Pleural Effusion and Pneumothorax: Detailed Information and Considerations

This document provides a comprehensive overview of pleural effusion (PE) and pneumothorax (PNX), covering their pathophysiology, diagnosis, treatment, and relevant considerations.

1. Pleural Fluid Physiology

• Normal Pleural Fluid: The pleural space normally contains a small volume of fluid (7-14ml) to allow for smooth movement of the lungs.
• Fluid Dynamics: Fluid is secreted by the parietal pleura and reabsorbed by the visceral pleura.
• Regulation: This process is regulated by factors like oncotic pressure (albumin levels), hydrostatic pressure (blood pressure), and negative pleural pressure.

2. Pathophysiology of Pleural Effusion (PE)

PE occurs when the balance between fluid production and absorption is disrupted, leading to fluid accumulation in the pleural space. Common causes include:

• Increased Capillary Permeability: This can be caused by infections, cancer, trauma, and other inflammatory conditions.
• Decreased Plasma Albumin: This can be caused by malnutrition, liver disease, nephrotic syndrome, and other conditions that lead to hypoalbuminemia.
• Increased Hydrostatic Pressure: This can be caused by heart failure, venous hypertension, and other conditions that increase blood pressure.
• Lymphatic Obstruction: This can be caused by tumors, inflammation, and other conditions that block lymphatic drainage.

3. Diagnosis of PE

Diagnosing PE involves identifying the following:

• Location: Is the effusion on the left or right side?
• Severity: Is it mild, moderate, or severe?
• Fluid Characteristics: Is it transudative (low protein) or exudative (high protein)?
• Underlying Cause: Is it due to tuberculosis (TB), cancer, pneumonia, or other conditions?
• Complications: Are there signs of dyspnea (shortness of breath), respiratory failure, or infection?

4. Types of Pleural Effusion

• Free Effusion: Fluid accumulates freely from the costophrenic angle upwards.
• Loculated Effusion: Fluid collects in specific locations:
  • Axillary effusion
  • Supra-diaphragmatic effusion
  • Mediastinal effusion
  • Interlobar effusion

5. Estimating Pleural Fluid Volume on Chest X-ray

• 100-250ml: Blurred costophrenic angle on lateral X-ray
• 250-500ml: Blurred costophrenic angle on frontal X-ray
• 1-1.5 liters: Lower 1/3 of the lung is obscured
• 2 liters: Half of the lung is obscured
• 3.5-4 liters: Entire lung is obscured

6. When Does Lung Collapse Occur with Thoracentesis?

The lung may not re-expand if there are underlying conditions, such as TB or cancer, that have caused fibrosis and lung contraction.

7. When to Suspect Exudative Effusion (Inflammatory)

• Unilateral or bilateral PE with significant differences in volume.
• Pleuritic chest pain (sharp, stabbing pain aggravated by breathing).
• Fever.

8. Common Causes of Exudative Pleural Effusion

• Lung Cancer (Primary or Metastatic): Rapid onset, large volume, rapid recurrence.
• Tuberculous Pleuritis: Slow onset, smaller volume, less frequent recurrence, past TB exposure history.
• Parapneumonic Effusion: Smaller volume, history of pneumonia (fever, cough, sputum, chest pain).

Important Note: PE typically does not cause chest pain, only tightness. If a patient experiences chest pain, consider pneumonia or pleuritis.

9. Important Tumor Markers to Remember

• Lung: Cyfra 21.1, CEA
• Gastrointestinal Tract: CEA
• Liver, Biliary, Pancreas: CA 19.9
• Liver: AFP
• Ovary: CA 125
• Breast: CA 15.3

Elevated levels of these markers suggest a primary tumor in the corresponding region.

10. Definitive Diagnosis of PE

• Clinical Examination: Dull percussion, decreased vocal fremitus, diminished breath sounds.
• Investigations: Chest X-ray, ultrasound, CT scan.
• Thoracentesis (Pleural Fluid Analysis): Determines fluid characteristics, looks for cancer cells, bacteria, etc.

11. Definitive Diagnosis of Exudative Effusion

• Light Criteria: Meets at least one of the following:
  • Pleural fluid protein/serum protein ratio > 0.5
  • Pleural fluid LDH/serum LDH ratio > 0.6
  • Pleural fluid LDH > 2/3 of the upper limit of normal serum LDH.
• Confirmation: Pleural fluid protein – serum protein ≤ 3.1 g/dL.

12. Rivalta Test

The Rivalta test detects protein in the fluid but doesn’t specify the type. It involves heating the fluid; if protein is present, it precipitates.

13. LDH (Lactate Dehydrogenase)

• Enzyme within cells: Catalyzes the conversion of pyruvate to lactate.
• Present in most tissues: Elevated levels indicate cell damage.
• Normal Range: 110-210 IU/L
• Elevated Serum LDH: Suggests tissue damage.
• 5 LDH Isoenzymes: Each specific to a particular tissue:
  • LDH 1: Heart + Red Blood Cells
  • LDH 2: Reticuloendothelial cells
  • LDH 3: Lung
  • LDH 4: Kidney, Pancreas, Placenta
  • LDH 5: Liver + Skeletal Muscle

Note: Patients with PE who are anemic should undergo coagulation testing before thoracentesis to prevent uncontrolled bleeding.

