Bone Pathology - Witrak Flashcards Preview

Skin and Musculoskeletal - Week 5 > Bone Pathology - Witrak > Flashcards

Flashcards in Bone Pathology - Witrak Deck (44)
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1
Q

What is the leading cause of bone fractures in our country?

A

Osteoporosis

2
Q

What is osteopenia

A

Diffusely demineralized bone, can see on x-rays

Could be caused by:
Osteoporosis (usually the case)
Osteomalacia
Malignancy
Rare hereditary disorder (aka osteogenesis imperfecta)
3
Q

What is the most common type of tumor you see in the skeleton?

A

metastatic tumors from other sites

4
Q

What is a pathological fracture?

A

fracture through diseased bone (most often through tumorous bone)

5
Q

Which bone cells secrete alkaline phosphatase?

A

Osteoblasts

6
Q

What is sacrificed in the body in order to maintain ionized calcium at the right levels

A

Itegrity of the skeleton

7
Q

Source of Vitamin D?

A

Sunshine in skin

what you ingest

8
Q

What is required in order to have healthy bones?

A

In summary, for healthy bone:

Ca, P (from diet)
Vit D (from diet, skin synthesis)
gut (absorbing Ca, P, Vit D)
healthy kidney (makes Vit D (OH)2, resorbs/excretes Ca, P)
parathyroids (master gland for Ca, bone metabolism)

9
Q

What is a salter fracture?

A

Epiphyseal plate injury that could lead to growth disturbance

10
Q

What is fat embolism syndrome?

A

Usually occurs in people who have fractures. Fat travels to lungs and brain leading to shortness of breath, loss of consciousness, death…

11
Q

Ostepenia below the age of 50… what might be some of the differentials diagnoses you might predict???

A
Due to excess corticosteroids (endogenous or exogenous)
Hyperparathyroidism
Hyperthyroidism
Poor nutrition/malabsorption
Immobilization
Hypogonadism
Multiple other disease associations
12
Q

SEcondary problem due to kyphosis?

A

Poor ventilation due to hunch can lead to increased susceptibility of pneumonia

13
Q

Best prevention to osteoporosois

A

max peak bone mass (teen/young adults) nutrition and stuff

Encourage weight-bearing exercise and Ca supplemnetation

14
Q

What causes hypercalcemia?

A

primary hyperplasia or NEOPLASTIC enlargement of parathyroid glands

15
Q

How can kidney disease affect the skeleton?

A

Secondary hyperparathyroidism (renal disease) may also produce gross skeletal change.

16
Q

Classic indication of hyperparathyroidism?

A

Increase Ca and decreased Phosphorous

17
Q

Is increased calcium important to look into?

A

Yes, you need to find out the cause

90% of all cases due to malignancy and hyperparathyroidism

18
Q

Causes of osteomalacia:

A

Environmental: classic childhood rickets
Poor diet + sun exposure in northern latitudes

Intestinal malabsorption—commonest cause of Vit D deficiency in USA

Liver or renal disease (impaired hydroxylation of Vit D)

Rare congenital/inborn errors of metabolism

  • Deficient Vit D hydroxylation
  • Renal tubular phosphate leak
  • End organ resistance to Vit D (OH)2
19
Q

Difference in diagnosing osteoporosis and osteomalacia?

A

Osteomalacia has these signs:

Increased serum alkaline phosphatase (>90%)
Low serum Ca or P (50%)
Decreased urinary Ca excretion (33%)
Increased PTH (40%)
Decreased 1, 25 dihydroxyvitamin D3 (50%)

20
Q

Where does Vit D come from and where is it hydroxylated?

A

Vit D comes from diet and skin synthesis

It is first hydroxylated in the liver and then secondly in the kidney

In the kidney, it is PTH that stimulates the hydroxylation

21
Q

What stimulates secretion of PTH (parathyroid hormone)

A

Hypocalcemia

22
Q

How do PTH and Vit D affect the Ca levels in the intestine, kidney, bone and blood?

A

Kidney

  • PTH stimulates production of Vit D
  • PTH increases Resorbtion of Ca
  • PTH cause excretion of P

Bone
-Vit D and PTH stimulate transferring Ca from bone into the blood

Intestine
-PTH and Vit D stimulate increase in absorbtion of Ca and P from the intestine into the blood

23
Q

Why is osteoporosis so common in older women?

