CH 12--DISEASES OF BONES--Bone 2/Metabolic Diseases Flashcards
Metabolic Disorders X 5
Includes:
- Rickets & osteomalacia
- Osteoporosis
- Paget’s disease
- Fibrous dysplasia
- Hypertrophic (_____________) osteoarthropathy
pulmonary
- Rickets & Osteomalacia–1
Features:
1— Due to vitamin D deficiency mineralization of bone
2— _______ in children
3— ____________ in adults
Rickets
Osteomalacia
- Rickets & Osteomalacia–2
Sources of Vitamin D:
(1) Diet: Meat and dairy products absorbed in _________ with fats.
(2) Skin: 7-dehydrocholesterol vitamin D by UVR in _______
—Liver: Hydroxylated into 25-hydroxyvitamin D (inactive)
—Kidney: Hydroxylated in proximal tubules =
1-25 dihydroxyvitamin D (active form) = INCREASES absorption of calcium & phosphorus from intestine = ________________ of skeleton
intestine
sunlight.
Mineralization
- Rickets & Osteomalacia–3
CAUSES of vitamin D deficiency:
- Inadequate exposure to SUNLIGHT
- Dietary Deficiency of vitamin D
- Malabsorption (e.g. biliary, pancreatic or
intestinal dysfunction) - Renal failure or liver disease (reduced hydroxylation)
- _____________ depletion:
- poor intestinal absorbtion (e.g. antiacids)
- impaired reabsorbtion in renal tubules
Phosphate
- Rickets & Osteomalacia–4
Clinical Features:
(a) Rickets in growing children = Failure of deposition of calcium phosphate in zone of calcified cartilage
b. Growth of cartilage without cartilage degeneration:
(1) Wide irregular epiphyseal line
(2) EXCESS cartilage
c. FAILURE of deposition of _______ ________ in newly formed bone
d. INCREASED amount of _______ __________tissue =
SOFT EASILY DEFORMED BONE!!
calcium phosphate
uncalcified osteoid
- Rickets & Osteomalacia–5
VITAMIN D PROBLEMS: Skull: 1--Delayed closure of \_\_\_\_\_\_\_\_\_ 2--Delayed eruption of teeth 3--Excess \_\_\_\_\_\_\_ tissue at frontal and parietal prominences (frontal bossing) 4--Flattening of occipital bones
Chest:
1–Rachitic rosary: beaded costochondral junctions
2–Harrison’s sulcus: groove opposite origin of diaphragm
3–______ chest: flattening of sides & protrusion of sternum
Vertebral column:
1— Dorsal kyphosis
2—Lumbar lordosis
3—Scoliosis
Long bones:
1— __________ of weight bearing bones
e.g. tibia (forward), femur (outward)
fontanelles
osteoid
Pigeon
bending
- Rickets & Osteomalacia–6
VITAMIN D PROBLEMS CONTINUED
Osteomalacia (SOFT bone): - occurs in adults (e.g. pregnancy & lactation) = Bones need ______ and _______ to remain healthy and strong, but the body also needs vitamin D to be able to absorb these two minerals. Without this necessary vitamin, bones can become SOFT and flexible. This softening is called osteomalacia, or rickets when diagnosed in children. The condition is called osteomalacia when the bone softening occurs AFTER the growth plates have closed.
Pathogenesis: defective mineralization = soft, deformed bones = bone pain
calcium
phosphorus
- Osteoporosis–1
Features:
a— DECREASED total mass of bones (_______ = bone
atrophy)
b— Simultaneous ______ of organic matrix (osteoid
tissue) & minerals
c— Most common metabolic abnormality in USA (more than ____ million are affected and 1 million Americans experience a significant fragility fracture every year)
osteopenia
LOSS
15
- Osteoporosis–2
Etiology:
1. _________ ostoeporosis (aging): attenuated osteoblasts
2. POST-MENOPAUSAL (estrogen deficiency):
a—- _________ normally DECREASES release of IL-1
(osteoclast activation factor) from macrophages
b—- decreased estrogen levels AFTER menopause
INCREASES ____ release = stimulates osteoclasts
3. Prolonged immobilization = decreased physical
activity (disuse atrophy)
4. Endocrine disease = e.g. hyperparathyroidism
Senile
estrogen
IL-1
2. Osteoporosis--3 Clinical Features: - affects \_\_\_\_ bones - symptoms are felt in weight-bearing ones: EX. Vertebral bodies: - change in shape - decreased height - compression fractures - kyphosis, kyphoscoliosis
ALL THIS LEADS TO BACK PAIN
- -Long Bones: pathological fracture (femur neck)
- – widespread radiolucency
all
- Osteoporosis–4
Management:
- Drug therapy like “________’ to help bone build up
- Hormone replacement therapy
- Exercise, physiotherapy modalities
- Adequate dietary intake of calcium before age_____
- Adjustment (may or may not be contraindicated)
Supplementation:
- Calcium
- Vitamin D
Osteoporotic vertebral body (right) shortened by
compression fractures compared with a normal verbral
body. The lamellar bone exhibits discontinuous, thin trabeculae.—SEE SLIDE 22!! WOW!
Evista
30
- Paget’s disease–Osteitis Deformans–1
Features:
- Common disease (3-4% of population over 60 years)
- Etiology:
1. Genetics - familial incidence
- associated with certain HLA
- high prevalence among British
2. SLOW VIRUS INFECTION of ___________
osteoclasts
- Paget’s disease–Osteitis Deformans–2 = a chronic disease characterized by episodic accelerated bone resorption and growth of abnormal replacement bone, causing bone pain, deformation, fractures, and osteosarcoma; osteitis deformans.
Pathological lesions:
a—– Paget’s may involve one bone (monostotic) or many
(polystotic)
b—- Three phases: REMEMBER “L….C….B”
1— OsteoLYTIC stage:
- Focal areas of bone resorption
- Bone ____________ by vascular connective tissue
- Large osteoclasts with 12 or more hyperchromatic nuclei & virus-like inclusion bodies.
2—. OsteoCLASTIC-osteoblastic stage:
—NEW bone with _______ mineralization at margins
(tile or mosaic appearance)
3— OsteoBLASTIC stage:
- Excess osteoblastic activity → thickening of cortex & trabeculae
- SOFT, porous, poorly mineralized NEW bones
- ending in __________
replacement
decreased
osteosclerosis
- Paget’s disease–Osteitis Deformans–3
Complications: - Malignant change → osteosarcoma (2-5%) - Bone deformity or fracture - Arterio-venous fistula → a state of hyperdynamic circulation → \_\_\_\_\_\_\_\_ \_\_\_\_\_\_\_\_\_\_
heart failure
- Paget’s disease–Osteitis Deformans–4
A radiograph of the spine shows vertebrae affected by paget disease. The vertebrae are ____ and _____ than normal, and display the characteristic “picture frame” appearance.
shorter
wider
