312.1 🎓 醫孞生版

312.1.0.1 📌 䞀頁重點

312.1.0.1.1 Pleural Effusion
312.1.0.1.1.1 Definition
  • Excess fluid in pleural space
  • Normal: ~ 10-15 mL serous fluid for lubrication
  • Pathologic: > 15-25 mL
312.1.0.1.1.2 Classification (Light’s Criteria)
  • Transudate vs Exudate distinction critical

Light’s Criteria (Exudate if ≥ 1): 1. Pleural protein / serum protein > 0.5 2. Pleural LDH / serum LDH > 0.6 3. Pleural LDH > 2/3 upper limit of normal serum LDH

If all 3 negative → transudate - High sensitivity for exudate (~ 98%) but moderate specificity - Can misclassify diuretic-treated CHF (~ 25%) as exudate

Alternative for Borderline: - Serum-Pleural Albumin Gradient > 1.2 suggests transudate - NT-proBNP in pleural fluid: ≥ 1500 pg/mL = HF cause

312.1.0.1.1.3 Transudate Causes (Imbalance of Starling Forces)
  • Heart failure (most common; bilateral, R > L)
  • Cirrhosis with hepatic hydrothorax (right > left)
  • Nephrotic syndrome
  • Atelectasis
  • Hypoalbuminemia
  • PE (some — typically exudate)
  • Peritoneal dialysis
  • CSF leak (post-spine surgery)
  • Hypothyroidism (rare)
  • Constrictive pericarditis
312.1.0.1.1.4 Exudate Causes (Increased Permeability)
  • Parapneumonic effusion / empyema
  • Malignancy (lung, breast, lymphoma, mesothelioma)
  • Pulmonary embolism (often exudate)
  • Tuberculosis
  • Autoimmune (RA, SLE)
  • Pancreatitis (left-sided usually)
  • Drug-induced (nitrofurantoin, methotrexate, amiodarone, propylthiouracil, dasatinib)
  • Chylothorax (lymphatic disruption)
  • Hemothorax (trauma, malignancy)
  • Esophageal rupture (Boerhaave; high amylase, low pH)
  • Subdiaphragmatic (pancreatitis, abscess)
  • Yellow nail syndrome
  • Asbestos (benign asbestos pleural effusion)
312.1.0.1.1.5 Clinical Features
  • Dyspnea (size-dependent)
  • Pleuritic chest pain (with inflammation)
  • Cough
  • Dullness to percussion
  • Decreased breath sounds
  • ↓ Fremitus
  • Pleural rub (if pleuritis)
  • Egophony at upper border (consolidation)
312.1.0.1.1.6 Imaging
  • CXR (PA + lateral):
    • Blunting of costophrenic angle (> 200 mL)
    • Meniscus sign (curvilinear upper border)
    • Lateral decubitus: better visualization
  • Ultrasound:
    • Bedside, quantifies, guides thoracentesis
    • Detects loculations
    • Anechoic = clear; complex = exudate/empyema
  • CT chest: characterizes, identifies underlying cause
312.1.0.1.1.7 Thoracentesis (Diagnostic + Therapeutic)

Indications for Diagnostic: - New or unexplained effusion - Suspected infection - Clinical suspicion of specific etiology

Routine Tests: - pH - Protein, LDH (Light’s criteria) - Glucose - Cell count + differential - Gram stain + culture - AFB - Cytology - Albumin

Additional Per Clinical: - ADA (TB) - Triglycerides + cholesterol (chylothorax) - Amylase (pancreatitis, esophageal rupture) - Cytology multiple samples for malignancy - BNP (HF) - Hematocrit (hemothorax: pleural/serum > 50%)

312.1.0.1.1.8 Specific Findings + Diagnosis

Glucose < 60 mg/dL: - Complicated parapneumonic / empyema - Rheumatoid (often very low) - Malignancy - TB - Lupus pleuritis

pH < 7.20: - Complicated parapneumonic / empyema - Rheumatoid - Malignancy

ADA > 40 IU/L: - TB pleurisy - Sometimes lymphoma, empyema

Lymphocytic Effusion (> 50%): - TB - Malignancy - Lymphoma - Chronic HF - Post-CABG

