Clinical exam · Respiratory system
Pleural effusion syndrome !
- Syndrome
Fluid between the lung and the chest wall: the base sounds dull and voice and breath sounds are barely heard.
Updated 2026-11-01
See it in 3D: Pleura · Diaphragm
What it is
A pleural effusion is fluid collecting in the pleural space. The fluid lies between lung and wall, damps vibration and sound, and gathers first at the bases by gravity. It is a transudate (pressure imbalance, as in heart failure) or an exudate (inflammation or tumour of the pleura, as in pneumonia, tuberculosis or cancer).
Key findings
- Light's criteria (fluid protein and LDH compared with serum) separate exudate from transudate.
- Persistent fever with an effusion in a patient with pneumonia calls for ruling out empyema.
Pathophysiology
- The pleura normally holds a very thin film of fluid that is made and absorbed in balance.
- Transudate: hydrostatic pressure rises or oncotic pressure falls (heart failure, cirrhosis, nephrotic syndrome).
- Exudate: pleural permeability rises or lymphatic drainage is blocked (infection, tumour, autoimmune disease).
- Upright, fluid collects first in the posterior costodiaphragmatic recess.
| Inspection | Palpation (fremitus) | Percussion | Auscultation |
|---|---|---|---|
| Small to moderate: expansion ↓ on that side; trachea midline | Reduced fremitus at the base | Basal dullness with a border rising toward the axilla | Reduced breath sounds; egophony at the upper border |
| Massive: hemithorax full and still; trachea to the opposite side | Absent fremitus | Dullness over the whole hemithorax | Breath and voice sounds absent |
Common causes
- Heart failure (transudate, often bilateral).
- Pneumonia with parapneumonic effusion or empyema.
- Tuberculous pleurisy.
- Lung cancer, pleural metastases and mesothelioma.
- Pulmonary embolism, cirrhosis, nephrotic syndrome; haemothorax after trauma.
Tests that confirm it
- Chest radiograph: blunted costophrenic angle and a meniscus.
- Pleural ultrasound: detects small volumes and guides the tap.
- Thoracentesis with fluid analysis (Light's criteria, chemistry and cell count, culture, cytology; adenosine deaminase if tuberculosis is suspected).
Test yourself
Think of the answer, then tap the question to see it.
Which voice finding may be heard at the upper border of an effusion?
Egophony, from the compressed lung just above the fluid.
Which way does a massive effusion push the trachea?
To the opposite side, from the mass effect of the fluid.
What is the most common cause of a pleural transudate?
Heart failure.
Which imaging test finds small effusions and guides the tap?
Pleural ultrasound.
See it in 3D
The structures of Durgical's 3D anatomy where it is found.
Related
- The pleuropulmonary syndromes: the comparison table to know
- Chest percussion: resonance, dullness and hyperresonance
- Voice sounds: bronchophony, egophony and whispered pectoriloquy
- Pneumothorax syndrome
- Heart failure syndrome: left- and right-sided signs
Related conditions
- Pleural effusion
- Parapneumonic effusion and empyema
- Heart failure
- Pulmonary tuberculosis
- Haemothorax
- Lung cancer
Educational content on the clinical exam; it is learned and practised under supervision. It does not replace assessment by a health professional and is not for self-diagnosis.
Sources: Pleural effusion: MedlinePlus Medical Encyclopedia (MedlinePlus, U.S. National Library of Medicine, 2024); Breath sounds: MedlinePlus Medical Encyclopedia (MedlinePlus, U.S. National Library of Medicine, 2024).
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Representative model, for educational purposes only.