A<unk> , also known as lung<unk> , is a bruise of the lung, caused by chest trauma. As a result of damage to capillaries, blood and other fluids accumulate in the lung tissue. The excess fluid interferes with gas exchange, potentially leading to inadequate oxygen levels (hypoxia). Unlike pulmonary laceration, another type of lung injury,<unk>  does not involve a cut or tear of the lung tissue. A<unk>  is usually caused directly by blunt trauma but can also result from explosion injuries or a shock wave associated with penetrating trauma. With the use of explosives during World Wars I and II,<unk>  resulting from blasts gained recognition. In the 1960s its occurrence in civilians began to receive wider recognition, in which cases it is usually caused by traffic accidents. The use of seat belts and airbags reduces the risk to vehicle occupants. Diagnosis is made by studying the cause of the injury, physical examination and chest radiography. Typical signs and symptoms include direct effects of the physical trauma, such as chest pain and coughing up blood, as well as signs that the body is not receiving enough oxygen, such as cyanosis. The<unk>  frequently heals on its own with supportive care. Often nothing more than supplemental oxygen and close monitoring is needed; however, intensive care may be required. For example, if breathing is severely compromised, mechanical ventilation may be necessary. Fluid replacement may be required to ensure adequate blood volume, but fluids are given carefully since fluid overload can worsen pulmonary edema, which may be lethal. The severity ranges from mild to severe: small<unk> s may have little or no impact on health, yet<unk>  is the most common type of potentially lethal chest trauma. It occurs in 30–75% of severe chest injuries. The risk of death following a<unk>  is between 14–40%.<unk>  is usually accompanied by other injuries. Although associated injuries are often the cause of death,<unk>  is thought to cause death directly in a quarter to half of cases. Children are at especially high risk for the injury because the relative flexibility of their bones prevents the chest wall from absorbing force from an impact, causing it to be transmitted instead to the lung.<unk>  is associated with complications including pneumonia and acute respiratory distress syndrome, and it can cause long-term respiratory disability.
Pulmonary contusion
Hemothorax
Pulmonary hematoma
Diaphragmatic rupture
Urinothorax
Hemopneumothorax
Hydropneumothorax
Flail chest