Pulmonary embolism is a situation where a pulmonary vessel in either or both lungs gets blocked. The blockage is produced by one or more blood clots, which have moved through the veins from different body parts. Usually, pulmonary embolisms are created by a clot being shifted from smaller vessels in the arm or heart. The blood clot progresses through the venous system until it reaches a spot from where it can no longer move freely. Blood flow, as a result of this, is decreased to the troubled area of the lung. It may generally break up and go back into the bloodstream without a problem; however, if the clot is big, it may block a vein and stop the flow of blood to an organ. If that organ is the heart, brain, or lung, the consequences might be fatal.

Symptoms of a pulmonary embolism mainly include perspiration, chest pain, change in pallor, and shortness of breath.

Causes of pulmonary embolism
There are several known causes of pulmonary embolism. The primary ones have been listed below:
Pregnancy – Pulmonary embolism is the original cause of death in gestation. During pregnancy, the body faces changes in its system of central blood clotting. Therefore, the blood is prone to clot and is more viscous. Women who have to undergo Caesarean deliveries have an added threat due to major abdominal surgery.
Birth control pills – The presence of estrogen in birth control pills can raise clotting agents in blood, particularly if one is overweight or has a habit of smoking. Moreover, the risk of clots from birth control pills is small compared to the risks associated with pregnancy.
Post-operative complications – Owing to reduced movement, post-operative patients are at a higher threat of forming clots. This is due to the circulatory disorder caused by the surgery and consequent immobility, which decreases the flow of blood throughout the body.
Extended periods of bed rest – Old people are at a larger risk as this group is a primary victim of immobility and spend most of the time without any physical activity.

Diagnostic tests for pulmonary embolism
Since the signs of a pulmonary embolism can resemble other medical conditions, specific diagnostic tests are required to diagnose the condition.
Electrocardiogram (ECG) – ECG alterations can be present in a patient exhibiting pulmonary embolism. This should not be overlooked in cases where there are no notable ECG changes.
C.T. scan – This requires a contrast dye being inserted into a venous cannula. Pictures are then taken to perceive the flow of the dye through the venous system and into the pulmonary vessels. If there are any poorly perfused or blocked areas, a C.T. scan will intimate this.
Pulmonary angiography – This test demands the insertion of a catheter into a large vein located in the groin. Pulmonary angiography is done; however, this procedure is invasive, difficult to interpret, and can give false-negative results as well.
Erect chest X-ray – In maximum cases of a speculated pulmonary embolism, a physician will ask for a chest X-ray to be done. This test will not reveal any abnormality, which will help the diagnosis of a pulmonary embolism. However, it can highlight other possible conditions, which may be causing the symptoms to appear.

Treatment of pulmonary embolism
Pulmonary embolism needs proper treatment for it to go away. In cases of a speculated pulmonary embolism, the doctor will prescribe anticoagulant injections as a preventative course until an accurate diagnosis has been established. These injections are given subcutaneously and include a low molecular weight known as heparin.

In some cases, intravenous heparin is initiated during the crucial period, following diagnosis. The chief purpose of heparin is to dilute the blood. In the treatment of pulmonary embolism, thinning the blood in time ends in the reduction of blood clots. It is usually given for a restricted period, typically in the critical phase of diagnosis and for some weeks. After that, the patient will be anticoagulated with Warfarin therapy, which can be monitored closely in the primary care situation.

During an anticoagulant therapy, it is essential that the patient undergoes periodic blood tests to regulate and control clotting levels in the blood. In critical cases, where a patient becomes severely ill as a consequence of an enormous pulmonary embolism, it is usually imperative to treat him or her quickly with a thrombolytic agent. Patients suffering from a massive pulmonary embolism are likely to display hemodynamically unstable traits with associated critical respiratory distress. Therefore, intensive treatment is important.