Metabolic Bone Disease Flashcards
(97 cards)
1
Q
If there are increased calcium levels the x gland releases x?
A
the thyroid gland releases calcitonin
2
Q
When calcitonin is released what happens?
A
osteoclast activity is inhibited and calcium reabsorption in the kidneys decreases, so calcium level in the blood decreases
3
Q
If there is decreased calcium levels the x gland releases x?
A
parathyroid glands release PTH
4
Q
When PTH is released what happens?
A
osteoclasts release calcium from bone, calcium is reabsorbed from urine by the kidneys, calcium absorption in the small intestine via vitamin D synthesis; so calcium level in the blood increases
5
Q
What is bone remodeling?
A
orderly process of bone resorption and subsequent bone formation AKA “coupling”
6
Q
90-95% of bone cells are?
A
osteocytes
7
Q
What do osteocytes do?
A
actively secrete and calcifies bone matrix material; regulate bone resorption and formation
8
Q
Osteocyte activity produces
A
active release of cytokines needed for osteoclast development
9
Q
What receptors and inhibitors regulate and control osteoclast production?
A
RANKL and OPG
10
Q
What is bone mineral density?
A
amount of bone acquired during adolescence and young adulthood
11
Q
Factors impacting the remodeling process
A
hormones, physical activity, nutrition, genetic influence
12
Q
When is peak bone mass of the proximal femur?
A
18-20
13
Q
When is peak bone mass of the spine?
A
25-30
14
Q
What is osteoporosis?
A
skeletal disorder defined by decreased bone strength and increased fracture risk
15
Q
What’s the most common metabolic bone disease?
A
osteoporosis
16
Q
What fractures are associated with osteoporosis?
A
fragility fractures
17
Q
Primary causes of bone loss
A
aging, estrogen status (age of menopause), nutrition (Ca/vitamin D), peak bone mass, genetics, level of physical activity
18
Q
Who is more affected by osteoporosis?
A
women
19
Q
What’s considered juvenile osteoporosis?
A
8-14 y/o
20
Q
Stage I osteoporosis impacts?
A
post-menopausal women (ages 51-75)
21
Q
Stage I osteoporosis is?
A
accelerated trabecular bone loss
22
Q
Common fractures with stage I osteoporosis?
A
vertebral body and distal forearm fractures
23
Q
Stage II osteoporosis impacts?
A
men and women aged >70
24
Q
Stage II osteoporosis is?
A
both trabecular and cortical bone loss
25
Common fractures with stage II osteoporosis?
wrist, vertebra, hip
26
Secondary osteoporosis impacts who more?
men
27
What's secondary osteoporosis?
underlying factor has been identified like environmental factor or disease state
28
Environmental factors of osteoporosis?
poor nutrition, calcium/vitamin D deficiency, physical inactivity, decreased sun exposure, medications, tobacco use, alcohol use (>3 drinks/day), traumatic injury (NWB/bed ridden), high caffeine intake
29
Medications associated with osteporosis
PPI, chronic corticosteroid use >3 months, aromatase inhibitors, anticonvulsants, anticoagulants, SSRI, excessive thyroxine, chemotherapy
30
Secondary causes of bone loss
hypogonadism, Cushing's, hyperparathyroidism, hyperthyroidism, DM, hyperprolactinemia, vitamin D deficiency, alcohol, malabsorption, chronic liver disease, primary biliary cirrhosis, gastrectomy, multiple myeloma, OI, Marfan, RA, immobilization
31
Osteoporosis is most common at age?
>70
32
Osteoporosis is common at what age in post-menopausal women?
50-70
33
Wrist fractures due to osteoporosis are common at what age?
50-59
34
Vertebral fractures due to osteoporosis are common at what age?
seventh decade
35
Hip fractures due to osteoporosis are common at what age?
