Bone Pathology Flashcards

1
Q

What is the term for demineralization of bone seen on x-ray?

A

osteopenia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the 4 main causes of osteopenia? Which is most common?

A

osteoporosis is most common

osteomalacia

malignancy

rare hereditary disorders

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Are neoplasms involving bone usually primary neoplasms or metastases?

A

metastases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is a pathological fracture?

A

a fracture thorugh diseased bones - usually refers to a fracture through tumorous or tumor-like bone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How do the growth plates close in puberty?

A

sex hormones signal blood vessel incursion through the cartilage, which causes it to mineralize and the plate closes.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How much of the total body calcium is in bone?

A

99 percet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Low serum calcium levels will trigger secretion of what hormone to induce calcium release from the skeleton?

A

parathyroid hormone - triggers osteoblasts to activate the osteoclasts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Why is VItamine D such an important molecule for the skeleton?

A

It helps get calcium from the gut into the blood so that bone mineralization can occur

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Whta needs to happen to vitamin D before it can be useful?

A

It needs to by hydrosylated twice - first in th eliver and then in the kidney in the presence of PTH.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What molecule will inhibit the hydroxylation of vitamin D?

A

phosphate

and vit D(OH2) itself

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is unique about the blood clot that forms in fractures?

A

It will become fibrous like other blood clots, but then it will mineralize!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What reaction will the periosteum have in response to bone trauma?

A

It will lay down new bone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are some complications of fractures thorugh healthy bone?

A

mal-alignment

non-union / pseudoarthrosis

osteomyalitis (especially in compound fractures)

growth disturbance (in kids)

arthritis (if fracture is intraarticular)

fat embolism syndrome

PE - from immobilization

Osteoporosis of immovilized bone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what is osteoporosis?

A

a type of osteopenia due to bone atrophy caused by an imbalance of the bone remodeling process - more osteoclast activity than osteoblast

its definitely age related, and much more in women

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the clinical manifestations of osteoporosis?

A

pretty much asymptomatic until they get a fracture

vertebral fractures are the most common:

compression fractures (pancake fractures) are acutely painful, while wedge fractures (more common) are usually painless and just cause them to slowly stoop and shorten

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are some causes of osteoporosis?

A

low estrogen postmenopause

excess corticosteroids

hyperparathyroidism

hyperthyroidism

poor nutrtiion or malabsorption

immobilization

hypogonadism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

WHy should you keep osteoporosis as a diagnosis of exclusion?

A

Becuase there are causes of secondary osteoporosis which are much more treatable and even reversible

osteopenia does NOT = osteoporosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

In osteopenia, is it the compact or cancellous bone that really demineralizes?

A

the cancellous bone.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Why do you get kyphosis in severe osteopenia?

A

You get wedge fractures of the anterior vertebral bodies under the weight of the head.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Besides the spine, what are some bones that are commonly affected by osteoporosis?

A

any bone that’s near key stress joints like the proximal femur, proximal humerus and distal radius

it will NOT take much force to break these

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is the best prevention for osteoporosis?

A

maximize peak bone mass in young adulthood and encourage weight bearing exercise and Ca and Vit D supplementation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is the strongest predictor of ostoporosis risk?

A

maternal hip fracture

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is the actual way to diagnose osteoporosis - not an x-ray after a fracture?

A

bone densitometry

diagnose if they are under 2.5 deviations of the average for a yount adult

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Most anti-osteroporosis meds inhibit what?

