CONGENITAL AND DEVELOPMENTAL BONE DISEASES

Question 1

Developmental abnormalities of the skeleton are
frequently? Based

They become manifest during ?

Answer 1

genetically

manifest during earliest stages of bone
formation.

Question 2

Acquired diseases are detected in?

Answer 2

adulthood

Question 3

brittle bone disease

Also known as?

Answer 3

Osteogenesis Imperfecta

Question 4

group of genetic disorders

characterized by brittle bones ?

Answer 4

Osteogenesis imperfecta

Question 5

Hereditary disorders caused by ?

Answer 5

defective synthesis of type I
collagen.

• type I collagen is a major component of extracellular
  matrix in other parts of the body, there are also extra-skeletal
  manifestations

Question 6

Pathogenesis of Osteogenesis Imperfecta?

Answer 6

Results from autosomal dominant mutations in genes that coding
sequences for α1 or α2 chains of type I collagen.

Question 7

Osteogenesis Imperfecta Subtypes?

Answer 7

Has 4 subtype, the most important are I&II

1. Patients with type I have a normal lifespan, with only a
   modestly increased risk to fractures during childhood.

Question 8

Osteogenesis Imperfecta type 1

finding ?

Answer 8

• Blue sclera caused by decreased collagen content.
• Hearing loss due to abnormalities in the bones of middle and
inner ear.
• Dental imperfections ( small, misshapen and blue-yellow teeth).

Question 9

Osteogenesis Imperfecta

.Type II variant is ?

Answer 9

fatal pre- or immediately post-partum
due to multiple fractures that occur in utero.
B

Question 10

most common disease of growth plate. ?

Answer 10

Achondroplasia

Question 11

Major cause of dwarfism.

?

Answer 11

Achondroplasia

Question 12

Achondroplasia pathogenesis?

Answer 12

• transmitted as an autosomal dominant trait but many cases arise from spontaneous mutation resulting from:

1. Defect in the cartilage synthesis at growth plates due to
   gain-of-function mutations in the FGF receptor 3 (FGFR3).
   =
   a receptor with tyrosine kinase activity that transmits intracellular
   signals.
   =
   Signals transmitted by FGFR3 inhibit the proliferation and
   function of growth plate chondrocytes
   =
   , the growth of normal epiphyseal plates is suppressed

Question 13

characterized by failure of cartilage cell proliferation at the epiphysial plates of the long bones, resulting in failure of longitudinal bone growth and subsequent short limbs
?

Answer 13

Achondroplasia

Question 14

Clinical Achondroplasia?

Answer 14

• Individuals have shortened proximal extremities.
• A trunk of normal length.
• Enlarged head with bulging forehead.
• Depression of the root of the nose.
• Skeletal abnormalities are not associated with changes in
longevity, intelligence and reproductive status.

Question 15

A condition of skeletal fragility characterized by compromised
bone strength predisposing to an increased risk of fracture. ?

Answer 15

OSTEOPOROSIS

Question 16

Peak bone mass is achieved during young adulthood. Its magnitude
is determined largely by ?

Answer 16

hereditary factors, especially

polymorphisms in the genes that influence bone metabolism.

Question 17

important contributions

Of OSTEOPOROSIS?

Answer 17

Physical activity, muscle strength, diet, and hormonal state

Question 18

Factors that can lead to osteoporosis?

Answer 18

- nutrition: 
Vitamin D and calcium 
- physical activity: 
- aging : 
Dec activity of osteoprogenetal cell 
Dec. osteoclasts 
Reduced physical activity 
-menopause: 
Dec estrogen 
Inc expression of RANK 
Inc osteoclasts 

=
Osteoporosis

Question 19

Primary osteoporosis?

Answer 19

• most menopausal

- senile (aging )

Question 20

Secondary osteoporosis?

Answer 20

• endocrine disorder :
  Hyperparathyroidism
• liver and kidney disease
• intestine disorder

Question 21

the “silent disease?

Answer 21

Osteoporosis

Question 22

Symptoms of osteoporosis?

Answer 22

• bone loss without symptoms.
• Onset occurs with sudden strains, bumps, or fall causes a fracture or a vertebra to collapse.
• Collapsed vertebrae may be seen in the form of severe back pain, loss of height, or spinal deformities such as kyphosis or stooped posture .

Question 23

difficult condition to diagnose
accurately, since it remains asymptomatic until skeletal
fragility is well advanced. ?

Answer 23

Osteoporosis

Question 24

Osteoporosis

The best procedures to accurately estimate the amount of
bone loss, aside from biopsy, are ?

Answer 24

specialized radiographic
imaging techniques, such as dual-energy X-ray
absorptiometry (DEXA) and quantitative computed
tomography, which measure bone density.

Question 25

group of rare genetic disorders characterized by reduced osteoclast-mediated bone resorption and therefore defective bone remodelling.

