Symptoms and signs of disease:
-Inflammation of the parietal pleura leads to pain
-Dyspnea, cough.
-Chest examination: dullness to percussion, decreased or absent tactile fremitus and decreased breath sounds.
Laboratory and imaging studies:
1)Chest radiography: blunting of the costophrenic angle or opacification of the base of the hemithorax without loss of volume of the hemithorax
2) Thoracentesis: in the absence of disorders of hemostasis, on effusions that extend >10 mm from the inner chest wall on a lateral decubitus film.
3) Pleural fluid analysis: no Light’s criteria:
-pleural fluid protein/serum protein >0.5
-pleural fluid LDH/serum LDH >0.6
-pleural fluid LDH more than two-thirds normal upper limit for serum
A serum-to-pleural fluid albumin gradient of >1.2 g/dL: the pleural fluid is likely due to congestive heart failure, liver disease, or kidney disease.
*The most common cause: left ventricular failure. The effusion occurs because the increased amounts of fluid in the lung interstitial spaces exit in part across the visceral pleura.
+A diagnostic thoracentesis: performed:
-If the effusions are not bilateral and comparable in size, if the patient is febrile, or if the patient has pleuritic chest pain.
-If the effusion persists despite diuretic therapy
+A pleural fluid N-terminal pro-brain natriuretic peptide (NT-proBNP) >1500 pg/mL is virtually diagnostic of an effusion secondary to congestive heart failure
*Cirrhosis and ascites: the direct movement of peritoneal fluid through small openings in the diaphragm into the pleural space.