Skel A-MEtabolic Bone Disease Flashcards
Descriptive term for decreased bone or increased radiolucency of bone that occurs when bone resorption exceeds bone formation regardless of specific pathogenesis.
Osteopenia
What results when bone resorption exceeds bone formation regardless of specific pathogenesis?
Osteopenia
T/F: Radiographic findings of osteopenia does not alone allow a precise diagnosis
True
What are the four major causes of osteopenia?
Osteoporosis
Osteomalacia/ Rickets
Hyperparathyroidism
Neoplasm
Bone Cells:
Originates from the marrow stem cells, develop into osteoblasts
Osteoprogenitor cells
Bone cells:
Produces osteoid which is soft material main of 90-95% collagen and 5-10% ground substance, the mucopolysaccharide.
It is numerous in growing skeleton and decrease in number and size at maturity
OSTEOBLAST
Bone cell:
Arises from osteoblast that become entrapped in their own osteoid.
They maintain bone integrity
Mature bone cells
Osteocytes
Bone Cells:
Inactive/dormant osteoblast
Bone lining cells
Bone Cell:
Bone resorptive cells, derived from hematopoietic monocyte lineage.
Different lineage from other bone cells
Osteoclast
For normal bone density what is required
Osteoblastic=Osteoclastic activity
Normal nervous system function
Normal GI, Liver, Renal Function
Dietary intake of calcium and phosphorus
Normal endocrine function
Weight bearing exercises
Non-cellular constituents of bone:
% of wet weight of bone that is accounted for by water
20%
Non-cellular constituents of bone:
% of bone weight accounted for by cellular components
Tiny fraction
Non-cellular constituents of bone:
% of dry bone weight accounted for by organic matrix/osteoid
30%
Non-cellular constituents of bone:
% of dry bone weight accounted for by inorganic material
70%
Accounts for 70% of osseous tissue
Non-cellular constituents of bone:
Inorganic material exists as what ?
Calcium hydroxyapatite
Calcium homeostasis:
Function of the skeleton in calcium homeostasis
99% of calcium stored in skeleton
Serves as a reserve for serum calcium
Calcium homeostasis:
70% of plasma calcium is believed to be maintained how?
Continuous exchange of calcium ions between bone and extracellular fluid
Calcium homeostasis:
The remaining 30% of plasma calcium is mediated by what?
The function of Parathyroid hormone and Calcitonin
Osteoclast and Osteoblast function:
Osteoclast exist in pits on bone surfaced called?
Resorption bays or Howship’s Lacunae
Osteoclast and Osteoblast function:
Osteoclast function
Secretion of Collagenase to break down osteoid
Secrete Acid to break down calcium hydroxyapatite
Osteoclast and Osteoblast function:
What are substances that can have direct or indirect influence on osteoclasts increasing their function or numbers or both?
Parathyroid hormone
Active Vitamin D
Prostaglandin E2
Thyroid hormone
Heparin
Osteoclast and Osteoblast function:
Substance that inhibits osteoclast
Calcitonin
Metabolic bone disease:
Bone quantity not quality disorder
Associated with decreasing osteoblastic function with age
Estimated 30-50% loss before detectable radiographically
Osteoporosis
Metabolic bone disease:
Where is the predominant location of osteoporosis ?
Axial skeleton
Proximal long bones
*can be generalized of localized
Metabolic bone disease:
Senile Osteoporosis is (men/women)
Post-menopausal osteoporosis is (men/women)
Senile-men
PM- women
Metabolic bone disease:
Inadequate mineralization of osteoid
Related to deficiency in calcium, vitamin D or phosphorus which can be
Deficiency caused by renal disease, sunlight deficiency, liver disease, dietary insufficiency and GI Disease
Osteomalacia
Metabolic bone disease:
Primary type of HPT characterized by?
Increase PTH production usually benign adenoma
Metabolic bone disease:
With Primary HPT you will see (hypercalcemia/hypocalcemia)
Hypercalcemia
Metabolic bone disease:
Secondary HPT Characterized by?
Abnormal stimulation of glands by sustained hypocalcemia and hyperphosphatemia
Metabolic bone disease:
Potential causes of secondary HPT
Renal disease
GI Malabsorption
Metabolic bone disease:
Tertiary HPT characterized by?
