Pneumothorax is entry of air into the pleural space either from the lung or
through the chest wall. Air may enter the cavity because of spontaneous (sudden,
unexpected) rupture of lung tissue or because of trauma to the chest wall and/or lung
(creates an air leak).
Classification and Etiology and Pathology
- Classified as iatrogenic (following a specific event) or spontaneous
- Iatrogenic pneumothorax follows procedures such as lung biopsy,
thoracentesis, trauma, etc.
- Spontaneous pneumothorax can occur in all lung disease,
e.g., lung cancer, emphysema, diffuse
interstitial fibrosis, etc. Spontaneous idiopathic pneumothorax occurs when
small blebs of peripheral tissue rupture without warning or apparent cause. Young people
are more commonly affected. A cough may lead to sudden pain and dyspnea.
- Mechanical ventilation with PEEP predisposes to development of
barotrauma and pneumothorax.
- Spontaneous pneumothorax also is encountered in patients with apparent
normal lungs. Consider in this group congenital blebs, Marfan's, Ehlers-Danlos
Syndrome and endometriosis.
- Patients present with sudden onset of SOB, chest pain and cough.
- Cyanosis, shift of mediastinum, larger
ipsilateral hemithorax, decreased chest expansion, hyper-resonance and decreased
breath sounds are characteristic physical findings.
- Tension pneumothorax is present when the air leak is
progressive. Venous return decreases resulting in falling blood pressure, tachycardia,
worsening SOB and hypoxemia.
- Asymptomatic pneumothorax is due to one time entry of air into
the pleural space and can resolve spontaneously in a few days. Chest tube is not required
in this instance.
- Symptomatic pneumothorax however small, requires either chest
tube or Heimlich valve placement immediately.