Pathology III Bone Tissue

Question 1

Cretinism or “Christ-like”

Answer 1

Is one of the disorders of the growth plate

Question 2

A 3 y/o pt. presents with mental retardation, dwarfism, and a failure of fontanelle closure. The pt. was born with umbilical hernias, coarse facial features, and hypotonic posture. Mother had iodine deficiency while pregnant.

Answer 2

Cretinism

Question 3

Why are the children mentally retarded in cretinism?

Answer 3

defective issues in the formation of the neural tube

Question 4

Why do we used iodinated salt in the US?

Answer 4

To prophylax

maternal iodine deficiency leads to cretinism

Question 5

What do you look for in fontanelle closure?

Answer 5

Look at the front of the children’s heads

Question 6

Which cells are affected in cretinism?

Answer 6

Chondrocytes do not follow an orderly progression and there is a failure of ossification

Question 7

How is cretinism different from achondroplasia?

Answer 7

The dwarfs are not mentally retarded in achondroplasia

Question 8

How is cretinism tx?

Answer 8

Many Sx are resolved by administering thyroid hormone

Question 9

A 9 y/o presents with mental retardation, corneal opacities, hearing defects, cardiac valve disturbances, and DENTAL DEFECTS. What is the mechanism of this disorder?

Answer 9

A deposition of glucosaminoglycans in developing bones

MORQUIO SYNDROME

Question 10

What type of mucopolysacchariodosis is morquio syndrome?

Answer 10

Type IV

Question 11

Compare morquio syndrome to cretinism and achondroplasia

Answer 11

A severe form of dwarfism but overall more like cretinism than achondroplasia

Question 12

A dwarf patient has the head of a typical size with a small body

Answer 12

Achondroplastic patient

Question 13

What causes achondroplasia

Answer 13

the arrest of the growth plate

Question 14

What type of dwarfism is presented in achondroplasia

Answer 14

An inheritied dwarfism

Question 15

What is the most common disease of the growth plate?

Answer 15

Achondroplasia

Question 16

A pt whose heterozygous parents are affected shown sign of dwarfism with shorted limbs

Answer 16

Achondroplsia

Autosomal dominant condition
Decrease of paracrine signaling (FGF)
The parents will have 25% change of having normal children

Question 17

Type I collagen disease

Answer 17

Osteogenesis imperfecta or “brittle bone disease”

A defect in the extracellular protein, collegen I

Question 18

In addition to skeleton, what other sites are affected in osteogenesis imperfecta?

Answer 18

The sites highly rich in type I collagen : 
joints
eyes 
ears 
skin
teeth

Question 19

Where is the deficiency in type I collagen?

Answer 19

Osteoblasts

Question 20

Type I collagen are mainly present in what?

Answer 20

Bone and sclera (fibrocartilage)

Question 21

Diagnosis of osteogenesis imperfecta

Answer 21

Presence of BLUE SCLERA

Question 22

A Pt. presents with multiple fractures in the lower limbs over the course of a few years. Physical exam reveals blue sclera. The pt. opts for amputation.

Answer 22

Osteogenesis imperfecta

Question 23

What condition, other than osteogenesis imperfecta, can cause blue sclera?

Answer 23

Tetracycline overdose- will also cause blue ears

Question 24

Diseases associated with defects in metabolic pathway

Answer 24

Osteopetrosis

Question 25

Why is the juvenile version of osteopetrosis lethal?

Answer 25

Because the calvarium gets very thick in this case and causes herniation of the brain through foramen magnum, atlas, axis, and vertebral canals

Question 26

Osteopetrosis

Answer 26

marble bone disease (marbles are rocks) and "albers-shonberg disease"

Question 27

What does diffuse skeletal sclerosis mean in osteopetrosis

Answer 27

Sclera = means hard Petro=rock like e.g. petrous part of the temporal bone The bones are abnormally brittle and fracture like a piece of CHALK

Question 28

What happens to the bones in the body of someone who has osteopetrosis?

Answer 28

The rate of synthesis > the rate of degradation | So over time, the bones of the body become very large

Question 29

What is unique about the architecture of the bone in osteopetrosis?