50+; most common in eighth decade
36
Non-modifiable osteoporosis risk factors
personal history of fracture as adult; history of fracture in primary relative, white race, advance age (>50), female, dementia, poor health, amenorrhea
37
Modifiable risk factors for osteoporosis
current cigarette smoking, low body weight (<127 lbs/BMI), estrogen deficiency, low lifetime calcium intake, alcoholism, recurrent falls, inadequate physical activity, poor health
38
Osteoporosis symptoms
silent with no signs or symptoms
39
Major osteoporotic fracture sites
spine T11-L2 (don't even have to fall), proximal femur, distal forearm, proximal humerus
40
Careful evaluation of what for osteoporosis?
measure height loss (>4 cm since young adult maximum height suggest prior vertebral fractures or scoliosis); BMI; Kyphosis; spinal TTP and percussion
41
FRAX takes into account what?
demographics, previous fracture, parent fractured hip, current smoking status, glucocorticoids, RA, secondary osteoporosis, alcohol (>3 units/day), femoral neck BMD from DEXA
42
Osteoporosis work up labs
serum BMP (evaluate renal/hepatic function), parathyroid levels, CBC (nutritional status and myeloma), thyroid function tests, 25-hydroxyvitamin D-25(OH)D, serum calcium levels, consider 24 hour urine calcium, testosterone levels in men
43
What are all the labs for osteoporosis really looking at?
secondary causes of bone loss
44
What do we look for in a 24 hour urine for osteoporosis?
calcium (excess skeletal loss, vitamin D deficiency, malabsorption), creatinine, sodium, and free cortisol (Cushings)
45
What are the biochemical markers of bone remodeling?
bone-specific alkaline phosphatase (BSAP) and Osteocalcin (OC) in serum; N-Telopeptide cross-links (NTX) and C-telopeptides (CTX) in urine
46
What do we think of biochemical markers of bone remodeling?
controversial
47
Imaging for osteoporosis?
x-ray symptomatic area; DEXA to measure BMD
48
What's the gold standard for screening and monitoring changes for osteoporosis?
DEXA
49
What sites should you evaluate with DEXA?
hip, spine, wrist
50
Dexa T-score
value compared to that of control subjects at peak BMD
51
Dexa z-scores
value compared to that of patient matched for age and sex
52
DEXA indications
women 65 years and older and men 70 years and older; younger postmenopausal women; women in menopausal transition with clinical RF for fracture; men 50-69 y/o clinical RF for fracture; adults with conditions or medications associated with secondary osteoporosis
53
A T-score within x SD of healthy young adult is normal bone density.
1
54
A T-score between x and x means a low bone density or osteopenia.
-1.0 and -2.5 SD
55
A T-score of x is a diagnosis of osteoporosis.
-2.5 SD or below
56
T-score of x + a fragility fracture Severe (established osteoporosis)
-2.5 SD or below + a fragility fracture
57
The lower a person’s T-score, the lower
the bone density:
58
A Z-score above x is normal
-2.0
59
NOF does not recommend routine bone density testing in these age groups.
children, teens, women still having periods and younger men, premenopausal women with no RF, men <70 without RF; women <65 w/o RF
60
DEXA limitations
doesn't distinguish between low bone density vs. undermineralized bone matrix (osteomalacia); BMD varies between regions (spinal vs. distal radius)
61
Repeat testing for women with normal BD or mild osteopenia
up to 10-15 years
62
Repeat testing for women with moderate osteopenia
3-5 years
63
Repeat testing for women with advanced osteopenia
usually annually
64
Repeat testing for women undergoing treatment for osteoporosis
annual BMD
65
People larger than x pounds DEXA reads may not be as accurate
300 pounds
66
What can be done to analyze bone density in those larger than 300 lbs
peripheral bone density test at wrist (radius) and heel
67
Bone density screenings other than DEXA
QCT (quantitative CT of spine), pQCT (wrist and tibia), finger DXA, ultrasound of calcaneus or wrist
68
First line treatment of osteoporosis
supplemental calcium; women 19-50 and men 19-70 = 1000 mg; women >50 and men >70 = 1200 mg.... supplemental vitamin D: anyone 18-70 = 600 IU/Day, anyone >71 = 800 IU
69
Which gender is more likely to die within a year after breaking a hip
men
70
Why are men less likely to experience osteoporosis?