Neutrophilic Effusion: - Parapneumonic - Empyema - Pancreatitis

Eosinophilic Effusion (> 10%): - Drug-induced - Asbestos - Hemothorax - Pneumothorax - Lymphoma - Parasitic - Idiopathic (most common)

Amylase Elevated: - Pancreatitis - Esophageal rupture (very high) - Malignancy

312.1.0.1.2 Parapneumonic Effusion + Empyema
312.1.0.1.2.1 Definitions
  • Simple parapneumonic: clear, free-flowing, pH > 7.30, LDH < 1000, glucose > 60
  • Complicated parapneumonic: loculated, pH < 7.30, LDH > 1000, glucose < 60
  • Empyema: frank pus + positive Gram stain/culture
312.1.0.1.2.2 Management

Simple Parapneumonic: - Treat pneumonia (antibiotics) - Observe

Complicated Parapneumonic / Empyema: - Drainage (chest tube) - IV antibiotics - Intrapleural fibrinolytics + DNase for loculated (MIST-2 trial — tPA + DNase) - Surgical consultation if no improvement

Surgery (VATS or thoracotomy): - Failure of drainage - Persistent fever - Loculated empyema not resolving

312.1.0.1.2.3 Antibiotics
  • Empiric based on pneumonia source
  • Community-acquired: cover S. pneumoniae, anaerobes, S. aureus, GNR
  • Healthcare-associated: broader spectrum including MRSA, Pseudomonas
  • Tailor to cultures
  • Anaerobic coverage important
312.1.0.1.3 Malignant Pleural Effusion
312.1.0.1.3.1 Common Cancers
  • Lung (~ 30%)
  • Breast (~ 25%)
  • Lymphoma
  • Ovary
  • Stomach
  • Mesothelioma
312.1.0.1.3.2 Diagnosis
  • Cytology (multiple samples — sensitivity 50-70%)
  • Pleural biopsy (thoracoscopic — yield 90%+)
  • Immunohistochemistry
312.1.0.1.3.3 Management
  • Therapeutic thoracentesis (relief but reaccumulates)
  • Pleurodesis (chemical — talc, bleomycin via tube or VATS)
  • Tunneled pleural catheter (PleurX, TPC) — outpatient drainage
  • Surgical pleurectomy (rarely)
  • Treat primary malignancy
312.1.0.1.4 Mesothelioma (Pleural)
312.1.0.1.4.1 Background
  • Asbestos exposure (latency 20-40 years)
  • Increasing in industrialized
  • Pleural > peritoneal
312.1.0.1.4.2 Clinical
  • Chest pain (insidious)
  • Dyspnea
  • Recurrent pleural effusion
  • Weight loss
312.1.0.1.4.3 Diagnosis
  • CT chest
  • Pleural biopsy (gold standard — VATS or image-guided)
  • Immunohistochemistry: calretinin, WT-1, cytokeratin
  • Subtypes: epithelioid (60%, best prognosis), sarcomatoid (worst), biphasic
312.1.0.1.4.4 Treatment
  • CheckMate 743 (2021): nivolumab + ipilimumab > chemotherapy → first immunotherapy approval; especially in non-epithelioid
  • Cisplatin + pemetrexed: chemotherapy
  • Surgery (extended pleurectomy, pneumonectomy): selected
  • Radiation: adjuvant or palliative
  • Trimodality (surgery + chemo + radiation): controversial
312.1.0.1.4.5 Prognosis
  • Median 12-24 months untreated
  • With nivolumab + ipi: 18 months median OS (vs 14 months chemo)
312.1.0.1.5 Pneumothorax
312.1.0.1.5.1 Categories

Spontaneous: - Primary spontaneous pneumothorax (PSP): no underlying lung disease; tall thin young men (15-35 yo), smokers, family history - Secondary spontaneous pneumothorax (SSP): underlying lung disease — COPD (most common), CF, ILD, lung cancer, PCP

Traumatic: - Penetrating chest injury - Blunt trauma (rib fractures)

Iatrogenic: - Central line placement (subclavian) - Thoracentesis - Transbronchial biopsy - Mechanical ventilation - Cardiac procedures

