Pleural disease Flashcards
What is a pleural effusion?
A collection of fluid in the pleural cavity
What are the two classes of pleural effusion?
Exudative meaning there is a high protein count (>35g/L) or transudative meaning there is a relatively lower protein count (<25g/L).
25–35g/L - If pleural fluid protein/serum protein >0.5, effusion is an exudate (85% specific and sensitive)
What are the exudative causes of a pleural effusion?
Exudative causes are related to inflammation. The inflammation results in protein leaking out of the tissues in to the pleural space.
- Lung cancer
- Pneumonia
- Rheumatoid arthritis
- Tuberculosis
Transudative causes of pleural effusion
Transudative causes relate to fluid moving across into the pleural space.
- ↑ venous pressure (cardiac failure, constrictive pericarditis, fluid overload)
- Hypoalbuminaemia (cirrhosis, nephrotic syndrome,malabsorption)
- Hypothroidism
- Meig’s syndrome (right sided pleural effusion with ovarian malignancy)
Symptoms of pleural effusion
- Asymptomatic or
- Dyspnoea
- Pleuritic chest pain
Signs of pleural effusion
- decreased expansion
- stony dullness to percussion
- reduced breath sounds (may be bronchial breathing where lung compressed above the effusion)
- decreased vocal ressonance
- with large effusions there may be tracheal deviation away from the effusion
What are the investigations for a pleural effusion and what would they show?
Chest X-ray
- Blunting of the costophrenic angle
- Fluid in the lung fissures
- Larger effusions will have a meniscus. This is a curving upwards where it meets the chest wall and mediastinum.
- Tracheal and mediastinal deviation if it is a massive effusion
Diagnostic aspiration, analyse it for
- protein count
- cell count
- pH
- glucose
- LDH
- microbiology testing.
Treatment of pleural effusion
- Conservative management may be appropriate as small effusions will resolve with treatment of the underlying cause
- Pleural aspiration can temporarily relieve the pressure but the effusion may recur and repeated aspiration may be required
- Chest drain can be used to drain the effusion and prevent it recurring
- Talc pleurodesis can be helpful in recurrent effusions
How would you perfrom a diagnostic aspiration of pleural fluid?
- Percuss the upper boarder of the pleural effusion and choose a site 1 to 2 intercostal spaces below it (don’t go to low or you’ll be in the abdomen)
- Infiltrate down to the pleura with 5-10ml of 1% lidocaine
- Attach a 21G needle to a syringe and insert it just above the upper boarder of an appropriate rib (to avoid the neurovascular bundle)
- Draw 10-30ml of pleural fluid and send it to the lab
What is an empyema?
Pus in the pleural space
What would pleural aspiration of an empyema show?
- pus
- acidic pH (pH < 7.2)
- low glucose
- high LDH
How is an empyema treated?
Antibiotics and chest drain to remove pus.
Intrapleural alteplase and dornase alpha may be helpful.
What is a pneumothorax?
Pneumothorax occurs when air gets into the pleural space
Causes of pneumothorax
- Primary spontaneous pneumothorax
- Secondary due to lung disease
- COPD
- asthma
- bronchiectasis
- ILD
- Iatrogenic, such as due to:
- lung biopsy
- mechanical ventilation
- central line
- Trauma
Describe the typical exam patient with pneumothorax
Tall, thin young man presenting with sudden breathlessness and pleuritic chest pain
What investigation is used to diagnose a pneumothorax?
Erect chest x-ray
- A chest x-ray will show an area between the lung tissue and the chest wall where there are no lung markings.
- There will be a line demarcating the edge of the lung where the lung markings end and the pneumothorax begins.
How is the size of a pneumothroax measured on an x-ray?
The pneumothorax is measured horizontally from the lung edge to the inside of the chest wall at the level of the hilum.
Why may at CT thorax be of use in a pneumothorax?
- to detect a pneumothorax too small to see on an x-ray
- to accurately measure the size of the pneumothorax
Management of pneumothorax based on the 2010 guidelines from the British Thoracic Society:
- If no SOB and there is a < 2cm rim of air on the chest xray then no treatment required as it will spontaneously resolve. Follow up in 2-4 weeks is recommended.
- If SOB and/or there is a > 2cm rim of air on the chest xray then it will require aspiration and reassessment.
- If aspiration fails twice it will require a chest drain.
- Unstable patients or bilateral or secondary pneumothoraces generally require a chest drain.
Pathophysiology of tension pneumothorax
Tension pneumothorax is caused by trauma to chest wall that creates a one-way valve that lets air in but not out of the pleural space. The one-way valve means that during inspiration air is drawn into the pleural space and during expiration, the air is trapped in the pleural space. This is dangerous as it creates pressure inside the thorax that will push the mediastinum across, kink the big vessels in the mediastinum and cause cardiorespiratory arrest.
Signs of tension pneumothorax
- Tracheal deviation away from side of pneumothorax
- Reduced air entry to affected side
- Increased resonance to percussion on affected side
- Tachycardia
- Hypotension
Management of tension pneumothorax
- Insert a large bore cannula into the second intercostal space, midclavicular line
- Inset chest drain
Chest drains are inserted into the “triangle of safety”. This triangle is formed by:
What do you do after inserting a chest drain?
- The 5th intercostal space (or the inferior nipple line)
- The mid axillary line (or the lateral edge of the latissimus dorsi)
- The anterior axillary line (or the lateral edge of the pectoris major)
After chest drain inserted order an x-ray to check positioning
