Master the board step 3

Master the Boards: USMLE Step 3
Diagnostic Testing
The best initial test is x-ray of the joint.
For CCS, all of the following should be ordered; there is no specific diagnostic test:
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ANA
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ESR
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Rheumatoid factor
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Anti-CCP
All other inflammatory markers will be normal. Joint fluid will have a low
leukocyte count < 2,000/mm 3 .
Treatment
Treatment is with acetaminophen. Chondroitin sulfate is not clearly useful to
slow joint deterioration. Weight loss and exercise help.
The following table compares osteoarthritis with rheumatoid arthritis.
Glucosamine is a wrong
answer. Glucosamine =
placebo
OA
RA
Morning stiffness < 30 minutes > 1 hour
DIP Yes No
PIP Yes Yes
MCP No Yes
RF, anti-CCP No Yes
Joint fluid leukocyte count < 2,000 5,000–50,000
• Rash + Joint pain +
Fatigue = Lupus
Systemic Lupus Erythematosus (SLE)
As shown in the following table, there are 11 criteria for lupus; 4 are needed
to confirm the diagnosis.
142