Tension Pneumothorax (Medical Emergency): - One-way valve mechanism - Increasing pleural pressure → cardiovascular collapse - Treatment: immediate needle decompression (2nd ICS midclavicular OR 4-5th ICS midaxillary) then chest tube

312.1.0.1.5.2 Catamenial Pneumothorax
  • Recurrent during menstruation
  • Thoracic endometriosis
  • Treatment: hormonal suppression + surgery
312.1.0.1.5.3 Clinical Features
  • Sudden dyspnea + pleuritic chest pain
  • ↓ Breath sounds + hyperresonance
  • Tracheal deviation (tension)
  • Hypotension (tension)
312.1.0.1.5.4 Diagnosis
  • CXR (upright): visceral pleural line + absent lung markings beyond
  • CT (for small or complex)
  • Ultrasound (lack of pleural sliding, lung point)
312.1.0.1.5.5 Treatment

Primary Spontaneous (PSP): - Small (< 2-3 cm): observation + supplemental O2 - Moderate-large: aspiration + observation OR chest tube - Recurrent: VATS pleurodesis + bullectomy

Secondary Spontaneous (SSP): - More aggressive: chest tube usually - Higher recurrence - Pleurodesis often

Traumatic: - Chest tube (often) - Surgery if severe

Tension: - Needle decompression → chest tube

Iatrogenic: - Observation if small - Chest tube if symptomatic / increasing

312.1.0.1.5.6 Recurrence Prevention
  • VATS with pleurodesis or pleurectomy
  • After first SSP or second PSP
312.1.0.1.6 Chylothorax + Pseudochylothorax
312.1.0.1.6.1 Chylothorax
  • Lymphatic disruption → chyle (lymph + fat) into pleural space
  • Triglycerides > 110 mg/dL = diagnostic
  • Causes: trauma, surgery (thoracic, cardiac), malignancy (lymphoma), LAM
  • Treatment: low-fat diet, MCT, octreotide; surgery (thoracic duct ligation) if refractory
312.1.0.1.6.2 Pseudochylothorax
  • Chronic effusion → cholesterol crystals
  • Cholesterol > 200 mg/dL, TG < 110
  • Causes: chronic effusion (TB, RA)
  • Address underlying
312.1.0.1.7 Hemothorax
312.1.0.1.7.1 Definition
  • Blood in pleural space
  • Pleural/serum hematocrit > 50% = diagnostic
312.1.0.1.7.2 Causes
  • Trauma
  • Malignancy
  • PE (rare)
  • Iatrogenic
  • Spontaneous (rare)
312.1.0.1.7.3 Management
  • Chest tube (large bore)
  • Surgery if persistent bleeding
  • VATS for retained hemothorax
312.1.0.1.8 Pleural Fluid Asbestos (Benign Asbestos Pleural Effusion, BAPE)
  • Asbestos exposure history
  • Often blood-tinged exudate
  • Diagnosis of exclusion
  • Self-limited but recurrent
  • Long-term: pleural fibrosis
312.1.0.1.9 Yellow Nail Syndrome
  • Nail dystrophy + lymphedema + pleural effusion
  • Lymphatic dysfunction
  • Treatment: symptomatic

312.1.0.2 🩺 床邊速查

  • Light’s criteria for exudate: any of (P/S protein > 0.5, P/S LDH > 0.6, pleural LDH > 2/3 upper limit)
  • Transudate: HF, cirrhosis, nephrotic, atelectasis
  • Exudate: parapneumonic/empyema, malignancy, PE, TB, autoimmune, drug
  • Complicated parapneumonic: pH < 7.30, LDH > 1000, glucose < 60 → chest tube
  • Empyema + loculation: MIST-2 intrapleural tPA + DNase
  • PSP: tall thin young men; small → observe + O2; large → aspiration/chest tube
  • SSP: underlying disease → chest tube usually
  • Tension pneumothorax: needle decompression → chest tube (EMERGENCY)
  • Chylothorax: TG > 110; pseudochylothorax: cholesterol > 200
  • Hemothorax: pleural/serum Hct > 50%
  • Mesothelioma: nivolumab + ipilimumab (CheckMate 743)