Systems Pathology Exam 1

Diaphysis is the ___ of the bone

shaft

Metaphysis is the ___ of the bone

neck

Epiphysis is the ___ of the bone

end

What are osteocytes?

mature bone cells

What are osteoblasts?

bone forming cells

What are osteoclasts?

bone reasorbing cells

What allows for osteoclast activation?

Osteoclast precursor requires binding of RANK ligand from osteoblast

What is dysostosis?

developmental anomaly of bone (congenital)

localized abnormality

What is klippel-feil syndrome?

congenital fusion of 2+ cervical vertebra

Affects childern

What is the companion syndrome with klippel-feil syndrome?

Sprengel’s deformity- congenitally fused scapula

What is type one congenital kyphosis?

failed development

severe deformity

What is type two congenital kyphosis?

Failed segmentation

mild compared to type 1

What is dysplasia?

mutations interfere with growth and bone remodeling

What is cleidocranial dysplasia?

absent/under-developed clavicles

this can be caused by mutated transcription factor

What is achondroplasia?

dwarfism

leads to shortened long bones

What can be complications of achondroplasia?

increased odds of having stenosis of foramen magnum

spinal stenosis (lumbar spinal canal)

What is a companion syndrome that may be present with achondroplasia?

trident hand

What causes achondroplasia?

inhibited endochondral growth

mutated FGFR3

T/F Thanatophoric dwarfism is compatible with life

False- fatal

What is osteogenesis imperfecta?

“brittle bone syndrome”

Type 1 collagen disease (altered type 1 collagen)

Which type of osteogenesis is compatible with life vs lethal in utero?

Type 1= normal lifespan

Type 2= lethal in utero

What are some key characteristics of osteogenesis imperfecta?

Blue sclerae- translucent

Zebra-stripe sign

HVLA is contraindicated

What is radiolucent?

areas appearing darker on x-ray

due to lower density of structure

Ex: cartilage

What is radiopaque/radiodensity?

areas appearing brighter/whiter on x-ray

due to higher density of structure

Ex: bone, metal

What is osteopetrosis?

“marble bone disease”

dramatic increase in density of bone (skeletal sclerosis)

deranged hematopoiesis

What are some companion features of osteoporosis?

1. Chalk-stick pathological fracture

2. Erlenmeyer flask deformity

What causes osteopetrosis?

decreased osteoclast activity

Most frequently impaired acid production in osteoclasts

inability to remodel and resorb bone

What is osteoporosis?

Acquired severe loss of bone density and mass

increased risk of bone fracture

What is osteopenia?

milder loss of bone density and mass

What bone is primarily impacted by osteoporosis?

trabecular bone

What does a DEXA scan measure?

bone mineral density

What deviation would indicate osteoporosis vs osteopenia?

Osteoporosis= greater than 2.5

Osteopenia= between 1-2.5

What is a T-score?

DEXA compared to peak bone mineral density

What is a Z-score?

DEXA compared to age and gender matched BMD

Who is at risk for osteoporosis?Why?

1. Senile- decreased growth factor= decreased osteoblast activity

2. Postmenopausal- decreased estrogen= increased osteoclast activity

What are some consequences of osteoporosis?

1. Vertebral body compression

2. Femoral neck fracture

Osteoporosis can’t be diagnosed by x-rays until there’s ___ of bone mass lost

30-40%

What is rickets?

undermineralized bone linked to vitamin D deficiency

poor growth plates which affects childern

What is osteomalacia?

undermineralized bone due to Vitamin Deficiency

found in adults

What is primary hyperparathyroidism?

MC from an adenoma

increased osteoclast activity

increased renal tubule resorption of CA+

MC affects post-menopausal females

What are some consequences of hyperparathyroidism (primary)?

kidney stones (MC), bone pain

“painful bones, renal stones, abdominal groans,and psychic moans”

What is a companion features with hyperparathyroidism?

salt and pepper skull

rugger-jersey spine

subperiosteal resorption

What is a skeletal feature of advanced hyperparathyroidism?

Osteitis Fibrosa Cystica

What is paget disease?

disoredered bone remodeling of the axial skeleton or pelvis

Thick, but weak bone, “shaggy” appearance

chalkstick fractures/ mosaic pattern

What is a companion feature of paget disease?

Ivory Vertebra sign

What are the stages of paget diease of bone?

1. Regional osteoclastic activity

2. Osteoblastic activity

3. Sclerotic phase

Who is at risk for Paget disease?

Older caucasian males

Most have multiple sites

MC in axial skeleton/femur

What is a compound fracture?

open, skin is ruptured

What type of fracture is most common in kids?

incomplete

What is a comminuted fracture?

fragmented/splintered

What is a displaced fracture?

distal segment is misaligned

What is a stress fracture? How long does it take to heal?

microfractures

6-8 weeks

Where do Salter-Harris fractures occur?

in individuals with open growth plate

What is a type 1 salter-harris fracture?

fracture goes straight through the growth plate

“appears normal on x-ray”

What is a type 2 salter-harris fracture?

fracture extends through the growth plate and the metaphysis

What is the most common form of Salter-harris fracture?

