Metabolic Bone Disease- Yoho Flashcards
_____ produce osteoid matrix an amorphous ground substance and collagen matrix
osteoblasts
Bone is made of …
ions having crystallized (hydroxyapatite) on the osteoid matrix forming the bone unit
Composition:
Water (8%)
Organic substance (21%)
Inorganic substance (71%)
cortical bone is black in ____ and white in _____
MRI
CT scan
Osteoblasts make osteoid from ______
albumin
process is aided by vitamin A and C, estrogen and growth hormone
osteogenesis is stimulated by … (2)
Stimulated by a low oxygen tension and acidic environmentAided by a local alkaline environmentwhy you measure alkaline phosphatase**
Mineralization or calcification is triggered by
the high affinity of osteoid matrix for hydroxyapatite
dissolution of bone
Osteolysis
Osteoclasts and PTH hormone stimulate an acid phosphatase to proteolytic action on the osteoid crystals
Osteoclasts are stimulated by
Osteoclasts are stimulated by high oxygen tension
Aided by an acidic environment and a decrease in calcium and phosphate ions
a descriptive term for a loss of bone density observed radiographically
Osteopenia
**50% bone loss is clinically significant
30% bone loss is radiographically detectable
quantification of bone loss tools
DEXA or ultrasound as T-scores and Z-scores
T-Score related to young adult
normal— Bone density is within 1 SD (+1 or −1) of the young adult mean.
low bone mass — Bone density is between 1 and 2.5 SD below the young adult mean (−1 to −2.5 SD).
osteoporosis —Bone density is 2.5 SD or more below the young adult mean (−2.5 SD or lower).
severe oseoporosis — Bone density is more than 2.5 SD below the young adult mean, and there have been one or more osteoporotic fractures.
Z- Score
age and gender matched
define generalized osteoporosis
Definition: decrease in bone density (mass per unit volume) of mineralized boneclinical and lab correlation required for classification
radiographic findings for osteoporosis
Diminished bone density
Cortical thinning with endosteal resorption
Preferential resorption of transverse trabeculae
Anterior wedging of the vertebral bodies (dowager’s hump)
how does scurvy cause generalized osteoporosis?
Vitamin C deficiency Osteoblasts fail to produce osteoid Lack of mineralization Alcoholism/starvation Slow wound healing, peau de orange Hemorrhagic cutaneous lesions
radiographic findings for scurvy
White line of scurvy Bone spicules at metaphyseal margins (Pelkin’s sign) (small arrows of washed out bone)
Corner sign (washed out bone in corner)
Trumifield zone
Epiphyseal displacement
Ringed epiphysis (preferential washing out of epiphysis)
Cortical deossification with ground glass appearance, its going to be generalized throughout the body
osteomyelitis and tumors cause what type of osteoporosis
localized osteolytic osteoporosis
CRPS chronic regional pain syndrome osteoporosis
sudeck’s atrophy - localized osteoporosis
early –> final lcoalized osteoporosis radiographic findingings
Early: spotty loss of density with irregular rarefaction, loss of sharp outline of the articular cortex
Later: periarticular deossification
Final: uniform loss of density with a thin well-defined cortex
**In tumors and infection the process if referred to as lysis (lytic lesions)
CRPS complex regional pain syndrome stages
Stage I: Acute
Stage II: Dystrophic
Stage III: Atrophic
describe sudeck’s atrophy
Patchy osteoporosis
Accentuated joints
Subchondral bone resorption
Ground-glass appearance
Defect in calcification with increased accumulation of uncalcified osteoid
Osteomalacia/Rickets
Vitamin D deficiency
Renal tubular insufficiency
Non-resorptive process
**Skeletal deformity*
radiographic findings osteomalacia
Generalized decrease in bone density Loss of trabecular detail Cortex may be thin and lack definition Skeletal deformities Looser’s lines (milkman's false fx)
radiographic findings Rickets
- Widening of epiphyseal plate with a frayed appearance
- Irregular zone of provisional calcification
- Metaphyseal cupping
- Milkman’s fracture