Androgens do not wane abruptly, like menopause; Slow decline in testosterone and estrogen levels
71
Men's risk of fracture increases after
70
72
Osteoporosis risk factors in men
Age >70, low BMI (<20-25), weight loss >10% body weight, physical inactivity, androgen deprivation therapy (treatment of prostate CA), previous fragility fracture, spinal cord injury
73
What's osteomalacia?
softening of the bone; decreased mineralization between calcified bone and osteoid
74
What's Rickets?
Defective mineralization of cartilage in the epiphyseal growth plates in children
75
Etiology of osteomalacia?
vitamin D deficiency...hypophosphatemia....Low Vit D/calcitriol levels= decreased Ca+ absorption= hyperparathyroidism= increased urinary phosphate excretion/wasting; chronic renal or liver disease; mineralization inhibitors (aluminum, fluoride)
76
RF for osteomalacia
living in cold climates (little sun exposure); insufficient dietary ca and vitamin D; malabsorption disorders; hereditary vitamin d deficiency
77
CM of osteomalacia
asymptomatic, bone pain/tenderness, deformity, muscle weakness, fracture, antalgic gait/difficulty ambulating, muscle spasms, numbness/tingling, + chvostek's sign
78
what sign is associated with osteomalacia?
Chvostek's sign: tap on facial nerve, see twitching of facial muscles, hyperexcitability
79
Work up for osteomalacia?
CMP, LFTs, phosphate, calcium, alkaline phosphatase, PTH (start to rise with 25(OH)D ais around 31 ng/ml); 25-hydroxyvitamin D (<30 = insufficient; <15-20 = deficient), 1,25 dihydroxyvitamin D
80
Imaging for osteomalacia?
x-ray, bone biopsy (maybe)
81
Osteomalacia treatment
Vitamin D replacement
82
Target vitamin D serum in osteomalacia
>30 ng/ml
83
age 0-1 osteomalacia treatment
Initial: 2000 IU q day vs 50,000 IU q week x 6 weeks
Maintenance: 400-1000 IU q day
84
1-18 osteomalacia treatment
Initial: 2000 IU q day vs 50,000 IU q week x 6 weeks
Maintenance: 600-1000 IU q day
85
>18 osteomalacia treatment
initial: 6,000 IU q day vs 50,000 IU q week x 8 weeks
Maintenance: 1500-2000 IU q day
86
what if a person is getting osteomalacia treatment and has malabsorption?
2-3 x higher dose
87
What's paget disease?
Localized bone remodeling disorder; Excessive resorption, then increased bone formation; Disorganized bony structure- weaker and more susceptible to fracture
88
Etiology of Paget Disease
genetic predisposition; maybe viral, autoimmune, connective tissue disorder, vascular disorder
89
phases of paget disease
1) lytic phase: osteoclast activity-resorption; increase in number, size, and number of nuclei 2) mixed phase--osteoclast and osteoblast activity; bone resorption and formation leading to disorganized bone formation 3) sclerotic phase--disorganized bone formation becomes vascular, fibrous connective tissue
90
Paget affects which bones?
PELVIS, lumbar spine, thoracic spine, femur, sacrum, skull, tibia, humerus
91
Who is more affected by Paget men or women?
men
92
CM of Paget disease
asymptomatic, bone pain is location specific, if skull (hearing loss, HA, tinnitus, increased hat size, cranial nerve palsies), pathologic fractures
93
PE of Paget disease
deformities (bowing, kyphosis), decreased ROM, localized TTP, conductive vs. sensorineural hearing loss, abnormal gait
94
Complications of paget disease
fractures, neoplasms (rare, but osteosacroma from fibrotic tissue), spinal cord compression, cerebellar compression, cranial nerve palsies, degenerative joint disease, left ventricular hypertrophy, calcific aortic stenosis
95
Imaging of paget
plain films, possibly bone scan
96
Labs for paget
alkaline phosphatase (bone specific), [calcium, vitamin D, phosphate] = normal, urinary markers (hydroxyproline, deoxypyridinoline, c-telopeptide
97
Treatment of paget
Bisphosponates ->
Zoledronate acid (Reclast) 5 mg IV
Alendronate (Fosamax) 40 mg x 6 months
Risedronate (Actonel) 30 mg q daily x 2 months
