pneumothorax and subcutaneous emphysema

The CT above is of a 40 year-old male patient who fell from a ladder. Palpation of the chest produced the typical “crackling sensation” of subcutaneous emphysema. The scan shows a large right pneumothorax with right lung collapse, a right rib fracture, and extensive subcutaneous emphysema. There were multiple other rib fractures and a fractured right clavicle (not shown).

Subcutaneous emphysema
The presence of gas within the tissue beneath the skin. Subcutaneous emphysema is a rare finding and usually related to the introduction of air into tissues (such as through a pneumomediastinum). It can also occur from the production of gas within a tissue by infection such as in gas gangrene.

A collection of air or gas in the chest causing the lung to collapse. Pneumothorax may present with sudden chest pain, dyspnoea, chest tightness, fatigue, tachycardia, or cyanosis. Stethoscope examination of the chest reveals decreased breath sounds on the affected side. Diagnostic tests include chest X-ray and arterial blood gases (ABG often normal).

The most common cause of hemothorax is chest injury. Other causes include cancer, a defect of the blood clotting mechanism, thoracic surgery, or pulmonary (lung) infarction. In a chest injury, a rib may lacerate lung tissue or an artery.

Rib fractures
The most common complication of chest trauma usually involving the fifth through the ninth ribs. Fractures of the first three ribs are rare and are associated with laceration of the subclavian artery. Fractures of the lower ribs are associated with injury to the spleen and liver. The patient will experience severe pain, tenderness, and muscle spasm over the site of the fracture. There may be bruising around the fracture site. A crackling grating sound in the thorax may be detected. Occurs in over 60% of patients admitted with chest trauma. Most rib fractures are benign and are treated conservatively

Reference: McMillan, J. Types of Chest Trauma, personal website.

Credit: Fernando Leite