Pulmonary Embolism (PE)

The thrombus or clot in a deep vein may become dislodged and be carried in the circulation to eventually block an artery. This is known as an embolus. It usually occurs within 7 days of the formation of a DVT (new clot formation).

Emboli arising from a deep vein usually travel through the heart to lodge in an artery of the lungs; this is known as pulmonary embolism. Pulmonary embolism can be life-threatening and indeed causes death if the embolus is large. However, it may cause an infarct in (or death of) the lung tissue if it is smaller. This can cause breathlessness, depending on how much of the lung tissue is affected.

N.B. Calf compression and walking do not “set off” an embolus.

DVT’s are regarded seriously because of their capacity to lead to a large (or “massive”) pulmonary embolus, and subsequent possible death.

Disabling Effects

Small pulmonary emboli would normally cause small infarcts in the lung tissue, with consequent pain, breathlessness and haemoptysis (coughing blood). The degree with which the person is affected depends on the size and number of the emboli, the treatment which is given, and the likely speed of recovery. A massive PE will be fatal. Multiple focal pulmonary emboli will reduce lung capacity, and cause respiratory restriction.

Amended April 2008