Blood Clot in Lungs (Pulmonary Embolism)

The human body comprises of a pair of organs in the chest called the lungs, which are responsible for the exchange of oxygen and carbon dioxide between the air we breathe and the blood in our body. The function of the lungs is to provide oxygen from the atmosphere to the bloodstream and to release carbon dioxide from the bloodstream into the atmosphere. The air we breathe enters the lungs and the exchange of gases takes place through the arterial and venous system. A clot is formed in the lungs is called pulmonary embolism. The clot is actually formed in the veins of the lower regions of the body, such as the leg, pelvis, arms or even heart. The clot travels from its origin into the vessels of the lungs and continues to enter the smaller and narrower vessels until it comes to such a narrow vessel which does not permit it to go any further. This results in the wedging of the clot in the blood vessel. The clot wedge prevents blood from traveling past it to the other side of the lung, thereby inhibiting that portion of the lung from receiving oxygen. This is called pulmonary embolism. The clot that travels from one part of the body to another part is termed as embolus. The body is seen to break up the small clots quickly and tries to keep the damage minimum. However, large clots or emboli can cause the particular lung area to die and can even result in death. About 1% of the population suffers from pulmonary embolism.

Causes of Pulmonary Embolism

The most common cause of pulmonary embolus formation is a blood clot in the veins of the lower legs and is termed as Deep Vein Thrombosis (DVT). In rare cases, fat droplets, clumps of parasites, tumor cells and even air bubbles are seen to cause the clot in lungs. Precipitating factors that can trigger this type of clot formation are:

• A recent surgery, trauma or injury (especially to the legs)
• Cancer, estrogen therapy or heart disease
• Spinal cord injury
• Broken bones
• Stroke
• Certain protein and enzyme deficiencies
• Fracture of the hip or femur
• Prolonged bed rest or travel
• Prolonged inactivity
• Burns
• Child birth

Prolonged immobilization can result in clot formation in the arms and legs. Further, in some cases prolonged travel in cars, airplane and so on can also lead to clot formation. This is because the blood is allowed to stay in one position for a long period of time. Those people who have clotting disorders are at greater risk to develop pulmonary embolism.

Symptoms of Pulmonary Embolism

The symptoms of pulmonary embolism are vague and not all these symptoms are necessarily seen. Some of the commonly observed signs are:

• Apprehension and anxiety
• Chest pain (sharp, stabbing pain)
• Dry cough (sometimes bloody sputum is also observed)
• Low blood pressure
• Rapid heart rate (tachycardia)
• Sweating
• Nasal flaring
• Clammy skin
• Pelvic pain
• Shortness of breath at rest or with exertion
• Dizziness or passing out
• Swelling in the legs (lower extremities)
• Bluish skin discoloration
• Lump associated with a vein near the surface of the body
• Splinting of ribs with breathing (bending over or holding the chest)

Treatment of Pulmonary Embolism

Medicines: Blood thinning medicines, that is anticoagulants are given to decrease the blood's ability to form clots. They do not break up the already formed clots, however, they prevent the further enlargement of blood clots. These anticoagulants can be taken in the form of pills, injections or intravenously, through a needle inserted into the vein. Heparin and Warfarin are the usually prescribed anticoagulants. However, Warfarin is dangerous for pregnancy, thus only heparin is given to pregnant women. For patients who cannot take heparin, a new anticoagulant called Thrombin inhibitor is given.

Emergency treatment: When pulmonary embolism is severe and life threatening, the patient is immediately hospitalized. The doctors resort to definitive treatment such as thrombolytic therapy in order to dissolve the clot. Thrombolytics are medicines given to dissolve clots only in emergency situations. This is because these medicines can cause sudden bleeding. Sometimes, the doctor may try to reach the clot with the help of a catheter. The catheter is a flexible tube inserted into the upper thigh (groin) or arm through a vein to allow access to the bloodstream for treatment of the clot in the lung. Through the catheter the doctor can either extract the clot or inject medicine to dissolve the clot. Very rarely is surgery opted for, to remove the clot. Only patients suffering from recurrent embolism require to undergo surgery.

People who are at risk of pulmonary embolism must try and prevent the formation of blood clots in their bloodstream by being active. Moving around as much as possible will help prevent the formation of clots. While traveling in an airplane, one must get up every hour and walk around. During long car journeys, stop every two hours and stretch the legs and walk. Prevention is better than cure!