Pneumothorax Flashcards
What is a pneumothorax?
Occurs when air gains access to, and accumulates in, the pleural space.
What are the risk factors for pneumothorax?
- Cigarette smoking
- Family history of pneumothorax
- Tall and slender body build
- Age <40
- Recent invasive medical procedure
- Chest traume
- COPD
- Acute severe asthma
Briefly describe the pathophysiology of a pneumothorax
Normally, the alveolar pressure is greater than the intrapleural pressure, while the intrapleural pressure is less than atmospheric pressure. Therefore, if a communication develops between an alveolus and the pleural space, or between the atmosphere and the pleural space, gases will follow the pressure gradient and flow into the pleural space. This flow will continue until the pressure gradient no longer exists or the abnormal communication has been sealed. Because the thoracic cavity is normally below its resting volume, and the lung is above its resting volume, the thoracic cavity enlarges and the lung becomes smaller when a pneumothorax develops.
What are the different types of pneumothorax?
- Spontaneous (primary, secondary and recurrent)
- Traumatic
- Tension
Describe the 3 different types of spontaneous pneumothorax (primary, secondary and recurrent)
- Primary pneumothorax: occurs without clinically apparent pulmonary disease
- Secondary pneumothorax: occurs as a complication of an underlying pulmonary disease, including COPD, asthma, and thoracic endometriosis (catamenial pneumothorax).
- Recurrent pneumothorax: a second episode of spontaneous pneumothorax, either ipsilateral
or contralateral.
What is a traumatic pneumothorax?
Results from either penetrating or blunt injury to the chest. These may be the result of accidental or non-accidental injury.
What is a tension pneumothorax?
Occurs when the intrapleural pressure exceeds atmospheric pressure throughout expiration and often during inspiration. It is a medical emergency that requires prompt decompression.
What are the signs of a pneumothorax?
- Ipsilateral reduced breath sounds
- Ipsilater hyper-inflation of the hemithorax with hyper-resonance on percussion
- Hypoxia
What are the symptoms of a pneumothorax?
- Chest pain
- Dyspnoea
What investigations should be ordered for a pneumothorax?
- Chest X-ray
- Blood tests
- Chest ultrasound
- ABG
- CT chest
Why investigate using chest x-ray?
Use erect posterior-anterior (PA) chest x-ray as the first-line investigation in stable patients.
A visible rim between the lung margin and chest wall, or surgical emphysema and absence of lung markings between the lung margin and chest wall.
How does pneumothorax present on CXR?
A chest xray 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 ends and the pneumothorax begins.
How does a tension pneumothorax present on CXR?
A chest xray 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 ends and the pneumothorax begins.
It will also show tracheal deviation away from side of pneumothorax.
Why investigate using blood tests?
Order a full blood count and clotting screen. Correct clotting abnormalities (INR ≥1.5 or platelets ≤50 x 10⁹/L) before inserting a chest drain in patients who are not critically unwell.
Baseline levels.
Why investigate using chest ultrasound?
Increasingly used to detect pneumothorax, especially for patients who are immobilised following trauma, when an erect PA chest x-ray cannot be obtained.
Absence of pleural sliding; the ‘A’ line sign; presence of ‘lung point’ and ‘barcode’ sign.
Why investigate using ABG?
Consider an ABG if oxygen saturations are ≤92% on room air. It may aid in ruling out other differential diagnoses but is not usually necessary.
Respiratory alkalosis is the most common finding.
Why investigate using CT chest?
Order a CT chest if the diagnosis is uncertain on chest x-ray and the patient remains symptomatic, or in stable patients with significant chest trauma.
CT thorax can detect a small pneumothorax that is too small to see on a chest xray or be used to accurately assess the size of the pneumothorax.
Briefly describe how to measure the size of a pneumothorax
Measuring the size of the pneumothorax on a chest xray can be done according to the BTS guidelines from 2010. This involves measuring horizontally from the lung edge to the inside of the chest wall at the level of the hilum.
Briefly describe BTS guidelines for the treatment for pneumothorax
Note: if no SOB and there is a < 2cm rim of air on the chest xray
This is 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.
Briefly describe BTS guidelines for the treatment for pneumothorax
Note: if SOB and/or there is a > 2cm rim of air on the chest xray
This is based on the 2010 guidelines from the British Thoracic Society.
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.
Briefly describe BTS guidelines for the treatment for pneumothorax
Note: unstable patients or bilateral or secondary pneumothoraces
This is based on the 2010 guidelines from the British Thoracic Society.
If aspiration fails twice it will require a chest drain.
Unstable patients or bilateral or secondary pneumothoraces generally require a chest drain.
Where is a chest drain inserted?
Chest drains are inserted into the “triangle of safety”. This triangle is formed by:
- 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)
The needle is inserted just above the rib to avoid the neurovascular bundle that runs just below the rib. Once the chest drain is inserted obtain a chest xray to check the positioning.
What are the complications of pneumothorax?
- Pulmonary oedema (following lung re-expansion)
- Respiratory failure (hypoxaemic)
- Respiratory or cardiac arrest
- Empyema
What differentials should be considered for pneumothrax?
- Acute asthma exacerbation
- Acute COPD exacerbation
- Pulmonary embolism
- Myocardial infarction
