Skel A-MEtabolic Bone Disease Flashcards by Juewuo R

Descriptive term for decreased bone or increased radiolucency of bone that occurs when bone resorption exceeds bone formation regardless of specific pathogenesis.

Osteopenia

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What results when bone resorption exceeds bone formation regardless of specific pathogenesis?

Osteopenia

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T/F: Radiographic findings of osteopenia does not alone allow a precise diagnosis

True

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What are the four major causes of osteopenia?

Osteoporosis

Osteomalacia/ Rickets

Hyperparathyroidism

Neoplasm

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Bone Cells:

Originates from the marrow stem cells, develop into osteoblasts

Osteoprogenitor cells

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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

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Bone cell:

Arises from osteoblast that become entrapped in their own osteoid.

They maintain bone integrity

Mature bone cells

Osteocytes

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Bone Cells:

Inactive/dormant osteoblast

Bone lining cells

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Bone Cell:

Bone resorptive cells, derived from hematopoietic monocyte lineage.

Different lineage from other bone cells

Osteoclast

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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

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Non-cellular constituents of bone:

% of wet weight of bone that is accounted for by water

20%

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Non-cellular constituents of bone:

% of bone weight accounted for by cellular components

Tiny fraction

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Non-cellular constituents of bone:

% of dry bone weight accounted for by organic matrix/osteoid

30%

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Non-cellular constituents of bone:

% of dry bone weight accounted for by inorganic material

70%

Accounts for 70% of osseous tissue

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Non-cellular constituents of bone:

Inorganic material exists as what ?

Calcium hydroxyapatite

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Calcium homeostasis:

Function of the skeleton in calcium homeostasis

99% of calcium stored in skeleton

Serves as a reserve for serum calcium

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Calcium homeostasis:

70% of plasma calcium is believed to be maintained how?

Continuous exchange of calcium ions between bone and extracellular fluid

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Calcium homeostasis:

The remaining 30% of plasma calcium is mediated by what?

The function of Parathyroid hormone and Calcitonin

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Osteoclast and Osteoblast function:

Osteoclast exist in pits on bone surfaced called?

Resorption bays or Howship’s Lacunae

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Osteoclast and Osteoblast function:

Osteoclast function

Secretion of Collagenase to break down osteoid

Secrete Acid to break down calcium hydroxyapatite

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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

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Osteoclast and Osteoblast function:

Substance that inhibits osteoclast

Calcitonin

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Metabolic bone disease:

Bone quantity not quality disorder

Associated with decreasing osteoblastic function with age

Estimated 30-50% loss before detectable radiographically

Osteoporosis

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Metabolic bone disease:

Where is the predominant location of osteoporosis ?

Axial skeleton

Proximal long bones

*can be generalized of localized

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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 - 1. Immobilization an disuse-fx healing 2. Complex region pain syndrome-sympathically mediation pain, Reflex sympathetic dystrophy syndrome 3. 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- 1. Discovered by Duncan et. al 2. Happens in 5-41% 3. Unpredictable 4. 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 1. Mets 2. 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: 1. Triradiate pelvis 2. Acetabular protrusion 3. Femoral and tibial bowing 4. Kyphoscoliosis 5. Endplate concavity 6. 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