Symptomatic pneumothorax (summary)

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  This is abasic article for for medical students and other non-radiologists

Pneumothoraces(singular: pneumothorax) are collections of gas within the pleural space. If the pneumothorax is under pressure, it is called a tension pneumothorax.

Clinical presentation

Patients with pneumothoraces tend to present with pleuritic chest pain and dyspnoea. If there is underlying lung disease, dyspnoea tends to predominate whereas if the patient does not have underlying lung disease, pain tends to be the dominant symptom.

Pathophysiology

Pneumothoraces may be spontaneous or occur after trauma (which may be iatrogenic). Spontaneous pneumothoraces may be secondary to underlying lung disease, e.g. asthma, COPD.

Pneumothoraces can therefore be split into 3 groups:

• primary spontaneous: no no underlying lung disease
• secondary spontaneous: underlying underlying lung disease, e.g. asthma, COPD
• secondary: to trauma, e e.g. car accident, stabbing, gun-shot, medical intervention (post lung biopsy)

Primary spontaneous pneumothoraces are predominantly caused by rupture of pleural blebs or bullae and predominantly occur in tall, thin, adolescent males ¹.

Clinical presentation

Patients with pneumothoraces tend to present with pleuritic chest pain and dyspnoea. If there is underlying lung disease, dyspnoea tends to predominate whereas if the patient does not have underlying lung disease, pain tends to be the dominant symptom.

Radiographic features

To make the diagnosis of a pneumothorax, look for:

• peripheral lucency
• a lung edge
• absence of lung markings peripheral to visible lung edge

On an erect chest radiograph, a pneumothorax will usually be apical. If it is small, it can be difficult to see. Look carefully in the region above the line of the clavicle.

If there is a pneumothorax, check for the position of the mediastinum. If the pneumothorax is under pressure, there may be compression of the heart and great vessels with displacement of the mediastinum away from the pneumothorax. This is called a tension pneumothorax and must be treated with urgency.

Treatment and prognosis

Treatment depends on the presence or absence of symptoms, the underlying cause, and its size (a small pneumothorax is less than 2 cm in depth)²:

• small pneumothorax with minimal symptoms
  • primary spontaneous pneumothorax: discharge with early outpatient follow up and advise to return if symptomatic
  • secondary pneumothorax: observe with high-flow oxygen therapy and consider intervention
• symptomatic pneumothorax

A small pneumothorax with marked breathlessness may indicate developing tension.

Prognosis is variable and dependant on the underlying cause.

DifferentialRadiographic differential diagnosis

• tension pneumothorax
• skin fold
• mastectomy
• rotated film