Metabolic Bone Disease

Question 1

What does PTH do to calcium and phosphate

Answer 1

always increases serum calcium

PTH:

Kidneys: phos. wasting
Bone: increases phos. release
Serum: deceases phosphate

Question 2

What does Vitamin D do to calcium and phosphate?

Answer 2

always increases serum calcium and phosphate through mineralization, GUT and Kidneys

Question 3

PTH mechanism of action

Answer 3

Binds to osteoblasts–> Osteoblasts bind to RANK on osteoclasts —> calcium release

Question 4

what are effected in ext. bone diseases?

Answer 4

serum calcium usually affected

Question 5

Primary HPTIism labs?

Answer 5

high calcium, high PTH, high/normal Alk phos (marker of bone turnover)

Question 6

primary HPTism presentation?

Answer 6

kidney stones, gi issues, bone turn over, psychiaytric

Question 7

Osteitis Fibrosa Cystica is cause by what?

Answer 7

Hyperparathyroidism

• the bone is resorbed causing cystic bone lesion “Brown Tumor”

Question 8

2nd hyperparathyroidism causes?

Answer 8

chronically high phosphate and/or low calcium

Question 9

2nd HTPism lab findings?

Answer 9

low/normal calcium

very high PTH- trying to elevate calcium

Very high ALK phos- bone turn over

Question 10

2nd HPTism presentation

Answer 10

serum calcium WILL NOT be elevated

high bone turnover rate

OFC and brown tunmor

Question 11

Renal Osteodystrophy is seen with what?

Answer 11

chronic kidney disease , causes secondary hyperparathyroidism

Question 12

High Turn over RO etiology?

Answer 12

Kidney failure

decreases kidney phosphate excretion–>
leads to increased serum phosphate—>

1) Phosphate binds to serum Calcium —> decreased calcium
2) Phosphate inhibits hydroxylation of D3–> calcium, goes down

BOTTOM LINE:
Decreased Calcium and Phosphate= 2nd HPTism

Deceased Vit D3 –> Osteomalacia

Question 13

Late Renal Osteodystrophy shows what?

Answer 13

Will produce soft tissue calcification AND osteosclerosis

Question 14

What is tertiary hyperparathyroidism

Answer 14

desensitization of pth receptors

Question 15

How does low turn over renal OD work?

Answer 15

Aluminum is deposited in bone mineralization site —> impaired osteoclasts and blasts

Question 16

treatment for low turn over RO?

Answer 16

Po4 binding agents, alum. chelators, vit d replacement

Question 17

Hypothyroidism labs?

Answer 17

low calcium and high po4?

Question 18

What is Albright Hereditary OD?

Answer 18

hypothyroidism…end organ resistance to PTH

Question 19

Physical exam of Hypocalcemia?

Answer 19

Troussea’s Sign– hand spasm

Chvostek Sign– eye twitching

Question 20

Osteomalacia/ and Rickets pathogenesis

Answer 20

Defective mineralization of normal osteoid

• bones are soft
• Low serum calcium

CA X Po4 > 30—-> poor mineralization

Question 21

causes of rickets

Answer 21

vitamin d deficiency

malnutrition

renal failure

lack of sun

Question 22

Hereditary Vit D. Dependent Rickets Type 1

Answer 22

defect in hydroxylase enzyme

Question 23

Hereditary Vit D. Dependent Rickets Type 2?

Answer 23

Defect in intracellular receptor

Question 24

hypophasphatemic rickets?

Answer 24

kidneys cannot reabsord phosphate

Question 25

hypophosphatasia?

Answer 25

dont have enough alk phos.

Question 26

rickets presentation?

Answer 26

bone pain, limp (bow legs), rosary

Question 27

what is the ratio of osteoid to osteomalacia?

Answer 27

osteoid that doesn’t become mineralized with hydroxyapetite

Question 28

Describe the clinical presentation of osteomalacia?

Answer 28

bone pain, local tenderness, fractures

Question 29

What are pseudofractures associated with?

Answer 29

osteomalacia

consists of osteomalacic bone

Question 30

what is hall mark of intrinsic bone diseases?

Answer 30

do not present with serum calcium abnormalities

Question 31

What is osteoporosis?

Answer 31

normal calcium and bone
- NOT ENOUGH BONE

-Labs: Normal calcium and phosphate

Question 32

What is the osteoporosis level?

Answer 32

2. 5 standard deviation below normal level

2. 5 t-score on a text scale

Question 33

What is osteoporosis?

Answer 33

normal calcium and bone
- NOT ENOUGH BONE

-Labs: Normal calcium and phosphate

Question 34

Clinical presentation of post-menopausal osteoporosis?

Answer 34

distal radius and vertebral fractures

high turn over!!

Question 35

What type of bone is affected in PM OP?

Answer 35

trabecular bone

Question 36

presentation of AR-OR?

Answer 36

proximal femur fractures and vertebral fractures

low turn over!!

Question 37

Etiology of AR-OP?

Answer 37

uncoupling of osteoblasts and osteoclasts

with equal trabecular and cortical involvement

Question 38

Causes of secondary osteoporosis?

Answer 38

hyperthyroidism

-steroid-induced (inhibits osteoblast precursor)

Question 39

Causes of secondary osteoporosis?

Answer 39

• hyperthyroidism
• steroid-induced (inhibits osteoblast precursor)
• malignancies

Question 40

What is Osteogenesis imperfecta?

Answer 40

Disorder of bone formation

type 1 collagen defect —> multiple fractures

Question 41

Associated findings of OI?

Answer 41

Blue sclera, hearing loss, tooth abnormalitis

Question 42

Causes of osteopetrosis?

Answer 42

Resorption disorder–> osteoclast failure

Adult form- dominant
kids- recessive

Question 43

Osteoporisis buzzword?

Answer 43

erlenmeyer flask

Question 44

Cause of Pagets?

Answer 44

Disorder of bone remodeling – > high bone turnover from increased osteoclast function

Question 45

Paget clinical?

Answer 45

high output HF, bone pain, arthritis