Term
| ANA (Antinuclear Antibodies) |
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Definition
• Autoantibodies directed against:
- Histones, dsDNA, RNA, ribonucleoproteins (RNP)
• Titer >1:40 considered positive • Pattern of staining not specific
- Except for centromeric pattern for limited scleroderma
• Screening test
- If positive test for specific nuclear antigens |
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Term
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Definition
Anti-ds DNA
• Against base pairs
• Common in SLE
-Specificity 97%
- Rare in other disorders
- Negative in most drug-induced lupus
Do not order with negative ANA
Anti-Sm and RNP
• Sm and RNP are extractable nuclear antigens
• Anti-Sm highly specific for SLE, only noted in 30–40% of cases
• Anti-RNP noted in SLE or MCTD
- Presence required for diagnosis of MCTD (mixed CT disease) |
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Term
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Definition
• Ro (Sjogren A or SS-A) and La (Sjogren B or SS-B)
- Order if considering Sjogrens, even if ANA (-)
• Distinct RNP particles.
• Anti-Ro
- Elevated in Sjogren syndrome and SLE
• Anti-La
- Elevated in Sjogren syndrome and SLE
- Also elevated in congential complete heart block (90%) |
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Term
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Definition
• Antibodies to centromere proteins
• Elevated in limited scleroderma,
scleroderma, and CREST
- CREST (calcinosis, Raynaud phenomenon, esophageal dysmotility, sclerodactyly, and telangiectasis)
• Very specific (98%) but not very sensitive (60%). |
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Term
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Definition
• Seen in scleroderma, rarely noted in other systemic rheumatic disorders
• Positive test very specific for scleroderma (100%)
• Sensitivity only 40% |
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Term
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Definition
• Noted in lupus induced by drugs
- Exception is minocycline-induced lupus
• Also noted in SLE
• Not helpful in separating SLE from drug-induced
lupus
• D/C drug and see if symptoms improve
• Drug-induced lupus
- Procainamide
- Hydralazine
- INH |
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Term
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Definition
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Term
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Definition
• Westergren is the gold standard • Why does it go up?
- Increase in acute phase reactants, excessive antibodies, age
• What is normal (for patients over 40)?
- Female—age/2 plus 5
- Male—age/2
• These are upper limits of normal |
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Term
| What to do with elevated sed rate? |
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Definition
- Malignancy?
• Rare, <5%
• Think bone mets or a monoclonal gammopathy
- Occult infection?
• Pneumonia, pyelonephritis
• Sneaky—SBE, bacterial discitis • Return to normal in 8–12 weeks
- Collagen vascular disease
• SLE, RA, polymyalgia rheumatica, temporal arteritis • Sneaky—vasculitis |
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Term
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Definition
• Autoantibody directed against Fc region of IgG
• Abnormal >1:40
• Noted in 70–90% of RA patients
- Many other disorders also have positive test • Including hepatitis C (can cause a viral arthritis)
• Interpret in conjunction with PE findings |
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Term
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Definition
- Cyclic citrullinated peptides
• Citrulline (an amino acid) is target of
autoantibody response
- Highly specific for RA
• Specificity 97%
• Maybe negative in early RA (only 50% positive) • Negative in hepatitis C |
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