Answer 25

OSTEOPETROSIS

Question 26

bones are abnormally brittle and fracture easily, like a piece of chalk. ?

Answer 26

OSTEOPETROSIS

Question 27

There are two different genetic and clinical forms of the | disease\ osteopetrosis ?

Answer 27

1- The autosomal recessive form runs a "malignant" course and is fatal in utero, infancy or young adult life as a result of bone marrow obliteration, profound anemia, or other hemopoietic abnormalities. 2- The autosomal dominant form has a more benign course marked by repeated fractures on slight trauma, a near normal life expectancy, and the absence of hematopoietic abnormalities.

Question 28

he long bones of the extremities, vertebrae, pelvic bones, and base of the skull show a great increase in the density and thickness of the cortex. ?

Answer 28

Osteppetrosis

Question 29

An increase in the number and size of bony trabeculae, and a marked reduction or obliteration of the marrow spaces . ?:

Answer 29

Osteopetrosis

Question 30

The reduction in the total amount of bone marrow leads to anemia and extramedullary hemopoiesis, resulting in enlargement of the spleen, liver, and lymph nodes.

Answer 30

Osteopetrosis

Question 31

Bone overgrowth at the base of the cranium causes narrowing of the optic foramina and pressure on the optic nerves, resulting in blindness.

Answer 31

Osteopetrosis

Question 32

The bone tissue formed is largely woven bone, and very little of it is remodeled and replaced by lamellar bone.

Answer 32

Osteopetrosis

Question 33

Disorder of bone remodeling resulting excessive bone resorption followed by disorganized bone replacement. ?

Answer 33

PAGET DISEASE OF BONE (Osteitis Deformans)

Question 34

PAGET DISEASE OF BONE | Also known as ?

Answer 34

Osteitis Deformans

Question 35

• Thick but weak bone. • Susceptibility to deformity and fracture. • Forms of involvement:

Answer 35

PAGET DISEASE OF BONE (Osteitis Deformans)

Question 36

involving one bone | ?

Answer 36

Monostotic

Question 37

involving multiple bones ?

Answer 37

Polyostotic

Question 38

PAGET DISEASE OF BONE (Osteitis Deformans) | Commonly involve ?

Answer 38

skull, pelvis, femur and vertebrae.

Question 39

3 stages: | Of PAGET DISEASE OF BONE (Osteitis Deformans)

Answer 39

1) Osteolytic; osteoclastic activity predominates 2) Mixed osteolytic and osteoblastic 3) Osteosclerotic; osteoblastic activity predominates

Question 40

Microscopically PAGET DISEASE OF BONE (Osteitis Deformans)

Answer 40

there is haphazard arrangement of cement | lines creating mosaic pattern of lamellar bone.

Question 41

Radiographs ? PAGET DISEASE OF BONE (Osteitis Deformans)

Answer 41

enlarged bones with lytic and sclerotic areas. ] Elevated alkaline phosphatase and urinary hydroxyproline.

Question 42

Prone to develop osteosarcoma. | ?

Answer 42

PAGET DISEASE OF BONE (Osteitis Deformans)

Question 43

affect growing children ? affecting | adults

Answer 43

RICKETS AND OSTEOMALACIA

Question 44

RICKETS AND OSTEOMALACIA They may result from ?

Answer 44

diets deficient in calcium and vitamin D, but probably more important is limited exposure to sunlight.

Question 45

Both diseases are characterized by decreased mineralization | of newly formed bone. ?

Answer 45

RICKETS AND OSTEOMALACIA

Question 46

occur in children prior to closure of epiphyses. | ?

Answer 46

Rickets

Question 47

Rickets which formation is effected ?

Answer 47

Enchondral bone formation is affected leading to skelatal | deformities.

Question 48

Rickets clinically ?

Answer 48

1. Craniotabes and frontal bossing 2. Pigeon breast deformity 3. Lumbar lordoses (Spinal curvature) 4. Bowing of the legs ( Curvature of femur and tibia) 5. Overgrowth of cartilage or osteoid tissue at the costochondral junction, producing the "rachitic rosary

Question 49

impaired mineralization of osteoid matrix resulting in thin fragile bones susceptible to fracture. ?

Answer 49

Osteomalacia

Question 50

Clinically present Osteomalacia?

Answer 50

bone pain and fractures of vertebra, | hips and wrist.

Question 51

Osteomalacia Radiographs? Labs?

Answer 51

diffuse radiolucency of bone. • Labs show low serum Calcium and Phosphorus with high alkaline phosphatase.

Question 52

HYPERPARATHYROIDISM primary and secondary?

Answer 52

Primary results from hyperplasia or tumor , tends to be severe. • Secondary is caused by prolonged state of hypocalcemia; relatively mild. • Skeletal manifestations are caused by osteoclastic bone resorption. • Increased osteoclastic activity affects cortical bone.