Bone Pathology - Sheet1 Flashcards
non-neoplastic bone disease
fractures involving healthy bone, osteoporosis (esp post menopausal) AND associated fractures, osteomalacia, osteomyelitis, avascular bone necrosis/infarction.
osteopenia differential
(decrease in bone mineralization) associated with osteoporosis (common), osteomalacia, malignancy, rare hereditary disorder.
osteomalacia definition
Definition: decreased bone mineralization with excess osteoid (wide osteoid seams)
Radiologically appears osteopenic (like osteoporosis) May present with diffuse skeletal pain (without fracture)
metastatic tumors to skeleton
neoplasm that is secondary metastatic site (from non-bone primary sites)
What is a pathological fracture?
fracture thorugh diseased bone
usually refers to fracture through tumorous or tumor-like bone
periosteum–Its response to trauma…
Periosteum functions to **repair bone **
full of nerves (so this hurts when you get kicked!)
puberty does what to the cartilagenous epiphyseal plate?
promotes vacularization… which promotes cartilage calcification.
What are the two critical regulatory molecules/enzymes for calcium homeostasis?
PTH and Vitamine D(OH)2
What vitamin is required for normal mineralization of bone osteoid?
Vit D(OH)2
Name some possible complications of healing bone
mal-alignment, non-union, mal-union, osteomyelitis, growth disturbance via breaking of epiphyseal plate), arthritis,
osteoporosis
A type of osteopenia due to bone atrophy caused by an imbalance of the bone remodeling process.
No markers, no clinical manifestations.
Currently defined as bone mineral density ≥ 2.5 standard deviations.
What are common observations for osteoporosis
kyphosis,
vit D(OH) –> Vit D(OH)2 rxn impaired = Diminished PTH
Why should osteoporosis be a diagnosis of exclusion?
Remember the often more treatable / reversible causes of secondary osteoporosis such as osteopenia (differential?)
Decreased bone mineralization (osteopenia) does not automatically = osteoporosis
What are the two most common causes of osteopenia?
decreased bone density; osteoporosis and osteomalacia
Best prevention for osteoporosis?
maximize peak bone mass (teens/young adults)
Primary Hyperparathyroidism
Hypercalcemia due to primary hyperplasia or Neoplastic enlargement of parathyroid glands.
High PTH promotes osteoclastic bone resorption/peritrabecular fibrosis = osteitis fibrosa.
Classic Primary Hyperparathyroidism
asymptomatic and detected on biochemical screening studies primary type — *increased Ca and decreased P*
Osteomalacia in children is called?
Rickets
Osteomalacia: Biochemical profile/Labs
increased serum alkaline phosphatase (>90%)
Low serum Ca or P (50%)
Decreased urinary Ca excretion (33%)
increased PTH (40%)
Decreased 1, 25 dihydroxyvitamin D3 (50%)
Parathyroid hormone
At low levels –> exerts anabolic effects (building bone) on osteoblasts and osteoclasts (indirect).
Chronic high PTH levels (primary hyperparathyroidism) –> causes an increase in blood [Ca++].
What is the best prevention for osteoporosis?
maximize peak bone mass (teens/young adults) encourage weight-bearing exercise and Ca supplementation
Bone pain, fever, local swelling and erythema, and no trauma. What should you think of?
Osteomyelitis
Staphylococcus aureus (95%)
Treatment is aggressive I.V. antibiotics.
Most common cause of fungal osteomyelitis in non-immunosuppressed patients
Blastomycosis and coccidioidomycosis
Avascular bone necrosis/infarction
infarction due to ischemia
Clinically: subchondral infarcts, medullary infarcts, multiple infarcts.
Common causes: femoral neck fractures or chronic corticosteroid Rx, SLE.
Treatment: often requires joint replacement
