18: Radiology of 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 black =
white =
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 environment
Aided by a local alkaline environment
why 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 bone
clinical 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
radiographic features of endocrinopathies
Subperiosteal resorption
Generalized loss of bone density
Terminal tuft resorption
Brown tumors**
Soft tissue calcifications
name the marrow packing disorders
Thalassemia
Multiple Myeloma
Leukemias
Radiographic findings: Hyperplastic marrow response Expansile areas of lytic destruction Periosteal new bone formation Pathologic fracture
a descriptive term for an increase in bone density observed radiographically
Osteosclerosis
Mechanisms responsible:
Failure of primary spongiosa to be absorbed in the metaphysis during enchondral bone formation
Errors of internal modeling of compacta and spongiosa
Stimulation of normal endogenous osteoblasts to form excessive new bone
describe paget’s disease
Incidence: 5th decade
Sites: skull, spine, pelvis and major long bones
Skeletal pain and deformity (increase in size)
tests: Alk Phosphatase, N-telopeptides and deoxypyridinoline
radiographic findings for paget’s disease
Lytic phase
- Destructive changes
- Flamed shaped-lesions***
- Osteoporosis circumscripta
Sclerotic phase
- Bizarre new bone formation
Combined phase
Malignant transformation (osteogenic sarcoma)
Failure to absorb primary spongiosa
Osteopetrosis
radiographic findings osteopetrosis
- Uniform increase in bone density
- Loss of distinction between cortical and medullary bone
- Erlenmeyer flask appearance of tubular bones
- Bone within bone appearance
- Fractures are common
radiographic findings osteopoikilosis
- Multiple round/ovoid bone densities
- Few mm to several cm
- Non-progressive
- Metaphyseal and epiphyseal involvement in long bones
Hereditary bone disorder
Unknown etiology
Incidental finding
Heterotrophic soft tissue ossification
Myositis Ossificans
will have hx of trauma
Radiographic Findings:
- Ill-defined calcifications
- -Organization into bone
- Follows axis of muscle
- Adjacent periosteum may show changes
- Differentiate from sarcoma
