Week 5 Bone Pathology- Witrak Flashcards
Define osteopenia
Generalized decrease in bone mineralization
What is a pathological fracture?
fracture through a diseased bone- usually refers to fracture through tumorous or tumor-like bone
What molecule is required for MINERALIZATION of bone osteoid?
Vit D(OH)2
What do you need for healthy bone?
- Ca, P from diet
- Vit D
- good absorption in gut
- Healthy kidney
- Parathyroid functioning
Why is the parathyroid important?
It is the master gland for Ca regulation and bone metabolism
What is osteoporosis?
A type of osteopenia due to bone atrophy caused by an imbalance of the bone remodeling process
Who is likely to have osteoporosis?
POSTMENOPAUSAL/ SENILE women
What happens to PTH secretion in osteoporosis?
Diminished PTH secretion by parathyroid glands in response to hypocalcemic stimulus.
What is the difference between secondary and common osteoporosis?
Secondary = often more treatable/ reversible causes (ex. hyperthyroidism).
Common = everything else, if its not secondary.
Best prevention of osteoporosis? Predictor of risk?
- maximize peak bone mass while teen/young adult
- encourage weight bearing exercise and Ca supplementation
-Maternal hip fracture = strong predictor of risk
Who do anit-osteoporosis medications work?
Inhibit bone resorption
Is there a biochemical serum marker of bone formation and resorption?
NO! Not sufficiently standardized or studied
What is primary hyperparathyroidism?
Hypercalcemia due to primary hyperlasia or neoplastic enlargement of parathyroid glands
-spectrum of bony changes!
What is osteomalacia?
Decreased bone mineralization with excess osteoid due to interference with Ca, P, or Vit D metabolism
- Radiologically appears osteopenic
- may present with diffuse skeletal pain
What is a common cause of osteomalacia?
Liver or renal disease (impaired hydroxylation of Vit D)
What is osteomyelitis?
Infection of bone
Can be:
Primary- from blood
Secondary- from other joint or soft tissue infection
Direct- compound fractures
Most common cause of osteomyelitis?
Staph. Aureus
If sickel-cell then salmonella
Clinical presentation of osteomyelitis?
Bone pain
erythema
swelling
fever/chills variable
Best way to detect osteomyelitis?
bone scans/MRI scans better at early detection
What is often associated with osteomyelitis in adults?
diabetic vascular disease
Treatment for osteomyelitis?
AGGRESSIVE IV antibiotic therapy
What is avascular bone necrosis/ infarction?
Bone infarcts due to ischemia of varring/often poorly understood causations
Most common cause of avascular bone necrosis?
Prolonged Cortiocosteroid therapy
What is Paget’s disease?
Deforming bone disease of middle-aged to elderly adults
-latent viral infection of osteoclasts in a genetically susceptible person
What are the three phases of paget’s disease?
- Lytic (inc. osteoclast with bone resorption, increased vascularity)
- Mixed (inc. osteoclast and osteoblasts, increased vascularity)
- Sclerotic- (osteoblastic phase, most characteristic radiologically)
Clinical findings of Paget’s disease?
Usually asymptomatic
but may see WIDENING/bowing of long bones, general WEAKENING of affected bone, causing more fractures
Biochemcial give-away of Paget’s?
increased serum alkaline phosphatase (sign of bone break down) typical for active disease with normal serum calcium
Osteogenesis imperfecta?
Congenital disorders of type 1 collagen
- abnormal or not enough
- insufficient/inadequate collagen for normal osteoid production
- results in varying degrees of osteopenia/osteoporosis
Classifications of bone tumors by x-rays
Osteolytic- demineralizing effect
Osteoblastic- increased bone density relative to normal bone
Mixed
What would you think of if you saw purely osteolytic lesions?
Myeloma
Plasmacytoma
Leukemia
By definition always affects bone marrow
Where do tumors usually arise in long bones?
metaphyses
Most common primary malignant tumor of children/ young adults?
Osteosarcoma
Most common primary malignant tumor of middle-aged/oder adults?
Chondrosarcoma
What is fibroma?
benign developmental defect
most common bone lesion
Found in 1/3 of children
Ewing’s sarcoma
most leathal primary bone tumor
