Primary Pneumothoraces

Primary spontaneous pneumothoraces are thought to result from rupture of apical pleural blebs beneath the visceral pleura, which have been identified in up to 80% of affected patients on CT scan and 90% at thoracoscopy [2] compared to only 20% of control subjects. The blebs have no epithelial lining and result from rupture of the alveolar wall.

Classically, the patient is a tall, thin male aged 20-30 years old, with increased negative pressure shear forces at the apices being implicated in sub-pleural bleb formation. Similar mechanisms may account for the predisposition of patients with Marfan’s or Marfanoid habitus to this condition.

Smoking is associated with a 12% increased risk of developing pneumothorax in otherwise healthy men [1]. Female smokers have an overall 8 fold increase in risk. Genetic factors have been identified in a small number of familial clusters.