Type 2 fracture

What is a type 3 salter-harris fracture?

fracture goes through the growth plate and epiphysis

Articular fracture

What is a type 4 salter-harris fracture?

fracture goes through the metaphysis, growth plate, and the epiphysis

articular fracture

What is a type 5 salter-harris fracture?

fracture occurs when there’s a crush injury to the growth plate

What is osteonecrosis?

ischemic necrosis of bone

asymptomatic or painful

What is the companion feature of osteonecrosis?

Osteochondritis Dissecans- subchondral bone has collapsed which causes cartilage to die

What can cause osteonecrosis?

1. mechanical trauma

2. thrombotic occlusion- long term corticosteroid use

3. Extravascular compression

What are the risk factors of Osteonecrosis? (TQ)

1. Vascular injury

2. Prolonged corticosteroid use

3. Systemic vacular pathology

4. Susceptibility to thrombosis

5. 25% idiopathic

What is legg-calve-perthes disease?

Pediatric avascular necrosis

results in mishappen femoral head

What is affected in childern with legg-calve-perthes disease?

reduced hip range of motion and pain

Abduction and internal rotation are most affected

What is osteomyelitis?

Bone marrow inflammation from an infection

acute (MC) or chronic (TB)

throbbing pain, fever

How does one get osteomyelitis infection?

Hematogenous (MC in children)

Adjacent infection (MC in adults)

What is the overall most common cause of osteomyelitis? (TQ)

Staphylococcus aureus (80-90%)

What is involucrum?

reactive bone around site of infection

What is sequestrum?

entrapped necrotic bone

What is draining sinus?

pus drains into surrounding soft tissues

What is the cause of chronic marrow infection?

Tuberculous

MC spread via hematogenous

Pott’s disease- TB can spread to spine

What is osteoarthritis?

degenration of articular cartilage

MC joint disorder- wear and tear

Cartilage breakdown

What is primary osteoarthritis?

insidious

MC form, adults, no significant trauma

age related

What is secondary osteoarthritis?

previous inury or deformity

trauma (obesity)

What are the common locations of osteoarthritis?

cervical and lumbar spine

knees and hips

What are the steps of cartilage breakdown with osteoarthritis?

1. Matrix cracks (fibrillation

2. Softens (chondromalacia)

3. exposes subchondral bone

T/F Inflammation drives osteoarthritis

False- may be present but doesn’t drive it

What are the advanced findings of osteoarthritis?

1. Exposed subchondral bone (eburnation)- bright white/ivory on edge of bone

2. Subchondral cyst- bone hitting bone (synovial fluid accumulate)

Symptoms of osteoarthritis

crepitus, worse in morning

severe osteophytes may impinge nerve roots

Where are Heberden’s nodes found?

DIP

Where are bouchard’s nodes found?

PIP

What is osteochondrosis?

group of disorders affecting growing bones and apophyses

What are some examples of osteochondrosis?

Scheuermann’s disease, Osgood-shlatter, and Legg-calve-perthes

What is osgood-schlatter disease?

Tibial Tuberosity Apophysitis

What is scheuermann’s disease?

Wedge shapped vertebrae

Endplate abnormalities

Increased kyphosis (5 degrees of anterior wedfing in 3 or more consecutive vertebral bodies

What is a companion feature of scheuermann’s disease?

Schmorl’s Nodes

What is rheumatoid arthritis?

Inflammatory, autoimmune disease

CD4+ T cells and macrophages (tumor necrosis factor)

Increased collagensase and osteoclast activity

What can cause Rheumatoid arthritis?

1. Rehumatoid Factor

2. Anti-cyclic citrullinated peptides

What does Rheumatoid arthritis affect first?

small joints (hands, wrist)

What is the 3rd MC location of RA?

Atlantoaxial instability

What is pannus?

destructive inflammatory tissue

proliferation of synovial cells and inflammatory cells

What is the companion feature with rheumatoid arthritis?

Swan-neck deformity

Central slip rupture

Volar plate rupture

What is the main differences between RA vs OA?

RA- autoimmune, inflammatory, eventual ankylosis

OA- degenerative, not driven by inflammation, no ankylosis

Who is most at risk for rheumatoid arthritis?

MC women 30-50

What is felty syndrome is a combination of what three things?

1. Rheumatoid arthritis

2. Neutropenia (recurrent infections)

3. Splenomegaly

What is Caplan syndrome a combination of?

1. Rheumatoid arthritis

2. Penumoconiosis (group of lung conditions)

What is juvenile idiopathic arthritis?

autoimmunity of multiple tissues (16 or younger with 6+ weeks of pain present)

Negative for RF, but positive IL-6 involvement

When is juvenile idiopathic arthritis most common?

age 1-3

What is seronegative spondyloarthropathies?

autoimmune attack on the spinal and axial skeleton joints

RF negative

HLA-B27 positive