Long standing secondary HPT to the point parathyroid function is autonomous
Can be related to ectopic tissue, or paraneoplastic syndrome
Metabolic bone disease:
Function of PTH
Osteoclastic and osteocytic stimulation
Osteoblastic inhibition
Renal calcium absorption vs inhibition of phosphate resorption
Renal stimulation of 1-Alpha- hydroxylase
Indirection effect on GI absorption of calcium
Metabolic bone disease:
Function of 1-alpha-hydroxylase
Increase formation of 1-25-vitamin D
Metabolic bone disease: Hormone?
Secreted by the human parafollicular or C cells of the thyroid gland -
Controlled by the serum calcium levels
Inhibits bone calcium resorption by decreasing osteoclastic function and
May lead to hypocalcemia and hypophosphatemia
Inhibits GI calcium absorption
Stimulates osteoblastic activity
Inhibits renal tubular cell reabsorption of calcium
Calcitonin
Metabolic bone disease:
MAjor causes of generalized osteoporosis
Age related
Medication
Endocrine
Deficiency states
Alcoholism
Chronic liver disease
Anemic state
Osteogenesis imperfecta
Idiopathic condition
Metabolic bone disease:
Osteoporosis seen in -
- Immobilization an disuse-fx healing
- Complex region pain syndrome-sympathically mediation pain, Reflex sympathetic dystrophy syndrome
- Transient regional osteoporosis
Regional osteoporosis
Metabolic bone disease:
Describe CRPS/SMPS
Syndrome that typically follow trauma unilaterally
Soft tissue swelling
Very painful
Metabolic bone disease:
Transient demineralization of the hip usually in healthy middle aged men, and pregnant women in 3rd trimester
Affects left hip
Acute pain & functional disability w/o previous trauma
Clears up on its own-self limiting
Transient osteoporosis of the hip
Metabolic bone disease:
Osteoporosis-
- Discovered by Duncan et. al
- Happens in 5-41%
- Unpredictable
- Affects joint nearest the disease
Regional migratory osteoporosis
Metabolic bone disease:
6 vertebral configurations in osteoporosis
Normal
Losing horizontal trabeculation
Anterior wedging
Plana: ant/post collapse
Bison cave endplates
Angular endplate depression from fox
Metabolic bone disease:
Plana vertebrae in osteoporosis may be caused by ?
Malignancies
- Mets
- Mult. Myeloma
Metabolic bone disease:
Biconcave endplates in osteoporosis may be caused by?
Mult. Myeloma 5
Metabolic bone disease:
Fx- Cause by Osteoporosis
Low extremity bilaterally
Pain major symptom
Occurs when elastic strength < normal phys stress
Insufficiency Fox
Metabolic bone disease:
Risk factors of osteoporosis
ACCESS
Alcohol
Corticosteroids
Calcium low
Estrogen low
Smoking
Sedentary lifestyle
Metabolic bone disease:
Scan for bone density
Duel Energy X-ray Absorptiometry
DEXA/DXA
Metabolic bone disease:
Associated with long term vitamin C deficiency
Predominantly in children
Scurvy/Barlow’s disease- hypovitaminosis C
Metabolic bone disease:
What is the hallmark Scurvy?
Spontaneous bleeding due to capillary fragility
SUBPERIOSTEAL BLEEDING —>BONE PAIN
Radiographic finding of Scurvy:
dense zone of provisional mineralization- no secondary spongiosa
White line of frankel
Radiographic finding of Scurvy:
Dense cortical margin of epiphysis with radiolucent center
Wimbergers ring
Radiographic finding of Scurvy:
Irregular mataphyseal margin
Corner/angle sign
Radiographic finding of Scurvy:
Bony protuberance at margin of ZPM
Spurs
Pelken sign
Radiographic finding of Scurvy:
Radiolucent metaphyseal band directly beneath ZPM, due to defective bone formation
Trumerfeld/subortic line
Leukemia lines in leukemia
Radiographic finding of Scurvy:
Pathognomonic sign visible with healing
SUBPERIOSTEAL hemorrhage
Metabolic bone disease:
Clinical findings of hypovitaminosis D
Muscle weakness
Bone pain
Deformities of pelvis, femur, tibia and spine
Radiographic features of osteomalacia:
What are the radiographic features of osteomalacia ?
