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Pleural Effusion 2178


  1. A pleural effusion is fluid in the pleural space.
  2. Effusions can be divided by their protein concentration into transudates (<3gm%) and exudates (>3gm%).
  3. Blood in the pleural space is a hemothorax; pus in the pleural space is an empyema, and chyle (lymph with fat) is a chylothorax.
  4. Both blood and air in the pleural space is called a hemopneumothorax. 

Causes (Ref. Hari. 18th ed., Pg-2180, Table 263.1)


Transudates may be due to

  1. Increase venous pressure (cardiac failure, constrictive pericarditis, fluid overload),
  2. Hypoproteinemia (cirrhosis, nephrotic syndrome malabsorption).
  3. Hypothyroidism 

Exudates due to increased leakiness of pleural capillaries secondary to infection, inflammation, or malignancy.


  1. Bacterial Pneumonia;
  2. TB;
  3. Pulmonary infarction;
  4. Rheumatoid arthritis;
  5. Bronchogenic carcinoma;
  6. SLE;
  7. Lymphoma;
  8. Mesothelioma;
  9. Lymphangitis carcinomatosis
  10. Viral
  11. Meigs' syndrome (right pleural effusion and ovarian fibroma).

Investigations (Ref. Hari. 18th ed., Table Pg- 2178)


Exudative pleural effusion has at least one of the following criteria

  1. Pleural fluid protein/ serum protein > 0.5
  2. Pleural fluid LDH/ serum LDH > 0.6
  3. Pleural fluid LDH > 2/3 of upper limit of normal for serum LDH.

Causes Of Left Sided Effusions

  1. Rheumatoid arthritis
  2. Pancreatitis
  3. Pericardial inflammation
  4. Esophageal rupture.
  5. Left sided subdiaphragmatic abscess
  6. Thoracic duct involvement above D5 level

Important Points: - Causes of Right Sided Effusions

  1. Fluid retaining states – CHF, CRF, Cirrhosis
  2. Amoebic liver abscess, subphrenic abscess
  3. Meig’s syndrome
  4. Thoracic duct involvement below D5 level.

Causes of B/L Effusion – LVF, Pulm infarction, Hypoalbuminemia, Malignancy.


Features of tubercular pleural effusion.

  1. All features of exudative effusion plus following.
  2. Hemorrhagic effusion
  3. Presence of high level of TB markers
    1. ADA > 45
    2. Interferon γ > 140 pg/ml
    3. Positive PCR
  4. Glucose level equal to serum level mostly, occasionally <60 mg%
  5. WBC , predominantly small lymphocyte.
Extra Edge:

Presence of mesothelial cells > 5% make diagnosis of tubercular effusion unlikely.


Important Points: - Pleural Effusion in AIDS – causes

  1. Kaposi sarcoma       
  2. Tuberculosis
  3. Lymphoma  
  4. Parapneumonic effusion  
  5. Cryptococcosis 

Glucose < 60mg/dl seen in -


Definite condition associated with Glucose < 60mg%

  1. Parapneumonic effusion                      
  2. Malignant disease               
  3. Rheumatoid arthritis
Extra Edge

In Tubercular effusion, plural fluid glucose level is usually is normal.


Important Points:


LDH – Indicator of degree of pleural inflammation


Pt’s who meet the diagnostic criteria of exudative pleural effusion with LDH but not with protein have  -      

  1. Parapneumonic effusion
  2. Malignant pleural disease 

Amylase – Increase levels seen in

  1. Pancreatitis                              
  2. Malignant tumor
  3. Esophageal rupture                  
  4. Ruptured ectopic pregnancy 

Important Points:  –  pH < 7.2 seen in

  1. Complicated parapneumonic effusion        
  2. Esophageal rupture              
  3. Rheumatoid disease             
  4. Tubercular pleuritis                  
  5. Malignancy                  
  6. Hemothorax
  7. SLE 

Chylothorax –

  1. Causes – Trauma, Tumour – lymphoma, tuberculosis, congenital absence of thoracic duct, yellow nail Syndrome, Filariasis
  2. Chylous fluid is milky and has a Triglyceride level >110mg/dl  


  1. In chronic effusion due to rheumatoid arthritis fluid rich in cholesterol mimicking chyle accumulates.
  2. Treatment of choice for chylothorax Pleuroperitoneal shunt.
  3. Tube thoracostomy is contraindicated.  

Hemothorax – Causes Trauma, malignancy & Pulm embolism.

Important Points:

WBC count - <1000/mm3 – Transudative,   >1000/mm3 – Exudative

Differential WBC count –

  1. Neutrophils –     
    1. Pneumonia,
    2. Pancreatitis,
    3. Pulm embolization,
    4. Subphrenic abscess.
  2. Eosinophils -      
    1. Asbestos related pleural effusion  
    2. Parasitic      
    3. Drugs          
    4. Churg Strauss
  3. Basophils – Leukemic pleural effusion
  4. Lymphocytes – Tuberculosis, Malignancy, Post CABG
  5. Mesothelial cells –      
    1. Present normally
    2. D/D – Malignant cells
    3. No mesothelial cells are seen in TB (expect pt with AIDS)
  6. Plasma cells – Multiple myeloma

Symptoms of pleural effusion: Asymptomatic- or dyspnea.


  1. Decreased expansion;
  2. Stony dull Q percussion note;
  3. Diminished breath sounds Q occur on the affected side.
  4. Tactile vocal fremitus and vocal resonance are decreased.
  5. Above the effusion, where lung is compressed, there may be bronchial breathing and aegophony Q (bleating character of vocal resonance) and bronchophony.
  6. With large: effusions there may be tracheal deviation Q away from the effusion.
  7. Decreased heart sounds are seen in left sided pleural effusion.
Important Point:

Horizontal fluid level & Succussion splash both are feature of hydropneumothorax.



  1. Ultrasound is useful in identifying the presence of pleural fluid and in guiding diagnostic or therapeutic aspiration.
    It is the best investigation for minimal plural effusion Q.
  2. Pleural biopsy: If pleural fluid analysis is inconclusive, consider parietal pleural biopsy with an Abrams' needle.

Management is of the underlying cause.

  1. Drainage If the effusion is symptomatic, drain it, repeatedly if necessary. Fluid is best removed slowly. It may be aspirated in the same way as a diagnostic tap, or using an intercostal drain.
Extra Edge:

Site of pleural effusion drainage is seventh intercostal space in mid-axillary line.


Important Points: -

  1. Pleurodesis with tetracycline Q, bleomycin Q, or talc Q may be helpful for recurrent effusions.
  2. Thoracoscopic talc pleurodesis is most effective for malignant effusion
Extra Edge   Drug-induced Pleural Disease
  1. Nitrofurantoin           
  2. Dantrolene           
  3. Methysergide                
  4. Bromocriptine
  5. Procarbazine             
  6. Amiodarone           
  7. ​Dasatinib

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