitamin D, parathyroid hormone
IGF-1, ILs, prostaglandins, TNF, cytokines
What is end result of bone remodel? what happens to as you age?
resorbed bone is replaced by an equal amount of new bone tissue
become imbalanced
→ resorption exceeds formation → osteopenia
What is Rapid bone loss, Loss of horizontal connections is seen in osteoporotic bone?
Trabecular bone loss
Osteoclasts penetrate trabeculae leaving no template for new bone formation;
Cortical- inc remodeling l/t porous bones
what does lack of estrogen do to cause the imbalance?
1] Activation of new bone remodeling sites,
2] INC imblance between bone formation and resorption
1] INC osteoclast activity ,
2] INC rate of osteoblast apoptosis,
3] Affects trabecular bone earliest
How does Inadequate calcium intake (diet, malabsorption) affect us?
Secondary hyperparathyroidism - Increased rate of bone remodeling to maintain adequate serum calcium,
Increased GI absorption of calcium
Decreased renal calcium excretion
What is the most common nutritional deficiency worldwide?
Vitamin D Deficiency
asymptomatic, most underdiagnosed medical condition, usually noticed on lab test
Describe what Vitamin D Deficiency causes
secondary hyperparathyroidism-PTH stimulated leads to hypocalcemia, rickets, osteomalacia, osteoporosis
what are the risk factors for Vitamin D Deficiency?
sun avoidance/use of sunscreen, poor nutrition, malabsorption, elderly, chronic liver or renal disease, people living in northern latitudes
What is the function of vitamin D?
1] calcitriol and its effects on calcium and phosphate homeostasis,
2] increase in the serum calcium and phosphate concentrations
Child presents with radiographic evidence of decreased mineralization around the epiphyses and bowing of the LE?
Rickets
only occurs before fusion of the epiphyses
How is osteomalacia related to vitamin D?
following growth plate closure in adults,
incomplete mineralization of the underlying mature bone matrix (osteoid)
rickets can occur with osteomalacia and continue into adulthood
What are the lab values for vitamin D deficency
Serum 25-OH Vitamin D, total: major circulating form Represents endogenous production, diet and supplementation
What are the ranges of Serum 25-OH Vitamin D, total
1] Normal range: 30-100 ng/mL,
2] Deficiency: <20ng/mL,
3] Insufficiency: <30ng/mL
25-OHD3- measure endogenous
25-OHD2- measure of exogenous
D2+D3 = total
Describe the 1-25 dihydroxy vitamin D test
tests biologically active form of vitamin D (hydroxylated in kidney to this form),
not used for overall vitamin D status.
for establishing inherited or acquired disorders of vit D metabolism, a
OR for sarcoidosis, lymphoma, TB, CKD
Describe the initial treatment of vitamin D deficency
1] Cholecalciferol (D3) 1000-2000IU for 8 weeks,
2] Ergocalciferol (D2) 50,000IU QW
QOW for 6-8 weeks
Describe the mainteance treatment of vitamin D deficency
vitamin D level >30
D3 400-1000IU qd to maintain 25-OH
When is Parathyroid hormone level testing indicated
regulates calcium and phosphate homeostasis
abnormal calcium
Describe Primary hyperparathyroidism
parathyroid adenoma causes inappropriate release of
results in hypercalcemia l/t osteopenia/osteoporosis
stimulate calcium resorbtion/breakdown, thus extra in blood
Describe Secondary hyperparathyroidism
commonly due to vitamin D deficiency!!
Kidneys and Gut- unalbe to absorb calcium, thus floating in blood
What if PTH is elevated and vitamin D is low?
1) replace vitamin D,
2) recheck PTH
3) D- levels should normalize
PT c/o Loss of height, kyphosis, mild back pain and had aFalls from standing
Osteoporisis
1] asymptomatic until fractures occur,
2] Loss of height, kyphosis, back pain with vertebral fractures
3] Falls from standing that cause hip or wrist fractures – think about osteoporosis
What are the radiograph features of spinal osteoporosis
wedging of the vertebra anteriorly with vertebral collapse (arrows),
vertebral end-plate irregularity,
demineralization.
What are comorbidities that lead to osteoporosis
1] Hyperthyroidism
2] Hypogonadism
3] Renal disease
4] Cancer (especially multiple myeloma)***,
5] Diabetes-bone turnover is suppressed, do not have low bone mass (increased BMI),
6] GI or liver disease
What is the mnemonic for multiple myeloma
CRAB: C = Calcium (elevated), R = Renal failure, A = Anemia, B = Bone lesions. Bone pain is also common Bence jones proteins
Why lab values of albumin are important?
marker of nutritional status,
necessary for calculating a corrected calcium
ionized calcium so no binding protein interference
Pt has Alkaline phosphate, what can this indicate?
Paget’s, osteomalacia
Pt has Mgphosphate, what can this indicate?
found in bone, low levels can indicate osteomalacia.
PTH regulates phos and calcium
What is Used to estimate bone mineral density?
