The key dangers of internal bleeding include hypovolaemic shock (leading to exsanguination), causing a tamponade on the heart or a haemothorax on the lung. The aortic aneurysm is a special case where the aorta, the body's main blood vessel, becomes ruptured through an inherent weakness. This is one of the most serious medical emergencies a patient can face, as the only treatment is rapid surgery, although exertion, raised blood pressure or sudden movements could cause a sudden catastrophic failure.[18]