Acd 7 15-14: Pleural effusion
-
Upload
nick-gowen -
Category
Health & Medicine
-
view
474 -
download
0
description
Transcript of Acd 7 15-14: Pleural effusion
ACD
Will Atchley
Pleural effusion
• Indications for thoracentesis:– Any new effusion identified by chest imaging– 2 situation when not required:• Small effusion with clinically obvious etiology (e.g.,
pleurisy) – can observe– Effusions < 1 cm between pleural line and chest wall
• Clinically obvious HF– Unless: bl effusions different sizes, doesn’t respond to HF trt,
fever or pleurisy
Pleural effusion
• Contraindications to thoracentesis:– No absolute, need risk:benefit analysis– Caution: anticoagulation, plts < 50k, Cr >6
• Fluid studies:– cell count, pH, protein, lactate dehydrogenase,
glucose, amylase, gram stain, culture, and cytology.
Light’s criteria
• To classify effusion as exudate: – Only need 1 of the following:
• Pleural fluid protein/serum protein ratio greater than 0.5, or• Pleural fluid LDH/serum LDH ratio greater than 0.6, or• Pleural fluid LDH greater than two-thirds the upper limits of the
laboratory's normal serum LDH
Pearls on Effusions/fluid analysis• Uncomplicated parapneumonic effusions and effusions from pulmonary
embolism, TB pleurisy, and postcardiac injury syndrome may persist for several weeks.
• Benign asbestos pleural effusion, rheumatoid pleurisy, and radiation pleuritis often persist for months to years.
• A pleural fluid glucose conc < 60 mg/dl or pleural fluid/serum glucose less than 0.5 narrows the differential dx:– rheumatoid pleurisy, TB pleurisy or other infection, lupus pleuritis, malignant
effusion, and esophageal rupture.
• asbestos effusions are usually unilateral, exudative, and about a third have an elevated pleural eosinophil count
• Transudative pleural fluid from patients receiving diuretic therapy may have an elevated protein level and be mistakenly classified as an exudate.– The NTproBNP level in the pleural fluid, especially if higher than
1500pg/mL, can be used to determine if the pleural fluid is a transudate– If NTproBNP is unavailable, can call a transudate if the total protein gradient
(serum minus pleural fluid) is greater than 3.1 g/dL in a patient with convincing clinical picture of HF who is taking diuretics
• In a lymphocytic effusion, further investigation should be considered for TB, sarcoidosis, lymphoma, chylothorax, and pseudochylothorax
• Pleural biopsy typically follows CT scan in undiagnosed pleural effusions.
Pearls on Effusions/fluid analysis
TB effusions• In a lymphocytic effusion, further investigation should be considered for TB,
sarcoidosis, lymphoma, chylothorax, and pseudochylothorax– TB can be neutrophil predominant
• Virtually always have total protein concentrations above 4.0 g/dL (40 g/L)
• Pleural fluid adenosine deaminase and IF-gamma increase likihood that lymphocytic effusion is due to TB – ADA: >45 to 60 U/L is 100% sensitive and ~97% specific– IF-gamma: >140 pg/mL is 94% sensitive and 92% specific
• Elevated levels of pleural fluid ADA and IF-gamma increase the likelihood that a lymphocytic effusion is due to TB.
• Empiric treatment for TB may be considered in selected PPD positive patients with an undiagnosed, lymphocyte-predominant exudate and no alternative likely etiology.
TB effusions• TB pleural effusion accounts for ~5% of disease due to Mycobacterium TB and is
the 2nd most common form of extrapulmonary TB after lymphatic involvement
• Usually self-limited and resolve spontaneously with or without treatment. Can potentially progress and become a TB empyema.
• Pleural fluid Cx’s positive typically ~30% cases.– Adding a pleural biopsy Cx can increase the yield to >90 percent
• NAA tests are relatively low sensitivity (62%) but high specificity (98%) for diagnosis of TB pleural effusions
• Sputum Cx is positive in 20-50% of patients with pleural effusion– Much more likely if pt also has concomitant parenchymal disease
Treatment of TB effusions
• Presumptive therapy is warranted for patients with lymphocytic exudate and a positive tuberculin skin test of IFN-gamma release assay, even in the absence of definitive diagnosis
• In the absence of treatment for TB pleuritis, patients have a 65% risk of developing pulmonary or extra-pulmonary TB within five years
• Treatment of TB effusion is similar to treatment of active pulmonary tuberculosis (TB)