ESR affected by:
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Gender
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age
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pregnancy
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Temperature
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Drugs (steroids, asalicylates)
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smoking
Severity and CRP:
10-40: mild inflammation, viral or bacterial infection
40-100: moderate inflammation viral or bacterial
100-200 marked inflammation, bacterial
>200: severe bacterial infection, vasculitis, severe arthritis
Infection
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CRP may be useful when considering undifferentiated infection
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if >100 then likelihood of bacterial infection greater compared to viral infection
Screening
- Neither CRP or ESR useful
Polymyalgia rheumatica
-
both CRP and ESR recommended
-
CRP reommended for monitoring
Giant cell arteritis
-
Cases with normal ESR and increase CRP reported
-
higher sensitivity for diagnosis
-
CRP monitoring
Rheumatoid arthritis
-
neither CRP nor ESR included in diagnostic criteria
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CRP for monitoring
Systemic lupus erythematosus
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lack of correlation between CRP and disease activity
-
distinguish between lupus flare and infection
-
normal in flare
-
increase in infection
-
ESR elevated in both
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Malignancy
- no role
Differentiate between bacterial and viral pneumonia
-
insufficient evidence
-
van der Meer et al.
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systematic reveiw
-
poor quality
-
not sensitive nor specific to rule in infiltrate and bacterial aetiology
-
not enough high quality studies so cannot be sure
- van der Meer V, Neven AK, van den Broek PJ et al. Diagnostic value of C reactive protein in infections of the lower respiratory tract: Systematic review. BMJ 2005;331:26-9.
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HsCRP and CVRA
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CRP is consistently, although weakly, associated with CVD
-
does’t add enough to recommend routine adoption for populaiton screening