- Pneumothorax is an abnormal collection of air in the pleural space and classified as spontaneous (primary or secondary) or traumatic.
- Primary spontaneous pneumothorax usually occurs in the absence of underlying lung disease. Patients are classically described as tall men, aged 20 to 40 years, who are smokers.
- Secondary pneumothorax occurs due to lung pathology, including chronic obstructive pulmonary disease, cystic fibrosis, tuberculosis, asthma, interstitial lung disease, menstruation, and Pneumocystis jirovecii pneumonia.
- Traumatic pneumothoraces occur with blunt or penetrating trauma, including iatrogenic subclavian line placement or thoracentesis or following pleural or lung biopsy.
- Tension pneumothorax is a medical emergency and occurs in the setting of penetrating trauma, lung infection, and cardiopulmonary resuscitation or positive end expiratory pressure.
- Following spontaneous pneumothorax, 30% of patients experience a recurrence after either observation or tube thoracotomy treatment.
- Patient will typically complain of dyspnea and may have varying degrees of pleuritic chest pain. Severity of the symptoms generally correlates to severity of the pneumothorax.
- If the pneumothorax is small (<15% of a hemithorax), patient may have normal findings on examination.
- Patients with a larger pneumothorax may have tachypnea and tachycardia. On lung examination, hyperresonance to percussion, decreased tactile fremitus, and diminished breath sounds are present on the affected side.
- In a tension pneumothorax, findings may include a displaced point of maximal impulse, tracheal deviation, mediastinal shift, and hemodynamic instability.
- A visceral pleural line on the chest radiograph is diagnostic and may be noted only on the expiratory view.
- Chest CT may demonstrate the cause of a spontaneous secondary pneumothorax.
- In a tension pneumothorax, the diagnosis should be made based on the history and physical examination; however, radiographs would reveal mediastinal shift away from the affected side with a large amount of air in the pleural space.
- Left-sided primary pneumothorax may produce QRS axis and precordial T-wave changes that can be misinterpreted as an MI.
- Treatment of primary spontaneous pneumothorax depends on the size of the air collection in the pleural space.
- – A small pneumothorax will typically resolve on its own.
- – Supplemental oxygen therapy increases the rate of reabsorption.
- – Large pneumothorax: A smallbore catheter attached to a Heimlich valve may be used, with outpatient follow-up.
- – If the pneumothorax fails to resolve, a traditional chest tube attached to water seal drainage with suction may be used.
- Secondary spontaneous pneumothorax requires standard chest tube drainage using water seal drainage with suction and admission to the hospital. The underlying cause should then be addressed.
- Since most traumatic pneumothoraces occur concomitantly with hemothorax, treatment includes a large-bore chest tube with water seal and drainage with suction.
- In an unstable patient with a tension pneumothorax, immediate needle decompression should be performed with a 14- to 16-gauge needle inserted into the second intercostal space. Ultimately, the patient should have tube thoracostomy and water seal drainage with suction.
- Recurrent spontaneous pneumothoraces may require surgical resection of blebs or pleurodesis with talc.
>>QUESTIONS & ANSWERS<<
1. Which of the following is not an examination finding in pneumothorax?
a. Decreased tactile fremitus
c. Decreased resonance to percussion
d. Decreased breath sounds on the affected side
Explanation: When air leaks into the pleural space, the lung recoils from the chest wall and the increased air creates a hyperresonant sound to percussion.
2. Which of the following is not a cause of secondary spontaneous pneumothorax?
a. Chronic obstructive pulmonary disease
b. Pneumocystis jirovecii pneumonia
c. Penetrating lung trauma
d. Cystic fibrosis
Explanation: Penetrating lung trauma will cause a traumatic pneumothorax or, if large enough, a tension pneumothorax with hemodynamic instability, mediastinal shift away from the affected side, and tracheal deviation.