A

osteoclast bone resorption

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Hypercalcemia is almost always due to what?
a primary hyperplasia or neoplastic enlargment of the parathyroid glands
26
Which type of bone is more resorbed in hyperparathyroidism - trabecular or cortical?
cortical
27
What are some complications of primary hyperparathyroidism?
fractures due to demineralization metabolic impariment of the kidneys and renal stone disease (because of the excess calcium) muscle weakness neuropsychiatric syndromes
28
In hyperparathyroidism you will see ___ serum calcium and ____ serum phosphorus.
elevated Ca and decreased P
29
What is osteomalacia?
It's decreased bone mineralization with **excess osteoid** due to an interference with calcium, phosphate, or vitamin D metabolism - sometimes hard to tell the difference it will be osteopenic on radiology
30
How is the presentation for osteomalacia different from that of osteoporosis? 1 important distinction...
osteomalacia can present with diffuse skeletal pain without fracture while osteoporosis will be asymptomatic until the fracture
31
What can cause osteomalacia?
1. rickets (environmental) 2. Intestinal malabsorption - commonest cause of Vit D deficiency in the US 3. Liver or renal disease - impaired hydrosylation of Vit D 4. Rare congenital errors of metabolism
32
What will labs show in osteomalacia?
increased serum alkaline phosphatase becuase the osteoblasts are trying to repair... low serum Ca or P decreased urinary Ca excretion Increased PTH - attempt at a compensatory mechanism decreased in hydrosylated vitamin D
33
What will a vitamin D deficiency in children (rickets) cause?
widened/shortened growth plates bowed legs due to softened bone fractures
34
What is "renal rickets"?
Renal osteodystrophy it's a progressive destruction of the second hydroxylation of Vitamin D in the kidneys most commonly a combination of secondary hyperparathyroidism and abnormal mineralization
35
Under histology, what is the hallmark of osteomalacia?
osteoid seams - the osteoid is layed down by the osteoblasts but doesn't mineralize
36
WHat is the primary mode of acquisition for an osteomyelitis in children? In adults? In diabetics?
kids: hematogenous spread to bone from an occult source adults: direct infection through compound fractures or orthopedic procedures diabetis: secondary infection through an adjacent contiguous infection like joint or soft tissue infections - usually feet
37
Which bones are most often affected by osteomyelitis?
long bones - usually starts in the metaphyseal region
38
How do you definitivly diagnose an osteomyelitis?
take a direct bone culture blood cultures will work too, but children may culture negative they'll also have fever, high WBCs and bone pain - the bone pain without acute injury is the big tip off
39
What is the most common microorganism for osteomyelitis?
staph auerus 95%! Some streptococcus, gram negative bacilli and salmonella in sick cell patients
40
Which radiological technique is better for catching an osteomyelitis?
MRI are better at early detection x-ray won't see it until about 10 days after it starts
41
WHat are some potential chronic complications of suppurative osteomyelitis?
suppurative arthrtis of the adjacent joints sinus tracks to skin - drianage growth disturbance in kids deformity amyloidosis - in any chronic inflamatory condition
42
What is the treatment for osteomyelitis?
aggressive! IV antibiotics can use surfical drainage/deridement amputation in chronic cases
43
What bones does TB usually spread to? WHat is this called?
spine and long bones if in the spine = Pott's disease
44
What are the two major fungi that can cause osteomyelitis?
blastomycosis is the most common in immunocompetent patients coccidioidomycosis always secondary to hematogenous spread form lungs
45
WHere in the long bones does osteomyelitis often start?
the metaphysis
46
Where do spinal osteomyelitises start?
hematogenous spread directly into the disc, from there is goes into the disc above and below
47
What are the most common causes of avascular bone necrosis/infarction?
fractures is the big one corticosteroid Rx alcoholism
48
Which bone is most commonly affected by abascular necrosis?
femoral head
49
What is the difference between a subchondral infarct and a medullary infart?
subchondral infarcts are in the epiphyses and affect the joint - causing pain wtih activity medullary infarcts are infarcts of the shafts of bone and can be clinically silent unless they get very large (which they can) and cause fractures
50
What are the complications of avascular bone necrosis?
secondary degenerative joint disease bone growth deformities in kids pathologic fracture
51
What is Paget's Disease of bone (osteitis deformans)?
it's a deforming bone disease in middle aged ango-saxons due to a latent viral infection of osteoclasts in a genetically susceptible person usually makes large bones (skull, pelvis, tibia, etc) larger
52
What are the 3 phases of paget's disease of bone?
