Pleural effusion, Light's Criteria
Light's Criteria:
Exudates will have at least one of the following:
Pleural/Serum protein ratio >0.5.
Pleural/Serum LDH ratio >0.6
Pleural LDH >200 U/L (>2/3 upper limit of normal for a simultaneously taken Sr LDH.)
Thoracentesis can be performed safely in the absence of d/o of hemostasis, on effusions that extend >10 mm from the inner chest wall on a lateral decubitus film.
Pleural effusion - causes:
Transudates: Usually bilateral on CXR
CHF
Cirrhosis with ascites
Nephrotic syndrome, renal failure
Exudates: Usually unilateral on CXR
Pneumonia
Parapneumonic effusion
Malignancy
PE: the only effusion which may be either exudative or transudative.
Collagen vascular disease
Pancreatitis
TB
Post-cardiac injury syndrome, chylothorax
Uremia
Esophageal perforation
Mesothelioma
Viral infection
sarcoidosis
yellow-nail syndrome
myxedema
urinothorax.
Orders: 4 tubes.
Tube 1: LDH, Protein, Glucose, Amylase, TG
Tube 2: GS, C&S, Fungal C&S, AFB
Tube 3: Cell count, diff
Tube 4: Cytology, pH, Adenosine deaminase (TB)
Transudate:
WBC <100/mm3; and RBC <10,000/mm3
Pleural fluid pH is > than Sr. pH
Pleural fluid glucose = serum glucose
Exudate:
Sr. albumin - Pleural albumin. If it is <1.2 mg/dL, then effusion is exudates.
Bloody pleural fluid = malignancy, PE, or trauma
Hemothorax: pleural fluid Hct : Serum Hct ratio >0.5 (50%). Insert Chest tube.
Eosinophilia >10% suggest air or blood in pleural space; fungal, parasitic inf; drug induced; PE; asbestos related; or Churg-Strauss syndrome.
Lymphocytes >50% = TB or malignancy.
Plasma cells = multiple myeloma
Mesothelial cells = not likely to be TB, likely mesothelioma.
LDH is indicator of pleural inflammation
Glucose <60 mg/dL - TB, cancer, RA, parapneumonic effusion
If glu <40 - insert CT.
pH <7.3 - Empyema, TB, cancer, collagen vascular dz, esophageal rupture
Empyema needs drainage (CT or VATS).
Amylase (salivary) - pancreatic dz, cancer, esophageal rupture.
Chylothx: TG >110 mg/dL, turbid. Also in lymphoma.
When the pt has lymphocytic pleocytosis in pleural fluid, suspect TB even if there are negative sputum stains for AFB.
Cytology +ve in 60% of malignant pleural effusions. Collect in fluid collection bag that is primed with Heparin, 1000 IU.