Bone Densitometry
LOC-for screening and diagnosis of osteoporosis,
based on female Caucasians is used to determine “normal” BMD
List the Bone Densitometry scans
1] Single-Photon Absorptiometry (SPA) - peripheral (radius, calcaneus),
2] Dual-Photon Absorptiometry (DPA) - axial (spine, hip),
3] MC**Dual-Energy Xray Absorptiometry (DXA or DEXA) - spine, hip; low radiation,
4] Quantitative Computed Tomography - Expensive, lots of radiation,
5] Ultrasonography (heel)
What is a comparison of a patient’s BMD to that of a healthy thirty-year-old and same sex?
T score (T-THIRTY) IF -2.0SD, lower than average by two SDs in females
What is used in reference the age-, sex-, and ethnicity-matched population, used in Pre-menopausal women, men <65 yrs, children?
Z- score
IF -0.5 SD, your bone density is less than the norm for people your age by one-half of a standard deviation.
What is the normal BMD, osteopenia BMD, osteoporosis
N-Within T-score -1.0 or higher
Osteopenia-T score between -1.0 and -2.5, osteopenia
OsteoporosisT score -2.5 or lower, osteoporosis
Who should be screened for Osteoporosis
1] All women aged ≥65 years, 2] Post-menopausal women aged ≥60 years if risk factors are present, 3] Men aged 70 and older., 4] Prior fracture, 5] High risk medication use
What is used as a screening tool for Osteoporosis
Hip with DXA
Every 2-3 yrs
Who should be treated for Osteoporosis
1] PMP women and men (> 50 years) with h/o hip or vertebral fracture,
2] Any patient with osteoporosis (T-score ≤-2.5),
3] Any patient with osteopenia (T score -1.0 to -2.5) and an estimated 10-year risk of hip or osteoporosis related fracture
Describe Nonpharmacologic Therapy of Osteoporosis
1] Calcium and Vitamin D intake supp
2] Exercise,
3] Smoking cessation and avoid excessive ETOH intake, 4] Gluten-free diet for celiac disease,
5] Home safety
What is DOC 1st line for prevention and treatment of osteoporsis.
Bisphosphonates
efficacy, favorable cost, and the availability of long-term safety data. DEC Loss at hip
MOA: Inhibits osteoclast activity, reducing bone resorption, turnover; Increase bone mass, decrease fracture risk
ADRs- erosive esophagitis, empty stomach; remain upright for at least 30 minutes.
5-7 years, consider drug holiday,
consistent f/u with DEXA is the best guide
1] Alendronate (Fosamax) 70mg/week,
2] Risedronate (Actonel) 35mg/week, or 150mg/month,
3] Ibandronate (Boniva) 150mg/month,
4] Zoledronic acid (Reclast) 5mg IV q 12 months
WHat Increases bone mineral density, lowers serum LDL levels, decreases risk of vertebral fractures, decreases risk of breast cancer?
Selective Estrogen Receptor Modulators (SERMs) as treatment
Raloxifene (Evista) 60mg/day
MOA- Selectively binds to estrogen receptors, inhibiting bone resorption and turnover
ADRs-venous thromboembolism and hot flashes
What is Indicated for PMP women with high risk of fracture, or failure of other therapy?
Denosumab (Prolia)
Reduces incidence of vertebral, nonvertebral and hip fractures; 60mg SC q 6 months
MOA- RANK-Ligand inhibitor; Reduces bone turnover and resorption by inhibiting osteoclast activity
ADRs-back pain, hypercholesterolemia, hypocalcemia
Which is indicated in symptomatic menopausal women with osteoporosis low risk fracture?
Estrogen/Progestin
Reduce bone turnover, prevent bone loss, increase bone mineral density, reduce fracture risk; May be
ADR-Increased risk of breast cancer, stroke, thromboembolism, and CAD
Which can be used w/ bisphosphonate to maintain bone mass?
Parathyroid- Teriparatide (Forteo) 20 or 40 mcg/d SQ for no longer than 24 months;
High risk pt- caution CA
MOA- Stimulates more bone formation/osteoblast than resorption, but osteoclast via PTH
ADRs- nausea, headache, hypercalcemia, BBW of osteosarcoma- malignant bone tumor
Cuts FX healing, but risk cancer
Which RX is Best in patients with pain from osteoporotic fractures improves bone pain? Not as effective
Calcitonin
Suppresses osteoclast activity;
ADRs- for up to 4 wks, Risk of tachyphylaxis; Recent cancer warning (2012), makes drug less favorable choice
Describe Calcium/Vitamin D Supplements as treatment
Calcium 1000-1200 mg/day in divided doses with food intake;
Vitamin D 800-1000 IU/day;
Best preparations are calcium carbonate + vitamin D bid–tid with food -ALL
How often should BMD be measured after TX?
12-24 months after beginning treatment
What is the indications for decline
1] 4% change in spine or 6% change in hip considered significant,
2] If BMD declines at 2 years, discuss compliance with therapy or consider secondary causes of osteoporosis