1. lytic: increased osteoclasts with bone resorption and increased vasculatiry 2. Mixed: increased osteoclast activity and increased osteoblast activity (as a componsation) 3. Sclerotic: increased osteoblastic phase - most characteristic radiologically
53
True or false: Paget's disease of bone causes widening slcerosis of the bone, and with that, a reduced risk of fractures.
False It does widen bones and make them bigger, but ironically it also makes the bones weaker and more likely to fracture
54
Paget's disease of bone is usually asymptomatic, but what are some symptoms that can occur?
principally pain due to fractures, compression of cranial nerves or spinal nerves or pain from secondary degenerative joint disease due to subchondral bone deformity sometimes the skin overlying an affected bone is warm during lytic/vascular phase
55
What lap finding will be significant in Paget's disease of bone?
increased serum alkaline phosphatase (without liver disease)
56
What are 4 major congenital bone disorders? Which are we most likely to see in our offices?
neural tube defects achondroplasia osteogenesis imperfecta - most common we'll see osteopetrosis
57
What is osteogenesis imperfecta a disorder of?
type 1 collagen synthesis - either abnormal or not enough as a result you have insufficient collagen for normal osteoid production and you get brittle bones and slow growth (causes osteopenia)
58
What is osteopetrosis a disorder of?
osteoclasts - they dont resorb bone normally so the bones get huge. the cure for this is a bone marrow transplant very rare
59
Using x-ray, bone tumors can be classified as either ___ or ______ or mixed.
osteolytic (demineralizing) osteoblastic (increased bone density)
60
What is the classic example of a purely osteolytic maligancy? How about a ostoblastic malignancy?
osteolytic = myeloma osteoblastic = metastatic prostate cancer
61
Metastatic tumors are the most common malignancies to bone. What are the most common source cancers?
lung breast and prostate but pretty much every malignant neopplasm is capable to metastasizing to bone
62
Which bones are the more common sites of mets?
larger bones but can be anywhere
63
What are the four hemic malignancies often affecting bone?
classic myeloma plasmacytoma lymphoma leukemia
64
What does plasmacytoma of bone (localized tumor of plasma cells) frequently evolve into?
classic myeloma
65
Most non-Hodgkins lymphomas involve bone as a secondary or primary lesion?
secondary
66
How do you diagnose myeloma on pathology?
blood smear shows huge ugly plasma cells
67
What are some clues on x-ray that a bone cancer is malignant?
areas of demineraization and hypermineralization - unable to draw a nice line around the areas penetrates the bone cortex infiltrates surrounding STs
68
Where do primary bone tumors most often arise?
metaphyses of long bones
69
What are the most common benign tumors of bone?
osteochondroma giant cell tumor chondroma osteoid osteoma fibroma (metaphyseal fibrous defect)
70
What are the most common malignant tumors of bone?
osteogenic sarcoma (osteosarcoma) chondrosarcoma lymphoma Ewing's sarcoma Chordoma
71
Which is the most common primary malignant tumor of bone in children and young adults? Middle aged and older adults?
young = osteosarcoma old = chondrosarcoma
72
Most benign cartilage tumors (chondromas) involves ___ bones while malignant cartilage tumors (chondrosarcomas) tend to involve ___ bones.
benign = small bones malignant = large bones
73
Malignant bone tumors tend to spread through blood or lymph?
blood
74
What is the commonest bone lesion?
metaphyseal fibrous defect - fibroma benign developmental defect found in a third of children - often regress spontaneously
75
What does an osteochondroma look like?
It's a bony stalk of bone with a cartilage cap basically, a piece of the epiphyseal frowth plate broke up and moved down to establish on the shaft. then ti started forming a new long bone.
76
Where do chondromas of bone usually occur?
in the small bone - particularly hands you'll see calcification on x-ray
77
If you have a kiddo with bone pain occurring at night that's relieved by aspirin, what is the likly diagnosis?
osteoid osteoma
78
Where do giant cell tumors occur in bone? Usually lytic or blastic?
epiphysis lytic - it's basically just huge osteoclasts
79
Osteogenic sarcoma prefers metaphyseal regions of large long bones, especially the...
knee
80
Osteogenic sarcoma may be secondary to.....3
paget's disease of bone prior irradiation old bone infarcts
81
Most sarcomas will metastasize to the....
lungs
82
CHondrosarcoma prefers large long bones and central skeleotn especially the....
pelvis
83
chondosarcoma has the world record for...
forming the largest tumors
84
What is the most aggressive/lethal of the primary bone tumors?
Ewing's sarcoma
85
Ewing's sarcoma affects what type of bone preferentially?
the DIAPHYSIS of long bones and flat bones of pelvis
86
Ewing sarcoma is composed fo small undifferentiated tumor cells known as...
primitive neuroectodermal neoplasm (PNET)
87