Pleural Effusion

Classification

•    Transudates (low protein, <30 g/L)

o    Causes:

    Heart failure (most common)

    Hypoalbuminaemia (e.g., nephrotic syndrome, liver cirrhosis)

    Constrictive pericarditis

•    Exudates (high protein, >30 g/L)

o    Causes:

    Infection (parapneumonic, TB)

    Malignancy (lung, breast, lymphoma)

    Pulmonary embolism

    Connective tissue disease (RA, SLE)

Light’s Criteria (exudate if any are true)

•    Pleural fluid protein / serum protein >0.5

•    Pleural fluid LDH / serum LDH >0.6

•    Pleural fluid LDH > two-thirds upper limit of serum normal

Investigations

•    CXR: blunting of costophrenic angle; lateral decubitus film shows layering

•    Ultrasound: guides aspiration

•    Diagnostic tap:

o    pH <7.2 → empyema

o    Low glucose → RA, empyema, TB, malignancy

o    High amylase → pancreatitis, oesophageal rupture

Management

•    Drainage if large, symptomatic, or infected (empyema)

•    Treat underlying cause

Pneumothorax

Types

•    Primary spontaneous pneumothorax (PSP)

o    Typically young, tall, thin men

o    Subpleural blebs rupture

•    Secondary spontaneous pneumothorax (SSP)

o    Occurs with underlying lung disease (COPD, ILD, CF)

•    Traumatic/iatrogenic

o    E.g., central line insertion, positive-pressure ventilation

Tension Pneumothorax

•    Severe breathlessness, hypotension, tracheal deviation away, hyperresonant

•    Emergency: immediate needle decompression

o    Large bore cannula in 2nd ICS midclavicular line, then insert chest drain (5th ICS midaxillary line)

Management (British Thoracic Society)

•    PSP

o    <2 cm and no breathlessness → observe

o    2 cm or symptomatic → aspirate first, then drain if unsuccessful

•    SSP

o    2 cm or symptomatic → chest drain

o    <1 cm and asymptomatic → consider oxygen and observe

Mesothelioma

Features

•    Malignant pleural tumour; strongly linked to asbestos exposure

•    Long latency (~30–40 years)

Clinical

•    Dyspnoea, pleuritic chest pain

•    Recurrent unilateral pleural effusion

•    Weight loss

Imaging

•    CXR: unilateral effusion, pleural thickening, calcified pleural plaques (old asbestos exposure)

•    CT: helps assess local invasion

Diagnosis

•    Pleural fluid cytology (low yield)

•    Thoracoscopic biopsy (definitive)

Prognosis

•    Very poor; median survival ~12 months

Management

•    Mainly palliative: pleurodesis, analgesia

•    Chemotherapy (pemetrexed + cisplatin)

Extra Revision Pearls

•    Transudate clues → systemic causes (e.g., HF, cirrhosis)

•    Low pleural glucose → RA, empyema, TB, cancer

•    High pleural amylase → think pancreatitis or oesophageal rupture

•    Tension pneumothorax = clinical diagnosis → do not wait for CXR!

•    Trachea deviates away from tension pneumothorax; towards collapse/effusion

•    Asbestos exposure + recurrent effusion → mesothelioma until proven otherwise

•    Bilateral pleural plaques → classic marker of asbestos exposure