Pleural Diseases

Pleural Effusions - Fluid Follies

Fluid in pleural space. Differentiated by Light's Criteria.

• Light's Criteria (Exudate if ≥1):
  • Pleural/Serum Protein > 0.5
  • Pleural/Serum LDH > 0.6
  • Pleural LDH > $\frac{2}{3}$ ULN serum LDH (>200 IU/L)

• Transudate (Systemic: ↑Hydrostatic/↓Oncotic pressure):
  • CHF (commonest), Cirrhosis, Nephrotic Syndrome, PE.
• Exudate (Local: ↑Pleural permeability/↓Lymphatic drainage):
  • Infection (Pneumonia, TB - commonest exudative in India), Malignancy, PE, Autoimmune.

• Features: Dyspnea, cough, pleuritic pain. Stony dullness, ↓breath sounds.
• Dx: CXR (PA >200ml, Lat Decubitus >50ml), Thoracentesis.
• Rx: Treat cause. Therapeutic tap for large effusions.

⭐ Meigs' syndrome: Benign ovarian tumor + ascites + pleural effusion (transudate). Resolves post-tumor removal.

Pneumothorax - Air Escapades

• Definition: Air in pleural space → lung collapse.
• Types:
  • Spontaneous:
    • Primary (PSP): No lung disease; apical bleb rupture (tall, thin young males).
    • Secondary (SSP): Underlying lung disease (COPD, TB, asthma).
  • Traumatic: Penetrating/blunt chest trauma.
  • Iatrogenic: Post-medical procedure (central line, biopsy).
• Tension Pneumothorax: ⚠️ Emergency!
  • One-way valve → ↑ intrapleural pressure.
  • Mediastinal shift (away), ↓ venous return, cardiovascular collapse. Tracheal deviation.
• Clinical: Acute dyspnea, pleuritic pain, ↓ breath sounds, hyperresonant percussion.
• Diagnosis:
  • CXR: Visceral pleural line, absent lung markings. Deep sulcus sign (supine).
  • USG: No lung sliding ("barcode sign"); lung point sign (specific).
  • CT: Most sensitive; detects small pneumothorax, bullae.
• Management:

• Pleurodesis: For recurrent/persistent cases (talc, doxycycline).

⭐ Deep Sulcus Sign: On supine CXR, a deep, lucent costophrenic angle suggests pneumothorax.

Pleuritis & Empyema - Inflammatory Invasions

• Pleuritis: Pleural inflammation. Causes: Infection (pneumonia, TB), malignancy, autoimmune (SLE). Sx: Sharp pleuritic chest pain, fever.
• Empyema: Pus in pleural space. Common organisms: S. aureus, S. pneumoniae, anaerobes.
  • Stages:
    • Exudative: Sterile exudate, ↑capillary permeability.
    • Fibrinopurulent: Bacterial invasion, frank pus, fibrin deposition.
    • Organizing: Fibroblast proliferation, thick pleural peel, potential trapped lung.
  • Diagnosis: Thoracentesis. Pleural fluid: pH < 7.20, glucose < 60 mg/dL, LDH > 1000 IU/L, ↑WBCs, positive Gram stain/culture.

  ⭐ Frank pus on aspiration, positive Gram stain/culture from pleural fluid, OR pleural fluid pH < 7.20 confirms empyema.

• Treatment: Systemic antibiotics, complete pleural fluid drainage (e.g., chest tube, VATS/decortication). Complication: Fibrothorax.

Pleural Tumors - Neoplastic Nightmares

• Primary tumor: Malignant Mesothelioma (MM); Secondary: Metastases (more common).
• Malignant Mesothelioma (MM)
  • Strongly linked to asbestos exposure (long latency: 20-40 years). 📌 "A"sbestos for "M"esothelioma.
  • Gross: Thick, white, gelatinous sheets encasing lung ("pleural rind").
  • Histology:
    • Epithelioid (most common, ~60%; better prognosis).
    • Sarcomatoid (~20%; worst prognosis).
    • Biphasic (~20%; intermediate prognosis).
  • IHC Markers: Calretinin+, WT-1+, CK5/6+, D2-40+ (positive); CEA- (negative) (vs. Adenocarcinoma).
  • Symptoms: Insidious onset chest pain, dyspnea, weight loss, recurrent effusions.

  ⭐ Psammoma bodies can be seen in epithelioid mesothelioma.

• Metastatic Pleural Tumors
  • Most common pleural malignancy.
  • Primaries: Lung > Breast > Ovary, Lymphoma.
  • Often presents as malignant pleural effusion, leading to dyspnea.

High‑Yield Points - ⚡ Biggest Takeaways

• Light's criteria differentiate transudative (e.g., CHF, cirrhosis) from exudative (e.g., infection, malignancy) effusions.
• Tuberculous pleurisy typically presents as a lymphocytic exudate with elevated ADA (>40 U/L).
• Malignant effusions are often hemorrhagic; cytology is key for diagnosis.
• Empyema, pus in the pleural space, necessitates thoracentesis and often chest tube drainage.
• Tension pneumothorax is a medical emergency requiring immediate needle decompression.
• Mesothelioma is strongly linked to asbestos exposure and has a poor prognosis.