Pulmonary embolism

A pulmonary embolism is when material obstructs the lumen of the pulmonary artery or one of its distal branches. Usually this material is a blood clot (also know as a thrombus) that dislodges from a distal vein and travels to the heart. When the pulmonary artery is obstructed, this can lead to rapid heart failure (imagine the right ventricle of the heart trying to contract and push blood against an obstruction) or a sudden arrhythmia (a change in the electrical signal passing through the heart tissue). Smaller emboli can also be problematic as this prevents blood flow to the lung tissue, which can cause the tissue to die.

Symptoms of a pulmonary embolism can include difficulty breathing, chest pain, rapid heart rate, and nausea, but some people experience no symptoms.

There are multiple risk factors for blood clots, including tobacco product use, increasing age, female gender, inherited clotting disorders, cancer, serious infections, immobility or prolonged periods of decreased movement (such as long plane rides), and obesity.

Other causes of emboli include air embolism, amniotic fluid embolism (a rare but serious complication of childbirth), fat embolism (a rare complication of a bone fracture), septic (bacteria laden material from an infection site in the body), and other material (such as cancer or tissue dislodged during surgery).