When the injury is not noticed right away, the main symptoms are those that indicate bowel obstruction. Causes
Diaphragmatic rupture may be caused by blunt trauma, penetrating trauma, and by iatrogenic causes (as a result of medical intervention), for example during surgery to the abdomen or chest. It has also occurred spontaneously at the time of pregnancy or for no discernible reason. Injury to the diaphragm is reported to be present in 8% of cases of blunt chest trauma. In cases of blunt trauma, vehicle accidents and falls are the most common causes. Penetrating trauma has been reported to cause 12.3–20% of cases, but it has also been proposed as a more common cause than blunt trauma; discrepancies could be due to varying regional, social, and economic factors in the areas studied. Stab and gunshot wounds can cause diaphragmatic injuries. Clinicians are trained to suspect diaphragmatic rupture particularly if penetrating trauma has occurred to the lower chest or upper abdomen. With penetrating trauma, the contents of the abdomen may not herniate into the chest cavity right away, but they may do so later, causing the presentation to be delayed. Since the diaphragm moves up and down during breathing, penetrating trauma to various parts of the torso may injure the diaphragm; penetrating injuries as high as the third rib and as low as the twelfth have been found to injure the diaphragm. Iatrogenic cases have occurred as a complication of medical procedures involving the thorax or abdomen. It has occurred as a complication of thoracentesis and radiofrequency ablation.
Mechanism
Although the mechanism is unknown, it is proposed that a blow to the abdomen may raise the pressure within the abdomen so high that the diaphragm ruptures. Blunt trauma creates a large pressure gradient between the abdominal and thoracic cavities; this gradient, in addition to causing the rupture, can also cause abdominal contents to herniate into the thoracic cavity. Abdominal contents in the pleural space interfere with heart function and lung function. High intrathoracic pressure results in an increase in right atrial pressure, disrupting the filling of the heart and venous return of blood. As venous return determines cardiac output, this results in a reduction of cardiac output. If ventilation of the lung on the side of the tear is severely inhibited, hypoxemia (low blood oxygen) results. Usually, the rupture is on the same side as an impact. A blow to the side is three times more likely to cause diaphragmatic rupture than a blow to the front. Diagnosis
Physical examinations are not accurate, as there is usually no specific physical sign that can be used to diagnose this condition. Thoracoscopic and laparoscopic methods can be accurate. Chest X-ray is known to be unreliable in diagnosing diaphragmatic rupture; it has low sensitivity and specificity for the injury. Often another injury such as pulmonary contusion masks the injury on the X-ray film. Half the time, initial X-rays are normal; in most of those that are not, hemothorax or pneumothorax is present.