Answer 29

Not the way it should be like a trabecular bone (with proper arrangement and collagen deposition) -Cannot resist tensile forces the way most bone can

Question 30

Osteopetrosis: Autosomal Recessive vs dominant

Answer 30

Malignant - recessive Benign - dominant serious genetic defects tend to be recessive since people don't make it to reproductive age

Question 31

4 types of osteopetrosis

Answer 31

Infantile malignant form (letal) Type II carbonic anhydrase deficiency - probably an inability to produce carbonic acid in order to breakdown the bone Autosomal dominant type I and II

Question 32

3 stages of Paget Disease

Answer 32

osteoclast dysfunction 1. osteolytic stage 2. mixed osteoclastic-osteoblastic stage 3. predominant osteoblastic acitivity

Question 33

What age group for paget?

Answer 33

Adults!

Question 34

Differentiate osteoporosis from pager's

Answer 34

age of onset!!!! | PAGET starts mid-adulthood

Question 35

What geographical location is paget RARE?

Answer 35

asia and africa

Question 36

Which cytokine is a potent osteoclastic stimulator?

Answer 36

IL-6

Question 37

Paramyxovirus causes IL-6 to be released and cause what disease?

Answer 37

PAGET

Question 38

Chalk-like fx are present in which two diseases?

Answer 38

osteopetrosis and PAGET

Question 39

How does Paget become noticeable in clinical setting?

Answer 39

incidental by x-ray - big bones paget is benign won't present with a lot of sx

Question 40

Lab tests that indicate PAGET's ?

Answer 40

increase serum hydroxyproline increase serum alkaline phosphatase indicate bone breakdown (initial problem)

Question 41

Anterior bowing

Answer 41

shown in pager's disease because femur is affected | this is different from lateral bowing in rickett's and osteomalacia

Question 42

A 30 year old patient complains of pain in the leg and presents with anterior bowing

Answer 42

paget's pain caused by bone overgrowth and compression of nerves also vessels are compressed and cause ischemia

Question 43

What are the two serious complications of Paget's ?

Answer 43

osteoarthritis increased risk of malignant osteosarcoma increased association with arteriovenous malformation

Question 44

Osteosarcoma resulting from Paget's

Answer 44

FIND THE NODULES OF OSTEOSARCOMA AT THE SPINE (doesn't break the rule of primary osteosarcoma since in this case it is secondary to another disease like paget's) look elsewhere in the body to find nodules at above and below the knee also look for serum levels of hydroxyproline and alkaline phosphatase

Question 45

AV shunting in Paget's

Answer 45

high cardiac output heart failure redness over AV shunt on chest

Question 46

Vit D deficiency

Answer 46

Rickett's Osteomalacia bone isn't formed properly because ineffective mineralization of the osteoid secreted by osteoblasts

Question 47

Differentiate Rickett's from Osteomalacia

Answer 47

Rickett's in KIDS | Osteomalacia in ADULTS

Question 48

Hyperparathyroidism

Answer 48

PTH plays a central role in calcium homeostasis by stimulating osteoclasts to increase bone resorption = MOBILIZE CALCIUM

Question 49

The patient has high serum calcium and PTH levels

Answer 49

suspect hyperPTH

Question 50

Hypercalcemia

Answer 50

cause dementia

Question 51

Vit D synthesis is stimulated by which hormone?

Answer 51

PTH

Question 52

a osteoporotic patient is given calcium. the person developed parathyroid tumor, what happens?

Answer 52

more PTH released more calcium in the system DEMENTIA

Question 53

Iatrogenic dementia

Answer 53

from calcium supplement to patients with osteoporosis who develops PTH tumor

Question 54

Osteomyelitis

Answer 54

inflammation of bone and marrow

Question 55

A patient infected with s. aureus who inflammation of the bone and marrow

Answer 55

pyogenic osteomyelitis blood-borne through vasculature

Question 56

A sickle cell patient infected with what agent will have inflammation of the bone and marrow

Answer 56

salmonella | pyogenic osteomyelitis

Question 57

A patient infected with TB will develop mycobacterial osteomyelitis

Answer 57

POTT's disease

Question 58

What is pot's disease

Answer 58

mycobacterial osteomyelitis