- Clinical science
A pneumothorax develops when air as the result of disease or injury enters the pleural space, resulting in the loss of negative pressure between the two pleural membranes. This loss of negative pressure leads to the partial or complete collapse of the lung. Pneumothorax is classified as spontaneous (e.g., by rupture of a subpleural bleb or diseased lung), traumatic, or iatrogenic. Each type can lead to a tension pneumothorax, which is a life-threatening variant of pneumothorax. Patients with pneumothorax present with sudden-onset dyspnea, ipsilateral chest pain, diminished breath sounds, and hyperresonant percussion on the affected side. A tension pneumothorax additionally presents with distended neck veins, tracheal deviation, and hemodynamic instability. Both should be suspected on clinical evaluation. While a tension pneumothorax requires immediate chest decompression, a chest x-ray may be considered to confirm the diagnosis in a stable patient. Small pneumothoraces may resorb spontaneously, but treatment of larger defects usually requires placement of a chest tube to re-establish the negative pressure within the pleural space.
- A pneumothorax is a collection of air within the pleural space in between the lung (visceral pleura) and the chest wall (parietal pleura) that can lead to partial or complete pulmonary collapse.
- Spontaneous pneumothorax: spontaneously occurring pneumothorax
- Tension pneumothorax: life-threatening variant of pneumothorax characterized by progressively increasing pressures within the chest and cardiorespiratory compromise
- Primary (idiopathic or simple pneumothorax)
Secondary (pneumothorax as a complication of underlying lung disease)
- Catamenial pneumothorax (extremely rare; thoracic endometriosis)
- Pulmonary aluminosis
- Pulmonary Langerhans cell histiocytosis (histiocytosis X) → rupture of cysts
- → bronchiectasis with obstructive emphysema and bleb or cyst rupture
- → alveolitis, rupture of a cavity
- (smoking) → rupture of bullae in emphysema
- Traumatic pneumothorax: blunt (e.g., motor vehicle accident with impact of thorax onto the steering wheel or rib fracture) or penetrating (e.g., gunshot) injury
- Iatrogenic pneumothorax: Mechanical ventilation (Mechanical ventilation with high PEEP may result in barotrauma); , thoracocentesis; , central venous catheter placement, or bronchoscopy
A tension pneumothorax may occur with any of the above-mentioned etiologies!References:
- Increased intrapleural pressure → alveolar collapse → decreased V/Q ratio and increased right-to-left shunting
- Spontaneous pneumothorax: rupture of blebs and bullae → air moves into pleural space with increasing positive pressure; → ipsilateral lung is compressed and collapses →
- Closed pneumothorax: air enters through a hole in the lung (e.g., following blunt trauma)
- Open pneumothorax: air enters through a lesion in the chest wall (e.g., following penetrating trauma)
- Tension pneumothorax: disrupted visceral pleura, parietal pleura, or tracheobronchial tree → air enters the pleural space on inspiration but cannot exit; → progressive accumulation of air in the pleural space and increasing positive pressure within the chest ; → collapse of ipsilateral lung and compression of contralateral lung, trachea, heart, and superior vena cava → impaired respiratory function, reduced venous return to the heart and reduced cardiac output → hypoxia and hemodynamic instability
Clinical features vary from asymptomatic to cardiopulmonary compromise
- Sudden, severe, and/or stabbing, ipsilateral pleuritic chest pain and dyspnea
- Reduced, or absent breath sounds, hyperresonant percussion, decreased fremitus on the ipsilateral side
- Subcutaneous emphysema
- Additionally in tension pneumothorax:
Suspected pneumothorax is confirmed by chest x-ray.
- Immediate x-ray or an extended focused assessment with sonography for trauma (eFAST) in adults with severe respiratory compromise and children
- CT may provide detailed information about the underlying cause (e.g., bullae in spontaneous pneumothorax).
- Tension pneumothorax is primarily a clinical diagnosis and prolonged diagnostic studies should be avoided to initiate immediate treatment.
- ABG) to detect respiratory acidosis (
Chest x-ray (confirmatory test)
- Ideally in two projections (PA and lateral), in supine and upright position
Chest x-rays are often performed in expiration because it is believed that this allows better detection of small pneumothoraces.
- Ipsilateral pleural line with reduced/absent lung markings
- Sudden change in radiolucency
- Deep sulcus sign: dark and deep costophrenic angle on the affected side
- If pulmonary disease is present: airway or parenchymal lesions
- Additional features in tension pneumothorax:
- Ipsilateral diaphragmatic flattening/inversion and widened intercostal spaces
- Tracheal deviation towards the contralateral side
CT: In stable adults without severe respiratory compromise and responsive to resuscitation. Other indications:
- Presurgical workup
- Suspected underlying lung disease, to determine the likelihood of recurrent disease
- Uncertain diagnosis despite chest x-ray
ECG: for all patients with anterior chest trauma
- Reduced QRS amplitude in leads V2–V6 in left-sided pneumothorax
- Increased QRS amplitude in leads V5–V6 in right-sided pneumothorax
- ST elevation or depression
A negative eFAST does not exclude a pneumothorax!
In cases of tension pneumothorax, immediate decompression is a priority and should not be delayed by imaging!References:
- For details and further differential diagnoses, see
The differential diagnoses listed here are not exhaustive.
If small (≤ 2 to 3 cm between the lung and chest wall on a chest x-ray) and asymptomatic
- Usually resolve spontaneously within a few days (∼ 10 days)
- Supplemental oxygen (4-6 L/min) via nasal cannula or mask with reservoir
- Serial follow-up with repeat CXR
- If small and symptomatic (but hemodynamically stable) or large (> 3 cm between the lung and chest wall on chest x-ray) primary pneumothorax, iatrogenic, traumatic, or secondary pneumothorax
- Immediate supplemental oxygen (4-6 L/min) via nasal cannula or mask with reservoir
- Upright positioning
- Symptomatic treatment
- Tube thoracostomy
- If small (≤ 2 to 3 cm between the lung and chest wall on a chest x-ray) and asymptomatic
- Simple partially occlusive dressings taped at 3 out of 4 sides of the lesion
- Followed by thoracostomy
- Observe for development of tension pneumothorax
- Emergency chest decompression via chest tube placement if immediately available
- Otherwise perform emergency needle thoracostomy, followed by chest tube placement
Chest tube placement
- Local anesthesia
- Incision of the skin and blunt dissection down to the upper margin of the rib within the respective ICS → cranial subcutaneous tunneling → opening of the parietal pleura approx. 1–2 ICS above the cutaneous incision
- Insertion and placement of the chest tube depends on the injury
- Air → apically, close to the pleural cupula
- Fluid (e.g., blood, effusion) → caudally
- Fixation of pleural drain to the chest wall
- Application of suction with a negative pressure of -20 to -25 cmH2O for 3–5 days or until the air leak has stopped.
- A water-seal may be used (a valve prevents entrance of air into the pleural space).
- Needle thoracostomy
- Stitching of the leak or resection of the lung regions that have bullae, if necessary (apical lung resection)
Tension pneumothorax is a clinical diagnosis and medical emergency! Immediate emergency chest decompression is indicated! Do not intubate and ventilate without decompressing first!
- Complete pulmonary collapse → respiratory failure
- Tension pneumothorax → cardiac failure
- Mediastinal flutter in case of open pneumothorax → hemodynamic shock
- Hemothorax in cases of trauma
- Post-surgical/-procedural complications
- Persistent fistula with continuous air leak
- Injury to intercostal nerves and vessels
We list the most important complications. The selection is not exhaustive.