A
  • Ability of kidneys to hydroxylate Vit D(OH)1 to Vit D(OH)2 becomes impaired with age
  • Diminished PTH secretion by parathyroid glands in response to hypocalcemia
  • Increased osteoclastic activity
  • Decreased ability of osteoblasts to make matrix
24
Q

MOst common bacteria in suppurtative osteomyelitis?

A

Staph Aureus

25
Q

What fungi cause fungal osteomyelitis?

A

Blastomycosis and coccidioidomycosis:

Commonest causes of fungal osteomyelitis in non-immunosuppressed patients

Almost always 2° to hematogenous spread from lungs; original pulmonary infection may have gone undiagnosed or be asymptomatic

26
Q

Very painful location of osteomyelitis?

A

Vertebral osteomyelitis

27
Q

Sickle cell patients tend to get what kind of infection in their bones? (osteomyelitis)

A

Salmonella

28
Q

What it Paget’s Disease of bone?

A

Deforming bone disease of middle-aged to elderly adults

Current theory:
Due to a latent viral infection of osteoclasts in a genetically susceptible person
Affects up to 10-15% of elderly population (esp. Anglo-Saxon heritage)
Rare in Asians, Africa, India, Scandinavia

29
Q

What are the three phases of Paget’s disease?

A

Lytic— increased osteoclasts with bone resorption/increased vascularity
Mixed—Increased osteoclasts with increased osteoblasts, increased vascularity
Sclerotic—most characteristic radiologically (osteoblastic phase)

30
Q

What would you see in radiological images of Paget’s Disease?

A

Most patients asymptomatic
Widening / bowing of long bones
Distorted / widened pelvic bones
General weakening of affected bone causing increased fractures

31
Q

Biochemically, as a physician you would suspect Paget’s if:

A

Older patient
Isolated increased alkaline phosphatase level
Normal serum calcium
No hepatobiliary disease

32
Q

What is osteogenesis imperfecta?

A

Congenital disorders of type 1 collagen
Either qualitatively abnormal or quantitatively too little
Result:
-insufficient / inadequate collagen for normal osteoid production
- Osteopenia/osteoporosis
-tendency toward fractures

33
Q

What is osteopetrosis?

A

Thicken bone, a lot more osteoblast rather than osteoclast activity
Loss of balance
Thick and chalk-like, so big but still easy to break

34
Q

What can x-rays help to predict about tumours involving the bones?

A

Likelihood of primary vs metastatic lesion

Ability to subtype primary bone tumors by location and x-ray character

Usually accurate in separating benign from malignant lesions

By x-ray, tumors can be classified as either:

  • osteolytic (demineralizing effect)
  • osteoblastic (increased bone density relative to normal bone)
  • mixed osteolytic/osteoblastic features
35
Q

Example of purely osteolytic bone malignancy?

A

Myeloma

  • Multifocal osteolytic lesions with bone pain
  • Often associated hypercalcemia
  • Fractures common
36
Q

Example os purely osteoblastic bone malignancy?

A

metastatic prostate cancer

37
Q

Why can leukemia sometimes be misdiagnosed as childhood rheumatoid arthritis?

A

acute leukemia alsways involves the bone marrow

Can produce diffuse bone or joint pain when the lymphocytes enter the periosteum

pain that almost seems like rheumatoid arthritis

38
Q

What are bone fibromas?

A

CommonEST bone legion (not a neoplasm)

Can be found in 1/3 of growing children

Only a small fraction present clinically & need Rx
Pain

Pathologic fractures sometimes occur

Often spontaneously regress

39
Q

CommonEST primary malignant tumor in:
Children
AND
Adults

A

Children: Osteosarcoma
AND
Adults: Chondorsarcoma

40
Q

Abnormal thickening of the cortex of bones, usually long bones

A

osteoid osteoma

41
Q

What kinds of bones do benign vs malignant cartilage tumors tend to involve?

A

Chondromas - small bones

Chondrosarcomas - large bones

42
Q

epiphysis is targeted by this type of tumor

A

giant cell tumor

43
Q

The most aggressive/lethal of all primary bone tumors?

A

Ewing’s sarcoma!

44
Q

One thing I didn’t get: How does kidney disease even affect the skeleton?

A

Impaired kidneys lose the ability to remove phosphorus from the blood which causes serum phosphate levels to increase. Phosphorus is involved in the regulation of calcium, high blood levels of phosphorus cause calcium to drop. If calcium levels drop, the parathyroid glands in the neck secrete parathyroid hormone which pulls calcium from the bones to compensate. This gradually and silently weakens the bones.

Called renal osteodystrophy.