Pleural Diseases

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Pleural Effusion Essentials - Fluid Follies

Excess fluid in pleural space. CXR PA view showing right sided pleural effusion

  • Types:

    FeatureTransudateExudate
    MechanismSystemic (↑ hydrostatic, ↓ oncotic P)Local (↑ permeability, ↓ drainage)
    AppearanceClearCloudy/Bloody
    Protein (Pleural/Serum)< 0.5> 0.5
    LDH (Pleural/Serum)< 0.6> 0.6
    LDH (Pleural)< 2/3 ULN Serum> 2/3 ULN Serum
    CausesCCF, Cirrhosis, NephroticPneumonia, TB, Malignancy
  • 📌 Light's Criteria (Exudate if $\ge \mathbf{1}$):

    • Pleural fluid protein / Serum protein > 0.5 (i.e., $P_{prot}/S_{prot} > \mathbf{0.5}$)
    • Pleural fluid LDH / Serum LDH > 0.6 (i.e., $P_{LDH}/S_{LDH} > \mathbf{0.6}$)
    • Pleural fluid LDH > 2/3 ULN Serum LDH (i.e., $P_{LDH} > \frac{2}{3} \times \text{ULN Serum LDH}$)

⭐ India: Commonest transudate - CCF. Commonest exudate - TB/Parapneumonic.

  • Dx:
    • CXR: Costophrenic angle blunting (~200 mL), meniscus. Lateral decubitus (~50 mL).
    • USG: Sensitive (detects ~5-20 mL), guides thoracentesis.
    • Thoracentesis: Diagnostic (biochem, cytology, micro) & therapeutic.

Effusion Varieties - The Usual Suspects

  • Parapneumonic Effusion & Empyema: Associated with pneumonia.

    • Uncomplicated: Free-flowing; pH >7.2, Gluc >60 mg/dL, LDH <1000 IU/L. Rx: Antibiotics.
    • Complicated: Loculated OR pH <7.2, Gluc <60 mg/dL, LDH >1000 IU/L. Rx: ICD + antibiotics.
    • Empyema: Pus; +ve Gram/Culture. Rx: ICD, fibrinolytics (e.g. streptokinase), surgery if needed (decortication).
      • 📌 Stages: 1. Exudative → 2. Fibrinopurulent → 3. Organising.

    CXR & CT: Loculated pleural effusion

  • Tuberculous Pleural Effusion: Common extrapulmonary TB.

    • Exudative, straw-coloured; lymphocytes >80%.
    • ADA >40 IU/L highly suggestive. Pleural biopsy if doubt. Rx: ATT (6 months).

    ⭐ Adenosine Deaminase (ADA) >40 IU/L is a key diagnostic marker for tuberculous pleural effusion, especially in high TB prevalence areas.

  • Malignant Pleural Effusion: Primary (mesothelioma) or metastases (lung, breast, lymphoma).

    • Large, recurrent, often hemorrhagic. Dx: Cytology/pleural biopsy.
    • Rx: Therapeutic tap, pleurodesis (talc), IPC.

Air & Agony - Pneumothorax Puzzles

  • Types & Features:

    TypeCauseKey Feature
    Spontaneous
    - Primary (PSP)Ruptured subpleural bleb/bullaYoung, tall, thin males; smokers
    - Secondary (SSP)Underlying lung disease (e.g., COPD)More severe symptoms
    TraumaticPenetrating/blunt trauma, iatrogenicHistory of trauma/procedure
    TensionAir entry > air exit (one-way valve)Life-threatening; shock
  • Tension Pneumothorax: Medical emergency!

    • 📌 TRACHEA Mnemonic: Tracheal deviation (away), Respiratory distress (severe), Absent breath sounds (ipsilateral), Cyanosis, Hypotension, Engorged neck veins (JVD), Acute.
    • Immediate needle decompression: 2nd ICS mid-clavicular line OR 5th ICS mid-axillary line, then Intercostal Drain (ICD).

CXR: Left tension pneumothorax with mediastinal shift

⭐ Tension pneumothorax is a clinical diagnosis; immediate needle thoracostomy should precede radiographic confirmation if suspected due to its life-threatening nature.

Other Pleural Pathologies - Thoracic Troubles

  • Hemothorax: Blood in pleural space.
    • Causes: Trauma, iatrogenic, malignancy.
    • Dx: Pleural Hct > 0.5 × blood Hct.
    • Rx: Chest tube; thoracotomy if >1500mL initial or >200mL/hr for 2-4 hrs.
  • Chylothorax: Chyle (lymph) in pleural space.
    • Causes: Trauma (surgical), malignancy (lymphoma).
    • Dx: Milky fluid; ↑Triglycerides (>110 mg/dL), chylomicrons.
    • Rx: Treat cause, low-fat/MCT diet, octreotide.
  • Mesothelioma: Pleural malignancy.
    • 📌 Risk: Asbestos exposure (primary).
    • Imaging: Unilateral effusion, rind-like pleural thickening. Malignant pleural mesothelioma CXR and CT

    ⭐ Strongly linked to occupational asbestos exposure; long latency (20-40 yrs).

  • Light's criteria are crucial for differentiating exudative from transudative pleural effusions.
  • Tuberculous pleural effusion is typically exudative, lymphocyte-predominant, with high ADA (>40 U/L).
  • Malignant pleural effusion is often exudative, hemorrhagic, and cytology is key for diagnosis.
  • Empyema requires drainage (thoracostomy); characterized by pus or positive Gram stain/culture.
  • Pneumothorax types: spontaneous (primary/secondary), traumatic, tension (medical emergency, needle decompression).
  • Mesothelioma is strongly associated with asbestos exposure; presents with pleural thickening/effusion.
  • Chylothorax shows milky fluid with high triglycerides (>110 mg/dL) and cholesterol/triglyceride ratio <1.

Practice Questions: Pleural Diseases

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Flashcards: Pleural Diseases

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The presence of pleural fluid cholesterol usually > _____mg/dl is suggestive of pseudochylothorax

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The presence of pleural fluid cholesterol usually > _____mg/dl is suggestive of pseudochylothorax

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