Osteopenia
Coarse do trabecular pattern
Loss of cortical definition
Pseudo fx
Radiographic finding of osteomalacia:
Deformities seen on radiograph
Weight bearing bones:
- Triradiate pelvis
- Acetabular protrusion
- Femoral and tibial bowing
- Kyphoscoliosis
- Endplate concavity
- Bell shaped thorax
Radiographic finding of osteomalacia:
Common sight of osteomalacia
Femur
Ribs
Axillary border of scapula
Pelvic rami
Radiographic finding of osteomalacia:
AKA for pseudo fx
Umbauzonen/increment fx
Looser’s lines
Milkman syndrome
Osteoid seams
Pseudo fx:
Characterized by
Seam of unmineralized osteoid
No trauma
Perpendicular to cortex
Ribs, pelvis, femur, no spine involvement
Bone softening disease
Metabolic bone disease:
Renal tubular loss of phosphorous, not cured by the administration of vitamin D
Resistant/refractory/ renal rickets
Metabolic bone disease:
Secondary HPT + renal rickets =
Renal osteodystrophy
Clinical presentation of rickets
Muscle tetany
irritability
weakness
delayed bone development
small stature and bone deformities/bowing
T/F: findings of enlarged growth plates (trumpeting) and rib ends (rachitic rosary) are present in rickets
True
Metabolic bone disease:
Generally an x-linked transmitted
Renal tubular loss of phosphate
Rickets develops
In adults skeleton, develops osteosclerosis and enthesopathic paravertebral ligament
Lumbar stenosis
Type of dwarfism
Hypophosphatemia
Metabolic bone disease:
Hypophosphatemia is classified under which group of syndromes?
Fanconi syndrome
Metabolic bone disease:
Rare disease related to low serum alkaline phosphatase produced by osteoblasts
Resembles rickets
Radiolucent metaphyseal defect from physis to metaphysis
Hypophosphatasia
Metabolic bone disease:
Hypophosphatasia is a mineralization disorder
True, however it doesn’t have to due to with mineral deficiency.
It is the linking of the hydroxyapatite to osteoid that is absent
Metabolic bone disease:
Histology also changes of HPT
Bone resorption with fibrous tissue replacement
Metabolic bone disease:
Major bone changes in HPT
Osteopenia
Accentuated trabecular pattern
Loss of cortical definition
BROWN TUMORS
Subperiosteal bone resorption
Metabolic bone disease:
hallmark HPT finding
Superiosteal bone - pathognomonic in the hands
Metabolic bone disease:
HPT CLinical findings
3:1 Female :male 30-50 yoa
Found accidentally by dentist
Hypercalcemia, weakness, lethargy, poly dips is, polyuria, renal calculi, bone tenderness
AKA for renal osteodystrophy
Uremic osteodystrophy
HPT bone changes:
In many location but in the middle phalanx of the hands on the radial aspect is pathognomonic
2-4 digits
Subperiosteal bone resorption
HPT bone changes:
Within harversion canals
Linear striations in long bones
Intracortical bone resorption
HPT bone changes:
Typically hands and with other findings
Endosteal bone resorption
HPT bone changes:
Common, SI, SC, AC, SP (symphysis pubis), and DV junction, can mimic inflammatory joint disease in SI joint sacroiliitis; DRA (dialysis
related arthropathy), DRSA (dialysis related spondylo-arthropathy)
Subchondral bone resorption
HPT changes:
Diffuse in skeleton, very prominent in cranium, causes very granular appearance to diploic space “salt and pepper” or “pepper pot skull”
Trabecular bone resorption
HPT changes:
At entheses; trochanters, ischial and humeral
tuberosities, elbow, calcaneus, inferior distal end of clavicle
Subligamentous bone resorption
HPT changes:
localized cyst-like bone resorption containing (overcummulation) fibrous tissue & blood, giant cells and
hemorrhages
Brown tumor
HPT changes:
distal tuft resorption (of fingers), seen with many other conditions
- Look at hands!!!
Acro-osteolysis
Brown tumor and chondrocalcinosis are common in (primary/secondary) HPT
Primary
Osteoscelrosis and periostitis more in (primary/secondary) HPT
Secondary
Serum (-) Rheumatoid types
Rheumatoid arthritis System lupus erythematous Progressive systemic sclerosis Dermatomyositis/polymyositis Transient: viral infection
Serum (+) rheumatoid variants
Ankylosing spondylitis
Reiter‘ s syndrome aka Reactive arthritis syndrome
Psoriatic arthritis
Inflammatory bowel disease
