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  #1  
Old 02-27-2011
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Arrow Test your knowledge #24! (Pathology)

A 17-year-old biracial female presents with an ulcer of the soft palate. The oral mucosa is erythmatous, and a rash is noted on her face and forearms. The patient tests positive for antinuclear (ANA), anti-dsDNA, anti-ribonuclear protein (RNP), anti-Ro, and anti-histone antibodies. Which of these is most strongly associated with the possibility of renal disease in this patient?
  1. antinuclear antibody
  2. anti-dsDNA antibody
  3. anti-RNP antibody
  4. anti-Ro antibody
  5. anti-histone antibody
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Old 02-27-2011
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I would go with
B. anti-dsDNA antibody
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Old 02-27-2011
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anti-ds dna suggestive of lupus nephritis
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I would go with B.anti-dsDNA
A.antinuclear antibody
Best screening test; repeated negative tests make SLE unlikelyanti-dsDNA antibody

B.anti-dsDNA antibody High titers are SLE-specific and in some patients correlate with disease activity, nephritis, vasculitis
C.anti-RNP antibody Not specific for SLE; high titers associated with syndromes that have overlap features of several rheumatic syndromes including SLE; more common in African Americans than Caucasians
D.anti-Ro antibody Not specific for SLE; associated with sicca syndrome, subacute cutaneous lupus, and neonatal lupus with congenital heart block; associated with decreased risk for nephritis
E.anti-histone antibody More frequent in drug-induced lupus than in SLE
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Old 02-27-2011
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Arrow SLE

SLE

Laboratory tests

Antinuclear antibody (ANA) - positive but not specific to SLE. ANA screening yields positive results in many connective tissue disorders and other autoimmune diseases, and may occur in normal individuals.

Subtypes of antinuclear antibodies include:

anti-Smith and anti-double stranded DNA (dsDNA) antibodies (which are linked to SLE)

anti-histone antibodies (which are linked to drug-induced lupus).

Anti-dsDNA antibodies are highly specific for SLE; they are present in 70% of cases, whereas they appear in only 0.5% of people without SLE.

SS-A (or anti-Ro) and SS-B (or anti-La) both of which are more common in Sjögren's syndrome

Lupus nephritis is an inflammation of the kidney caused by systemic lupus erythematosus (SLE), a disease of the immune system. Apart from the kidneys, SLE can also damage the skin, joints, nervous system and virtually any organ or system in the body.

The World Health Organization has divided lupus nephritis into five classes based on the biopsy. This classification was defined in 1982 and revised in 1995.

Class I is minimal mesangial glomerulonephritis which is histologically normal on light microscopy but with mesangial deposits on electron microscopy.

Class II is based on a finding of mesangial proliferative lupus nephritis. This form typically responds completely to treatment with corticosteroids.

Class III is focal proliferative nephritis and often successfully responds to treatment with high doses of corticosteroids.

Class IV is diffuse proliferative nephritis. This form is mainly treated with corticosteroids and immunosuppressant drugs.

Class V is membranous nephritis and is characterized by extreme edema and protein loss.

Test your knowledge #24! (Pathology)-lupus_facial_rash.jpg
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  #6  
Old 02-27-2011
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Ok totally off the track but that rash ruined such a pretty face!!!
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Old 02-27-2011
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Correct Answer Correct!

The answer is B. Anti-dsDNA antibody. The patient has SLE - the facial rash is probably the classical malar "butterfly" rash that spares the folds around the nostrils, especially on Step 1, but it might also be a discoid rash.

Test your knowledge #24! (Pathology)-lupus-discoid-childs-face.jpg
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Test your knowledge #24! (Pathology)-skin009.jpg
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Many autoantibodies may occur in patients with SLE and overlapping syndromes. This is adapted from Cecil's version of aktorque's list:
  • ANA - not specific to SLE, but >95% sensitive; a good screening test
  • Anti-Smith - very specific to SLE (99%)
  • Anti-dsDNA - associated with lupus nephritis (also anti-Sm and anti-C1q); we would want to measure C3 and C4 levels and get a UA and 24-hour urine protein in this patient.
  • Anti-ssDNA, anti-histone, anti-RNP, and anti-nucleoprotein are only moderately specific for SLE
  • Anti-Ro (SS-A) is seen in Sjögren's syndrome, SLE, primary photosensitivity, and primary biliary cirrhosis
  • Anti-La (SS-B) is seen in Sjögren's syndrome and SLE
  • Anti-RNP can be seen in SLE, RA, scleroderma, SS, and other mixed connective tissue diseases
source: Cecil's 7th ed.
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Quote:
Originally Posted by doctorsmonsters View Post
Ok totally off the track but that rash ruined such a pretty face!!!
Alright, less monster more doctor
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Old 02-28-2011
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I'd like to refer you guys to this thread
Positive Autoimmune Antibodies and Causes
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