(3) Osteoporosis Flashcards
What is the radiographic finding of osteoporosis?
osteopenia
With osteoporosis, bone has ____ quality, and ____ quantity.
- normal quality
- reduced quantity (^porous trabecular bone)
With osteomalacia, bone has ____ quality, and ____ quantity.
- reduced quality
- normal/reduced quantity
What are the 3 categories of osteoporosis?
- generalized
- regional
- localized
What category of osteoporosis involves the majority of the skeleton?
generalized
What category of osteoporosis involves most of a limb?
regional
(region or segment of body affected)
What category of osteoporosis is periarticular osteoporosis?
localized
(focal area of bone loss)
What category of osteoporosis is permeative/motheaten osteolysis?
localized
(focal area of bone loss)
What is the most common cause of generalized osteoporosis?
post-menopausal/senile
What patient are we most concerned about never hitting peak bone density?
female athlete triad
(amenorrhea –> less hormones, less protective)
What is another name for post-menopausal/senile osteoporosis?
senescent osteoporosis
What demographic is affected by post-menopausal/senile osteoporosis?
- F>M (4:1 in 5th & 6th decades)
- males catch-up to bone loss in 7th & 8th decades
How does bone density change after 35 years of age?
1% cortical and 2% medullary bone loss per year
What is the rate of bone loss per year at menopause?
3-6%
What are the clinical and lab findings of post-menopausal/senile osteoporosis?
- painless until Fx or deformity
- normal labs
What is the most common skeletal location of post-menopausal/senile osteoporosis?
axial skeleton –> extremities
What locations of traumatic/pathologic fractures are considered life-threatening in patients with post-menopausal/senile osteoporosis?
- thoracolumbar spine
- hip
What postural finding is associated with post-menopausal/senile osteoporosis?
Dowager’s hump
(microFx’s create hyperkyphosis)
What are the common locations of traumatic/pathologic fractures in patients with post-menopausal/senile osteoporosis?
- T/L spine
- hip
- distal radius
- proximal humerus
What are the common location of insufficiency fractures in patients with post-menopausal/senile osteoporosis?
- T/L spine
- sacrum
What is the imaging modality of choice for evaluating bone density?
densitometry (DEXA)
(radiographs are insensitive to early density changes; no zone of impaction)
What are the radiographic findings of osteopenia?
- cortical thinning (pencil-thin)
- altered trabecular pattern (body of vertebra same shade as ST; pseudo-hemangiomatous appearance)
- fractures (fish/biconcave vertebrae, Schmorl nodes)
- deformities (^kyphosis)
How would you differentiate osteopenia in the spine versus a hemangioma?
osteopenia is seen affecting multiple levels as opposed to just 1 segment
Describe the changes in trabecular pattern that occur with osteopenia
- early resorption of non-weight bearing trabeculae (horizontal; ^Ward’s triangle)
- late resorption of weight bearing trabeculae (vertical)
How is Dual Energy X-ray Absorptiometry used?
uses low dose x-rays to quantify bone mass (severity of osteoporosis or osteopenia)
What are the 2 types of DEXA scans and what body regions are they used for?
- central: spine, hips
- peripheral: radius, calcaneus, finger
What 2 readings are obtained from a DEXA scan?
- T-score
- Z-score
What is the T-score on a DEXA scan?
bone density compared to 18-25y/o of same race & gender; gives risk of Fx
What is the Z-score on a DEXA scan?
bone density compared to other pts of same age, race, gender
What population is the Z-score useful for?
pre-menopausal female athlete triad
What T-score readings are considered normal?
+1 to -1
What T-score readings are considered osteopenia?
-1 to -2.5
What T-score readings are considered osteoporosis?
-2.5 or less
What T-score readings are considered severe osteoporosis?
-2.5 or less with a Hx of fragility Fx
What does T-score of -2 indicate about fracture risk?
4x more likely to Fx
(2^2)
What does T-score of -3 indicate about fracture risk?
8x more likely to Fx
(2^3)
What does T-score of -4 indicate about fracture risk?
16x more likely to Fx
(2^4)
What are 3 causes of regional osteoporosis?
- disuse osteoporosis
- complex regional pain syndrome (CRPS)
- transient regional osteoporosis (of the hip)
When determining differentials for regional osteoporosis, what is the first question to ask yourself?
is it in the hip?
If regional osteoporosis is affecting the hip, what is the likely diagnosis?
transient regional osteoporosis of the hip (TROH)
If regional osteoporosis is not affecting the hip, what is the next question to ask yourself?
is there an old Fx?
If regional osteoporosis is not affecting the hip, and there is evidence of an old fracture, what is the next question to ask?
is their pain increasing or decreasing?
If regional osteoporosis is not affecting the hip, there is evidence of an old fracture, and no pain, what is the likely diagnosis?
disuse osteoporosis
If regional osteoporosis is not affecting the hip, there is evidence of an old fracture, and increasing pain, what is the likely diagnosis?
CRPS
OR
Disuse
If regional osteoporosis is not affecting the hip, and there is no evidence of an old fracture, what is the likely diagnosis?
CRPS
What are the 3 patterns of regional osteoporosis on imaging?
- mottled (irregular) radiolucency (simulates permeative/motheaten destruction)
- band-like metaphyseal or epiphyseal radiolucency
- generalized osteoporosis
What is the most common cause of regional osteoporosis?
disuse osteoporosis
What can cause disuse osteoporosis?
immobilization:
- Fx in cast
- wheelchair bound
- paralysis
What are the radiographic findings of disuse osteoporosis?
- can appear like permeative lytic
- appears 7-10 days after immobilization(disuse occurs in extremities)
- peak density loss by 2-3 months (8-12wks)
What percent of bone density loss must occur after immobilization to be visible radiographically?
30%
What are other names for complex regional pain syndrome?
- reflex sympathetic dystrophy syndrome
- post-traumatic osteoporosis
- sudeck’s atrophy
- causalgia
- shoulder-hand syndrome
What is the definitive diagnostic test for regional osteoporosis due to complex regional pain syndrome?
3 phase bone scan
If you determine your patient has CRPS, what is your next step?
refer to neurology
What is the clinical presentation of CRPS?
- unexplained severe neurologic pain
- surface changes (hair loss on forearms, sweating/anhidrosis)
What is the most common location of transient regional osteoporosis?
hip (femoral head/neck)
What is another name for transient regional osteoporosis of the hip?
transient bone marrow edema of the hip
What demographic is primarily affected by transient regional osteoporosis of the hip?
- M>F
- 20-40yrs
What is the clinical presentation of transient regional osteoporosis of the hip?
- sudden onset
- pain (not reproduceable)
- antalgia & limp
- self-limiting (full recover in 3-12mo)
What are the early imaging features of transient regional osteoporosis of the hip?
- X-ray = normal
- MRI = marrow edema
What are the late imaging features of transient regional osteoporosis of the hip?
- X-ray = regional osteopenia
- MRI = marrow edema