14. Why Never Perform Bilateral Thoracentesis?

Bilateral thoracentesis can cause bilateral pneumothorax, leading to rapid respiratory failure and a life-threatening situation.

15. Thoracentesis Precautions

• Withdraw less than 1 liter of fluid per session.
• Remove fluid slowly.
• Ensure a closed drainage system during thoracentesis.

Important Note: Rapid and excessive fluid drainage can trigger anaphylactic shock.

16. Complications of Thoracentesis

• Pneumothorax: Occurs if the needle punctures a pre-existing air pocket or causes lung perforation.
• Infection: Can occur at the puncture site or in the pleural space.
• Anaphylactic Reaction: Can occur if fluid drainage is too fast or excessive.
• Pneumothorax: Air leak into the pleural space, caused by needle puncture or lung tear.

17. Pleural Fluid Tests

• Cytology: Detects cancer cells.
• Biochemistry: Protein, LDH, amylase (in cases of acute pancreatitis), glucose, pH.
• Microbiology:
  • Gram stain: Identifies common bacteria.
  • Ziehl-Neelsen stain: Detects Mycobacterium tuberculosis.

18. What Causes Yellow Pleural Fluid?

• Transudative: Due to decreased plasma albumin (renal, liver diseases) or increased hydrostatic pressure (heart failure), leading to plasma leakage into the pleural space.
• Exudative:
  • Tuberculosis: Consider past TB history and “evening fever.”
  • Cancer: Primary lung cancer or metastasis.
  • Pneumonia: Inflammatory process.
  • Fungal Pneumonia: Inflammatory process.
  • Extra-pulmonary Inflammatory Conditions: Inflammatory processes outside the lung.

19. What Causes Bloody Pleural Fluid?

• Hemothorax: Pleural fluid hemoglobin/blood hemoglobin ratio > 0.5.
• Chest Trauma.
• Lung Cancer (Primary or Metastatic).
• Thoracic Aortic Dissection.
• Thoracentesis Complications.
• Rendu-Osler-Weber Syndrome.

20. Management of Transudative PE

Treat the underlying cause of hypoalbuminemia or increased hydrostatic pressure. Transudative PE often resolves spontaneously; drainage is only indicated if it causes dyspnea.

21. Management of Exudative PE

• Symptomatic Treatment: Drainage as needed.
• Treatment of Underlying Cause: Antibiotics, anti-TB drugs, etc.
• Prevention of Pleural Adhesions and Encapsulation: Prompt drainage and resolution of effusion.

22. Symptomatic Management of Exudative PE

• Respiratory Failure: Oxygen therapy, thoracentesis (maximum 1 liter per session).
• Large, Rapidly Recurring Effusion (Cancer): Pleurodesis (induction of pleural adhesions) using talc, povidone, etc.

Important Note: Pleurodesis is contraindicated if the lung is not expandable or if there is associated pericardial effusion.

23. Treatment of Underlying Causes of Exudative PE

• Infectious Pleuritis: Thoracentesis, drainage, daily pleural lavage with 0.9% NaCl, antibiotics (Cefa 3 + Respiratory Quinolone) for 4-6 weeks.
• Tuberculosis: Isoniazid, Rifampicin, etc.

24. Preventing Pleural Encapsulation and Adhesions

Early and complete drainage of the effusion is the best approach.

25. Management of Encapsulated Pleural Space

• Streptokinase Infusion: 300,000 units once daily into the pleural space.

Important Notes:

• Subsequent streptokinase infusions should be spaced at least 6 days apart.
• If using other fibrinolytics, avoid streptokinase to prevent allergic reactions.
• Pleural Scope: Can be used to break down adhesions.

26. Surgical Management of PE

• Pleural Decortication and Debris Removal: Considered after 1 month of unsuccessful medical management.
• Foreign Body Removal: For bullet fragments near the pleura.
• Ligation of Thoracic Duct: For chylothorax (caused by rupture or blockage of the thoracic duct).

27. Classifying Pneumothorax by Cause

• Primary Spontaneous Pneumothorax (PSP): Occurs in young adults (20-40 years), tall, thin individuals with a narrow chest, often triggered by strenuous activity. Cause: Bleb rupture.
• Secondary Spontaneous Pneumothorax (SSP): Occurs due to rupture of pre-existing lung lesions into the pleural space or strenuous activity. Lesions include lung abscesses, TB cavities, fungal infections, and chronic obstructive pulmonary disease (COPD).
• Traumatic Pneumothorax.
• Pneumothorax after Medical Procedures.

28. Menstrual Cycle-Associated Pneumothorax

• Occurs cyclically, primarily on the right side (90%).
• Cause: Endometriosis.
• Treatment: Hormone therapy, but high recurrence rate (50%).

