MSK System - Schoenwald (Exam 2) Flashcards
Osteoporosis is caused by (increased/decreased) bone (resorption/deposition).
Osteoporosis is caused by increased bone resorption.
What are the 2 types of primary osteoporosis?
For each type, what is the cause (increased osteoclastic activity vs decreased osteoblastic activity)?
-
Type 1: Postmenopausal (estrogen loss)
- Increased osteoclastic activity
-
Type 2: Senile
- Decreased osteoblastic activity
MC bones fractured in primary osteoporosis?
- Hip
- Compression fx of vertebrae
- Distal radius (FOOSH)
What are some causes of secondary osteoporosis?
- Endocrine: increased parathyroid hormone, DM, Addison’s dz
- Gastrointestinal: malnutrition
- Hematologic: blood cancers
- Drugs: long term prednisone usage, heparin, someo chemo agents
Describe the typical osteoporosis pt
Thin, white, postmenopausal female with long-term hx of smoking.
What’s the difference between DEXA scan T score and Z score?
- T score: Compares bone mass to healthy 30 yr old
- Z score: Compares to what’s normally expected for same age, sex, weight, and ethnic or racial origin
How does the T-score rating system work for DEXA scan?
- +1 to -1 = healthy bone density
- -1 to -2.5 = osteopenia
- -2.5 to -3.0 = osteoporosis
- -3.0 and lower = severe osteoporosis
What is an abnormal Z score (DEXA scan)?
-2 or lower
Rickets and osteomalacia are due to deficiencies in ___________ and ___________.
Vitamin D and phosphate
T/F: osteomalacia and rickets are due to decreased mineralization of osteoid while bone mass stays normal, resulting in bowing of legs
Truth
Difference between rickets and osteomalacia?
- Rickets: inadequate mineralization of osteoid matrix leads to overgrowth and distortion of epiphyseal cartilage
- Osteomalacia: affects newly formed bone matrix in adults
MC pathogen in osteomyelitis?
Staph aureus
T/F: Osteomyelitis due to hematogenous spread is more common in adults, whereas contiguous spread is more common in children
False.
Hematogenous spread more common in children. Contiguous spread more common in adults (think of an adult with a diabetic ulcer that gets infected and spreads to the bone - probably doesn’t happen very often in kiddos).
T/F: fever can be present with osteomyelitis but is often absent
Truth
Describe the pathology of osteomyelitis
- Infection lifts periosteum of bone, impairs blood flow, results in ischemia of bone
- “Sequestrum” = dead bone fragment
- “Involucrum” = new bone growth around sequestrum
- Brodie abscess = residual abscess surrounded by bone growth
What is the most common degenerative joint disease in age >65?
Osteoarthritis - progressive loss of cartilage at the joint space
Describe the pathology of osteoarthritis
- Microscopic findings: loss of proteoglycans and chondrocytes
- Fibrillation & splitting of cartilage surface - allows for synovial fluid infiltration = inflammation
- Granulation tissue and fibrosis replace cartilage = erosion of bony surface
- Osteophyte formation - reactive new bone - limit ROM of joint
What are the 2 types of osteophytes associated with osteoarthritis?
- Heberden node: DIP joint
- Bouchard node: PIP joint
Wellsian pro tip: B comes before H in the alphabet, so Bouchard nodes are more proximal
T/F: With osteoarthritis, morning stiffness usually resolves 30 minutes after waking
True
Radiologic findings in osteoarthritis include….
- Joint space narrowing
- Subchondral sclerosis and cysts
- synovial fluid leaks into defects in cartilage
- Osteophytes
What are some common bugs that cause infectious arthritis?
- Staph
- Neisseria gonorrhea
-
Chlamydia - reactive arthritis (Reiter’s syndrome)
- affects joints, eyes, and urethra
- Strep pneumoniae
Which statement is false regarding rheumatoid arthritis?
a. Morning stiffness for <30 minutes
b. 3 or more affected joints
c. constitutional sx of fever, wt loss, and fatigue may be present
d. all of the above are true
a.
Morning stiffness lasts >1 hour
Swan neck deformity, dupuytren’s contracture, and boutonniere deformity are all associated with which type of arthritis?
Rheumatoid arthritis
There is a triad for RA and it has a specific name. What is it?
Felty syndrome:
- RA
- Leukopenia
- Splenomegaly
Swan neck deformity = (flexion/extension) of PIP and (flexion/extension) of DIP
Swan neck deformity = _hyperextension_PIP and _flexion_ DIP
Boutonniere deformity = (flexed/extended) PIP and (flexed/extended) DIP
Boutonniere deformity = flexed PIP and extended DIP
Common joints affected by RA?
MCP, PIP, feet, ankles, knees, wrists, elbows
Common joints affected by OA?
Hips and knees, PIP and DIP
Morning stiffness lasts how long in OA?
<30 mins
Morning stiffness lasts how long in RA?
>1 hr
OA pain is (better/worse) with inactivity, whereas RA pain is (better/worse) with inactivity
OA pain is better with inactivity, whereas RA pain is worse with inactivity
90% of pts with ankylosing spondylitis are positive for ________
HLA B27
Ankylosing spondylitis preferentially involves which joints?
Vertebral column and SI joints
Gout is a form of arthritis due to _________ deposition in joint space
uric acid crystal
Risk factors for gout?
Alcohol, obesity, thiazide diuretics
In gout, urate crystals precipitate in the synovium and are a chemotactic for __________. They also activate ___________.
neutrophils and complement
What are tophi?
Aggregates of urates rimmed with macrophages, lymphocytes, and giant cells
- Found in joints and ligaments
- Can cause a chronic tophaceous arthritis
50% of first gout attacks occurat which joint?
1st MTP (aka Podagra)
Pseudogout is caused by what kind of crystals?
Calcium pyrophosphate crystals - rhomboid
Paget disease, aka ___________
osteitis deformans
Pathology of paget disease?
Excessive osteoblastic bone formation with abnormal structure and impaired stability
Clinical findings of paget disease?
- Enlargment of head bones
- HA
- Deafness
- Visual disturbances
- Deformation/tenderness of long bones
What would labs and imaging look like in Paget disease?
- Chalk stick fx = pathologic fx (cross fx of long bones)
- Thick coarse cortex of bone
- Elevated serum alk phos
What is the most common malignant bone tumor?
Osteosarcoma
XR with lytic lesions and codman triange = _________
osteosarcoma
Ewing sarcoma is often misdiagnosed as osteomyelitis because it often presents with ________and _______
fever and pain
XR shows bulky osteodestructive lesion with characteristic pattern of calcification-popcorn: __________
chondrosarcoma
Malignant fibrous histiocytoma is the most common sarcoma, affecting ____________, _____________, and ____________________________.
Deep fascia, skeletal muscle, and retroperitoneal space
Why did the bicycle go to bed early?
Because it was two tired
