"Variable from being completely asymptomatic to severe respiratory distress. Symptoms include dyspnoea, cyanosis and chest pain. Physical examination may reveal decreased breath sounds and hyperresonance to percussion on the affected side with contralateral tracheal deviation. When under tension, cardiac function may be compromised."
"Air dissects from alveolar spaces into interstitial spaces of lung. The eventual migration of air to the visceral pleura culminates in rupture into the pleural cavity. It may also be accompanied by pneumomediastinum, pneumopericardium, pneumoperitoneum or subcutaneous emphysema."
"There are a few signs that are useful in the diagnosis of a small pneumothorax:"
"hyperlucent hemithorax sign is seen as unilateral or bilateral areas of increased lucency confirmed on cross-table lateral view; the air will be seen to accumulate anteriorly"
"medial stripe sign is seen as an area of increased lucency at the interface of the medial lung and the mediastinum which can be confirmed on lateral decubitus view; the air will be seen to rise and accumulate along the lateral chest wall"
"Small, asymptomatic pneumothoraces are left alone and kept under close observation. Larger or symptomatic ones require drainage. Acute tension may be relieved with needle aspiration; chest tube or pigtail drainage may be placed afterwards for complete evacuation."