Primary Spontaneous Pneumothorax and Different Types of Surgical Management

pneumothorax is defined as air or gas accumulated in the pleural cavity. Spontaneous pneumothorax can be classified as either primary or secondary. Primary spontaneous pneumothorax , which is defined as a pneumothorax without underlying lung disease, predominantly occurs in young, thin males. It is usually caused by ruptured pleural blebs or bullae. Secondary spontaneous pneumothorax usually occurs in older people with underlying pulmonary disease, such as emphysema or asthma, acute or chronic infections, lung cancer, and congenital diseases including cystic fibrosis, catamenial pneumothorax , or lymphangio-leiomyomatosis .

The age-adjusted incidence of Primary spontaneous pneumothorax is from 7.4 to 18 per 100 000 population per year in males, and from 1.2 to 6 per 100 000 population per year in females. It usually occurs in tall, thin males of 10 to 30 years old. Less often does it occur in people at the age of more than 40 years. Primary spontaneous pneumothorax might be associated with some congenital disorders such as Marfan's syndrome, or some environmental factors such as smoking. Primary spontaneous pneumothorax usually occurs at rest. Approximately 10% of patients with Primary spontaneous pneumothorax have a positive family history. Smoking is also regarded as a precipitating factor for Primary spontaneous pneumothorax. The relative risk of pneumothorax ranged from 7 to 100 times higher in light to heavy smokers Most authors believe that Primary spontaneous pneumothorax results from spontaneous rupture of a sub-pleural bleb or bulla. However, only a portion of patients with Primary spontaneous pneumothorax could be found with blebs or bullae in imaging or at the time of surgery. Other mechanisms may be considered, such as increase in pleural porosity secondary to inflammation. The development of bullae, blebs, or pleural porosity might be related to many factors, such as distal airway inflammation, distal bronchial tree anomaly, disorders of connective tissue formation, local ischemia, and malnutrition.

Primary spontaneous pneumothorax usually occurs at rest, and presents with acute onset of local pleuritic chest pain accompanied by dyspnoea. This pain may be mild or severe, sharp and steady ache in character, and usually resolves within 24 h even though pneumothorax still exists. On physical examination, decreased air entry on auscultation, decreased chest wall movement on inspection, hyper-resonance (tympanic) on percussion are most often detected in patients with large pneumothorax (free air occupies more than 15% to 20% area of hemi thorax). Reflex tachycardia can be found in most patients in response to discomfort or circulating or respiratory compromise. Tension pneumothorax should be suspected if severe tachycardia, cold sweating, hypotension, or cyanosis has developed. Blood gas analysis in patients with large pneumothoraces may reveal increased alveolar-arterial difference in oxygen partial pressure (PA-aO2) due to increased intrapulmonary shunt from the collapsed lung.

Most Primary spontaneous pneumothorax cases are confirmed by upright posteroanterior chest radiograph, which can be used to assess the pneumothorax size with good accuracy. A pleural line with or without an air-fluid level can be seen in the chest radiograph, but sometimes it is difficult to detect these signs, especially in patients with small pneumothoraces, emphysema, or poor exposure of the film. Expiratory chest radiographs have no diagnostic value for patients with Primary spontaneous pneumothorax.

Computed tomography (CT) of the chest can be used to detect patients with small penman-thorax (less than 15% area of hemi thorax). In addition, CT can provide more detailed information to assist in the subsequent management. Findings which can be noted include the number, size, and location of bullae/blebs (ipsi- or contra-laterally), as well the possibilities of pleural adhesion, pleural fluid accumulation, and possible underlying pulmonary diseases. For more than 90% of patients with Primary spontaneous pneumothorax, pathological lung changes can be detected by CT. The most common type is few (n<5) and small (<2 cm in diameter) blebs, followed by mixed blebs and bullae (>2 cm in diameter).