Pleural Diseases

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Pleural Effusions - Water Woes

  • Types & Causes:
    • Transudate: ↑ hydrostatic or ↓ oncotic pressure (CHF, cirrhosis, nephrotic).
    • Exudate: ↑ pleural permeability (pneumonia, malignancy, TB, PE).
    • Light's Criteria (Exudate if ≥1): (📌 5-6-2/3)
      • Pleural Fluid Protein/Serum Protein > 0.5
      • Pleural Fluid LDH/Serum LDH > 0.6
      • Pleural Fluid LDH > 2/3 Upper Limit of Normal Serum LDH.
  • Imaging:
    • CXR: Costophrenic angle (CPA) blunting (>200ml), meniscus sign, subpulmonic effusion, vanishing tumor (fissural). Lateral decubitus: confirms free fluid. CXR Pleural Effusion Meniscus Sign
    • USG: Anechoic (transudate) vs. complex/septated (exudate); ideal for thoracentesis guidance.
    • CT: Loculations, pleural enhancement, underlying lung pathology.

⭐ A subpulmonic effusion can mimic an elevated hemidiaphragm; a lateral decubitus X-ray showing layering of fluid is key for confirmation.

Pneumothorax - Air Scare

  • Types:
    • Spontaneous:
      • Primary: No underlying lung disease (e.g., ruptured apical blebs in tall, thin males)
      • Secondary: With underlying lung disease (e.g., COPD, TB, cystic fibrosis)
    • Traumatic: Due to penetrating or blunt chest trauma
    • Iatrogenic: Resulting from medical procedures (e.g., central line insertion, lung biopsy)
  • CXR Signs:
    • Visible visceral pleural line (sharp white line of the collapsed lung edge)
    • Absent peripheral lung markings beyond the pleural line
    • Expiratory films: May enhance visibility of small pneumothoraces
    • Deep sulcus sign: On supine CXR, indicates air collection anteroinferiorly, deepening the costophrenic angle

      ⭐ The 'deep sulcus sign' on a supine chest X-ray is a critical indicator of pneumothorax, especially in trauma or ICU patients.

  • Tension Pneumothorax (EMERGENCY!):
    • Mediastinal shift (contralateral, away from PTX)
    • Diaphragmatic depression (ipsilateral)
    • ↑ Hyperlucent hemithorax, widened intercostal spaces
  • CT Chest:
    • Gold standard for detecting small or loculated pneumothoraces
    • Identifies underlying cause (e.g., bullae, blebs, cysts)

Tension pneumothorax with mediastinal shift

Pleural Infections & Thickening - Gunk & Grime

  • Parapneumonic Effusion (PPE): Exudate with pneumonia.
    • Uncomplicated: Free-flowing; antibiotics.
    • Complicated: Loculated; needs drainage.
  • Empyema: Pus in pleural space. Criteria:
    • pH < 7.20
    • Glucose < 60 mg/dL
    • LDH > 1000 IU/L
    • Positive Gram stain/culture.
  • Imaging (Empyema):
    • CXR: Lenticular opacity.
    • CECT: Split pleura sign, thickened/enhancing pleura, gas. CECT Chest: Split Pleura Sign of Empyema
    • USG: Loculations, septations; guides drainage.

⭐ 'Split pleura sign' (CECT): thickened, enhancing visceral & parietal pleura separated by complex fluid; highly suggestive of empyema.

  • Pleural Thickening Causes: Post-infection (TB), asbestos, post-hemothorax, malignancy.
  • Pleural Calcification:
    • Asbestos: Parietal/diaphragmatic plaques; spares costophrenic angles/apices.
    • TB: Extensive, visceral; 'empyema necessitans' (pus tracks through chest wall).

Pleural Masses - Lumps & Bumps

FeatureMalignant MesotheliomaMetastases
EtiologyStrong asbestos link (long latency)Most common; Primaries: Lung, breast, lymphoma, ovary
ImagingNodular/lobulated circumferential thickening, lung encasement, ipsilateral volume ↓, fissure involvement, large effusionMultiple nodules/plaques, effusion, often bilateral
LateralityUsually unilateralOften bilateral

⭐ Malignant mesothelioma typically causes circumferential, nodular pleural thickening that encases the lung, often associated with a history of asbestos exposure and may lead to ipsilateral lung volume loss.

  • Solitary Fibrous Tumor of Pleura (SFTP)
    • Mostly benign; can be large, pedunculated/sessile.
    • Associations:
      • Hypoglycemia (Doege-Potter syndrome).
      • Hypertrophic osteoarthropathy (Pierre Marie-Bamberger syndrome).
  • Lipoma
    • Fat density on CT.

High‑Yield Points - ⚡ Biggest Takeaways

  • Pleural effusion: Meniscus sign on CXR; Light's criteria for exudate vs. transudate.
  • Pneumothorax: Visceral pleural line visible; tension type is an emergency with mediastinal shift.
  • Empyema: Loculated pus in pleural space, requires prompt drainage.
  • Hemothorax: Blood in pleural cavity, often post-traumatic; CT density >50 HU.
  • Mesothelioma: Aggressive tumor linked to asbestos; causes large unilateral effusion, nodular pleural thickening.
  • Chylothorax: Milky pleural fluid due to lymph; high triglyceride levels (>110 mg/dL).

Practice Questions: Pleural Diseases

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True statement regarding pathology of pneumocystis jiroveci pneumonia:

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Flashcards: Pleural Diseases

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Pulmonary _____ is seen on x-ray in VSD due to large volume of shunted blood passing through the lungs

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Pulmonary _____ is seen on x-ray in VSD due to large volume of shunted blood passing through the lungs

plethora

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