My Clinical Notes

Causes

• Transudates;
  • May be due to increased venous pressure
    • Cardiac failure
    • Constrictive pericarditis
    • Fluid overload
    • Or hypoproteinaemia;
    • Cirrhosis
    • Nephrotic syndrome
    • Malabsorption
    • Can also occur in hypothyroidism and Meigs syndrome (right sided pleural effusion and ovarian fibroma)
• Exudates
  • Mostly due to increased leakiness or pulmonary capillaries secondary to;
    • Infection
    • Malignancy
    • Inflammation
  • Causes are;
    • Pneumonia
    • TB
    • Pulmonary infarction
    • RA/SLE
    • Bronchogenic malignancy
    • Malignant metastases
    • Lymphoma
    • Mesothelioma
    • Lymphangitis carcinomatosis

Signs

• Decreased expansion
• Stony dull percussion note
• Diminished breath sounds
• Reduced tactile vocal fremitus and vocal resonance
• Above the effusion where the lung may be compressed there may be bronchial breathing
• With large effusions there may be tracheal deviation away from the effusion
• Look for signs of associated disease;
  • Malignancy – clubbing, cachexia, lymphadenopathy, radiation scars
  • Chronic liver disease
  • Cardiac failure
  • Hypothyroidism
  • RA
  • SLE

Tests

• CXR – blunting of costophrenic angles, larger ones are seen as water dense shadows with a concave upper border (if flat upper border there is also a pneumothorax). 200ml is required to show up on a CXR
• Ultrasound
• Diagnostic aspiration
  • Chose a site 1-2 intercostal spaces below lower border of the pleural effusion
  • Infiltrate down to the pleura with 5-10ml of lidocaine 1%
  • Insert a 21G needle and syringe just above the upper border of the appropriate rub (avoids neuromuscular bundle), draw off 10-30ml
• Send for;
  • Clinical chemistry – protein, glucose, amylase, LDH, pH
  • Bacteriology – microscopy, culture, auramine stain, TB culture
  • Cytology
  • If indicated immunology – RhF, ANA, complement
• Pleural biopsy
  • With an Abram’s needle
  • Thoracoscopic or CT guided increased diagnostic yield

Light’s criteria for distinguishing pleural transudate from exudates

• Pleural fluid is an exudates if one of more of the following criteria are met;
  • Pleural fluid protein:serum protein ratio >0.5
  • Pleural fluid LDH:serum LDH ratio >0.6
  • Pleural fluid LDH is >2/3 of the upper limit of normal serum LDH

Management

• Drainage – drain slowly <2L/24hr
• Pleurodesis – with tetracyclin, bleomycin or talc may be helpful for recurrent pleural effusions
• Surgery – persistent collections and increasing pleural thickness

This entry was posted on Wednesday, January 14th, 2009 at 5:02 pm and is filed under Respiratory. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.