Pulmonary Embolism

In pulmonary embolism, the embolus typically comes from the deep veins of the leg where a thrombosis has formed (especially when sitting for long periods, e.g. on long-haul flights). The embolus then detaches from the thrombus material in the leg vein, is transported to the heart via the venous system and finally lands in one of the four pulmonary arteries or their branches. In rare cases, the embolic material may also come from the right heart or the superior vena cava.

The pulmonary arteries carry oxygen-poor blood from the heart to the lungs, where it is enriched with oxygen and then transported back to the heart via the pulmonary veins. If a pulmonary artery is “blocked” by the embolus, less blood can be supplied with oxygen, which is noticeable by shortness of breath and rapid breathing. In addition, patients complain of chest pain and have an increased heart rate.

In severe cases cyanosis in the head/neck area (blue coloration of the skin) occurs, in very severe cases unconsciousness and possibly cardiovascular arrest. If the pulmonary embolism is very small, i.e. only a small branch of the pulmonary arteries is blocked, no symptoms need to occur. The diagnosis of a pulmonary embolism is made by a CT scan with contrast medium.

In addition, various laboratory values are determined to rule out, for example, a heart attack (which would present with very similar symptoms). Treatment of a minor pulmonary embolism in the acute phase is carried out with heparin, a blood-thinning medication, as well as with oxygen and painkillers. Larger pulmonary embolisms are treated with fibrinolysis (a drug that is intended to dissolve the embolus) or, in absolute emergencies, with surgery.

A cholesterol embolism – not to be confused with fat embolism – is caused by the occlusion of a vessel containing cholesterol crystals. This happens in people whose vessels are riddled with cholesterol-containing plaques (arteriosclerosis), and in whom such a plaque dissolves and becomes stuck again downstream in the vessel. In most cases, a cholesterol plaque dissolves due to medical measures that manipulate the vessel wall (e.g. heart catheter, central venous line).

The rare cement embolism (also called “Palacos embolism” after the name of the most common cement) is caused by the occlusion of one or more vessels with bone cement during orthopedic surgery. During these operations, bones are usually opened to anchor prostheses and closed again with cement. During this procedure, small pieces of cement are probably washed into the bloodstream, which constricts in the pulmonary vessels and traps the cement particles as if in a filter.

During the operation, this is usually already noticed by an acceleration of the patient’s heartbeat and breathing. It is still unclear to what extent hypersensitivity reactions and simultaneous fat embolisms play a role in this.

The most common source of embolism is deep vein thrombosis of the leg.
Afterwards, the fat embolism is relevant, which is washed into the bloodstream during operations on the bone,
Followed by cholesterol and cement embolisms.