Pleural Effusion-Exudate

Etiology

Infection

Viral

Bacterial

Fungal

Parasitic

Neoplasm

Rheumatologic

Gastroenterologic

Cardiac

Renal

Reproductive

  • Ovarian Hyperstimulation Syndrome (see Ovarian Hyperstimulation Syndrome, [[Ovarian Hyperstimulation Syndrome]])
  • Pregnancy (see Pregnancy, [[Pregnancy]]): small amounts of U/S-detected pleural effusion are a normal finding in pregnancy (unclear whether these are transudates or exudates)
  • Meig’s Syndrome (see Meig’s Syndrome, [[Meigs Syndrome]])
  • Endometriosis (see Endometriosis, [[Endometriosis]])

Drugs

Other


Diagnosis-Pleural Fluid Criteria (see Pleural Effusion-General, [[Pleural Effusion-General]])

General Comments

  • LDH Ratio and Total Protein Ratio are Necessary from Light’s Criteria
    • The pleural LDH <66% criterion does not add more in discriminative value
  • Cut-Off Values for LDH and Total Protein Ratios: since there is not a discrete cut-off between values of LDH and total protein, the specified cut-off values give high sensitivity but lower specificity (ie: you will detect all true exudates, but you may misclassify some transudates as exudates, as in diuresed congestive heart failure cases)

Transudate (see Pleural Effusion-Transudate, [[Pleural Effusion-Transudate]])

  • LDH Ratio <0.6
  • Total Protein Ratio <0.5
  • Pleural LDH <66% of Upper Limit of Normal Range for Serum LDH
  • Pleural Cholesterol <55-60 mg/L
  • Pleural/Serum Cholesterol Ratio: normal
  • Serum-Pleural Albumin Gradient (SPAG) >1.2 g/dL
    • If fluid clinically appears to be a transudate and SPAG >1.2, but Light’s criteria suggest exudate, fluid can be assumed to be a transudate (albumin is lower MW than other proteins and crosses capillary walls more easily)

Exudate (see Pleural Effusion-Exudate, [[Pleural Effusion-Exudate]])

  • General Comments: pleural effusion is considered exudative if it meets any one of the following criteria, although LDH ratio and total protein ratio are the best criteria
  • LDH Ratio >0.6
  • Total Protein Ratio >0.5
  • Pleural LDH >66% of Upper Limit of Normal Range for Serum LDH
  • Pleural Cholesterol >55-60 mg/dL
  • Pleural/Serum Cholesterol Ratio: elevated
  • Serum-Pleural Albumin Gradient (SPAG) <1.2 g/dl
    • If fluid clinically appears to be a transudate and SPAG >1.2, but Light’s criteria suggest exudate, fluid can be assumed to be a transudate (albumin is lower molecular weight than other proteins and crosses capillary walls more easily)

References

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