Pleural effusions can be caused by a mismatch between pleural fluid production and absorption from the capillaries of the parietal pleura or interstitial spaces of the lung. Exudative pleural effusions are suggested by LIGHTS criteria where the pleural fluid to serum ratio is above 0.5 for protein or 0.6 for LDH. Common causes of exudative effusions include bacterial pneumonia, tuberculosis, malignancy, and viral infections. Transudative effusions are commonly caused by left ventricular failure or cirrhosis. Invasive procedures are needed for pleural effusions if they are loculated, have a pH below 7.2, glucose below 60, or signs of infection.

1. Pleural Effusion

2. Cause of pleural effusion
❖ Mismatch between pleural fluid production and absorption
❖ Source - capillaries of parietal pleura
- interstitial spaces of lung via visceral pleura
- peritoneal cavity via holes in diaphragm

3. CRITERIAS
LIGHTS CRITERIA
★ Pleural fluid protein/Serum protein > 0.5
★ Pleural fluid LDH / Serum LDH > 0.6
★ Pleural Fluid LDH > ⅔ rd of normal upper limit of serum LDH
Atleast one criteria is suggestive of Exudative Pleural effusion……
Note- 25% of transudates are misidentified as exudate

4. Hence,
Serum protein - Pleural fluid protein > 3.1 gm/dl ……..EXUDATE IS RULED OUT.

5. TWO TEST
1. Pleural fluid cholestrol > 45 mg/dl
1. Pleural fluid LDH > 0.45 times the upper limit of serum LDH

6. THREE TEST
1. Pleural fluid cholestrol > 45 mg/dl
1. Pleural fluid LDH > 0.45 times the upper limit of serum LDH
1. Pleural fluid protein > 2.9 g/dl

7. Causes of Exudative Pleural Effusion
➔ Bacterial Pneumonia
➔ Tuberculosis
➔ Malignancy
➔ Viral infection
➔ Pulmonary Embolism

8. TRANSUDATIVE EFFUSION
1. Left Ventricular Failure
1. Cirrhosis

9. Important stuff
Pleural fluid NT pro BNP > 1500 pg/ml ---- Left Ventricular Failure
Pleural fluid ANA titres > 1:160 PLUS Pleural fluid ANA/Serum ANA >= 1 --- 92 %
sensitive for SLE.
Pleural fluid ADA > 40 IU/L ---- Tuberculosis
False negative ADA- Lymphoma, Leukemia, Collagen Vascular Diseases

10. Tubercular Pleural Effusion
Due to hypersensitivity reaction to tuberculosis protein in pleural space
Exudative, Lymphocytic
ADA> 40 IU/l
INF (Interferon)> 140 pg/ml

11. Malignant pleural effusion
Pleural fluid glucose < 60 mg/dl
75% - Lung Carcinoma, Breast carcinoma, Lymphoma
MESOTHELIOMA - Primary tumor of mesothelial cells, related to asbestos
exposure. PLEURAL EFFUSION, PLEURAL THICKENING, SHRUNKEN
HEMITHORAX

12. HEMOTHORAX
Hematocrit of pleural fluid>½ blood hematocrit
CHYLOTHORAX
Trauma/Tumor in mediastinum, Milky, Pleural fluid triglyceride > 110 mg/dl
Treatment- Chest tube + Ocreotide ; Pleuroperitoneal Shunt

13. Invasive procedure for Pleural Effusion if……..
★ Loculated effusion
★ Pleural fluid pH<7.2
★ Pleural fluid glucose < 60
★ Positive gram stain/culture
★ Gross pus in pleural space