29. Why Can Positive Pressure Mechanical Ventilation Cause Pneumothorax?

High-pressure ventilation can rupture lung alveoli. Early detection is crucial to prevent worsening respiratory failure.

30. Classifying Pneumothorax Based on Pleural Pressure

• Open Pneumothorax: Air freely moves in and out through a lung tear. When a syringe is attached: Piston moves in and out with each breath.
• Closed Pneumothorax: Lung tear seals itself, creating negative pleural pressure. Prognosis is good. When a syringe is attached: Piston is drawn inwards further.
• Tension Pneumothorax: Air enters the pleural space on inspiration but cannot escape, increasing intrapleural pressure above atmospheric pressure. When a syringe is attached: Piston is forcefully pushed outwards.
  • Signs: Distended chest on the affected side, mediastinal shift, respiratory failure, circulatory collapse.
  • Serious Prognosis, Rapid Death.

Note: When using a 20 ml syringe, withdraw 5 ml to observe piston movement.

31. Definitive Diagnosis of Pneumothorax

• Clinical: Gaillard’s Triad (diminished breath sounds, hyperresonant percussion, decreased vocal fremitus), sudden chest pain, dyspnea, tachypnea, dry cough.
• Investigations: Chest X-ray.

32. Differential Diagnosis of Pneumothorax

• Lung Bulla: Pre-existing air pocket without symptoms, thin walls, acute angle between the bulla and chest wall.
• Severe COPD: Lung hyperlucency, but peripheral lung markings remain visible.
• Pseudo-pneumothorax: Due to skin folds on the chest wall, breast tissue, etc.

33. Principles of Pneumothorax Management

Evacuate the air from the pleural space and prevent recurrence.

34. Methods for Evacuating Pleural Air

• Oxygen Therapy: For mild PSP.
• Simple Thoracentesis: For severe PSP, SSP after procedures.
• Chest Tube Drainage: For tension PNX, severe PSP due to trauma, SSP or post-procedural PNX that fails other methods, combined PNX/PE, SSP after mechanical ventilation.

35. Oxygen Therapy for Pneumothorax Management

• Indications: Mild PSP (air width < 2 cm, < 15% of chest volume).
• Procedure: Oxygen therapy at 2-3 liters/minute for 2-3 days. Repeat X-ray; if stable, remove tube.

36. Thoracentesis for Pneumothorax Management

• Indications:
  • Severe PSP (air width > 2 cm).
  • SSP after procedures: Thoracentesis, pleural biopsy, transthoracic lung biopsy.
• Procedure: Use a small needle, trocar, or catheter:
  • Small Needle: Evacuate air, remove needle.
  • Trocar: Evacuate air, clamp. Repeat X-ray after 12 hours; if no recurrence, remove trocar.
  • Catheter: Continuously evacuate using negative pressure (-20 cm H2O) until air is removed, clamp. Repeat X-ray after 24 hours; if no recurrence, remove catheter.

Note: If dyspnea increases or subcutaneous emphysema develops during clamping, reopen the drain immediately.

37. Chest Tube Drainage for Pneumothorax Management

• Indications:
  • Tension PNX.
  • Severe PSP due to trauma.
  • PSP or post-procedural PNX that fails other methods.
  • Combined PNX/PE.
  • SSP after mechanical ventilation.
• Procedure: Use a 16-28 French tube. Continuously evacuate using negative pressure (-20 cm H2O) until air is removed, clamp. Repeat X-ray after 24 hours; if no recurrence, remove tube.

Note: If dyspnea increases or subcutaneous emphysema develops during clamping, reopen the drain immediately.

38. Defining Drainage Failure

Air remains after 5 days of continuous drainage.

39. Indications and Methods for Pneumothorax Recurrence Prevention

• Indications:
  • PSP recurrence from the second episode onwards.
  • TPTP due to underlying conditions: COPD, old TB, interstitial lung disease.
  • Bullae or air pockets on X-ray/CT.
• Methods:
  • Pleurodesis using talc/povidone via chest tube.
  • Thoracoscopy/Open thoracotomy.

40. Pleurodesis Using Talc/Povidone for Pneumothorax Recurrence Prevention

• Infuse talc or povidone through a chest tube.
• Pause drainage, change patient position 15 minutes/session -> resume drainage after 2 hours.
• Important Note: Ensure complete fluid evacuation to allow for proper adhesion.
• Side effects: Significant pain, fever, PE.

41. Thoracoscopic Intervention for Pneumothorax Recurrence Prevention

• Pleurodesis: Talc instillation, pleural abrasion.
• Bulla management.

Important Points to Remember:

• Pleural effusion and pneumothorax are common conditions that can lead to respiratory failure and even death if not treated promptly.
• It is essential to diagnose and manage the underlying cause and prevent complications.
• Follow your doctor’s instructions carefully for thoracentesis, chest tube drainage, etc. to ensure patient safety.