Pulmonary embolism (PE) is a complication that results from a block in the main artery supplying the lungs, or one of its branches.
Most of the time, the block is due to a blood clot (thrombus) that has detached itself from the deep veins in the legs and traveled all the way to the lungs. Hence, this process is known as venous thromboembolism.
Diagnosis of pulmonary embolism is initiated by recording the medical history followed by physical examination. Symptoms such as chest pain or breathlessness should arouse suspicion of PE.
Specific tests that help to diagnose PE are:
(a) Blood tests to assess blood count, ESR, clotting status, liver function and electrolytes
(b) Imaging studies such as selective pulmonary angiography and CT pulmonary angiography. The latter is non-invasive.
(c ) Ventilation -perfusion scintigraphy
(d) Chest x-ray, leg Doppler, ECG and ECHO are also used as diagnostic procedures to detect PE.
The first thing to do in treating pulmonary embolism is to shift the patient to a hospital and start oxygen and an IV line on the way, if possible.
a) Anticoagulant therapy- Anticoagulants or blood thinners such as heparin, low molecular heparin or fondaparinux are initially administered while warfarin, is used for long – term treatment. In cancer patients or pregnant women, low molecular weight heparin as warfarin is contraindicated.
Blood flow is usually restored quite rapidly within the first two days.
b) Thrombolysis – The use of enzymes to destroy a clot can be done in the case of massive or unstable PE.
c) Surgery-Surgery is not a popular mode of treatment for PE but in the case of chronic pulmonary embolism which leads to pulmonary hypertension, pulmonary thrombo-endarterectomy is employed.
Mortality from untreated PE is approximately 26%.
Prognosis of PE is dependant on the extent of lung damage in the patient and also on the existence of other ailments. In chronic lung embolism, the embolus formed must be resolved for the patient to survive.
Once anticoagulation therapy is stopped, there still exists a 0.5% risk of a fatal pulmonary embolism each year.