How Serious Is a Clot on the Lung?

Symptoms of a clot on the lung (pulmonary embolism) include:

• Panting
• Shortness of breath
• Difficulty breathing
• Sharp, knife-like chest pain when inhaling or straining
• Cough, including coughing up blood
• Rapid heartbeat

A clot on the lung (pulmonary embolism) is a medical emergency that can lead to death if not treated promptly. If you experience any symptoms, especially if they occur over a short period of time (hours or days) or worsen rapidly, call 9-1-1 and get to a hospital’s emergency department immediately. Do not drive yourself. 

There are a number of possible causes for a clot on the lung (pulmonary embolism), such as: 

• Loss of vein function (venous stasis)
• Conditions in which a person is more likely to develop blood clots (hypercoagulable states)
  • Certain diseases
  • Obesity
  • Trauma
  • After surgery
• Genetic factors
  • Factor V Leiden mutation 
  • Primary or acquired deficiencies in protein C, protein S, and antithrombin III 
• Immobilization
  • Prolonged bed rest 
  • Immobilization of a limb in a cast
  • Long haul travel 
• Surgery and trauma
• Pregnancy
• Oral contraceptives and estrogen replacement
• Cancer (malignancy), especially 
  • Pancreatic carcinoma
  • Bronchogenic carcinoma
  • Carcinomas of the genitourinary tract, colon, stomach, and breast
• Hereditary factors
  • Antithrombin III deficiency
  • Protein C deficiency
  • Protein S deficiency
  • Factor V Leiden (most common genetic risk factor for thrombophilia)
  • Plasminogen abnormality
  • Plasminogen activator abnormality
  • Fibrinogen abnormality
  • Resistance to activated protein C
• Acute medical illness
• AIDS (lupus anticoagulant)
• Behçet disease
• Congestive heart failure (CHF)
• Heart attack (myocardial infarction)
• Polycythemia
• Systemic lupus erythematosus
• Ulcerative colitis

Other risk factors for developing a clot on the lung (pulmonary embolism) include:

• Chronic obstructive pulmonary disease (COPD)
• Drug abuse with intravenous (IV) drugs
• Drug-induced lupus anticoagulant
• Heart failure
• Hemolytic anemias
• Heparin-associated thrombocytopenia
• History of thrombophlebitis 
• Homocystinemia
• Homocystinuria
• Hyperlipidemias
• Phenothiazines
• Thrombocytosis
• Varicose veins
• Venography
• Venous pacemakers
• Warfarin (first few days of therapy)
• Inflammatory bowel disease (IBD)
• Prior pulmonary embolism
• Sleep-disordered breathing 
• Smoking
• Stroke, paresis, or paralysis

A clot on the lung (pulmonary embolism) is diagnosed with a patient history and physical examination. Tests used to help diagnose a clot on the lung include:

• D-dimer blood test 
• Computerized tomography pulmonary angiogram (CT-PA) 
• A ventilation/perfusion lung scan (also called a V/Q scan) 
• Pulmonary angiography 
• Magnetic resonance imaging pulmonary angiography (MRI-PA) 

Treatment for a clot on the lung (pulmonary embolism) includes medications called anticoagulants (blood thinners) to keep clots from getting bigger. Most of the time, a blood clot in the lung is first treated in the hospital.

Once a clot in the lung has been found, patients are prescribed medication to reduce the risk of developing future blood clots. These medications are usually prescribed for at least three months or longer to give the body time to dissolve the old clot. People who have a blood clot are at risk of developing another clot, especially in the first few months after diagnosis, so it’s important to take the medications to prevent clots from getting bigger and new ones forming. Sometimes an injection of a medication called heparin is given first. 

Medications used to treat a clot on the lung and prevent new clots from forming include: 

• Apixaban (Eliquis)
• Dabigatran (Pradaxa)
• Edoxaban (Savaysa, Lixiana)
• Rivaroxaban (Xarelto)
• Warfarin (Coumadin, Jantoven)

Take medications exactly as prescribed. Patients will need to get regular blood tests to check how the blood is clotting. 

For patients unable to take medicines to prevent and treat clots, or who do not get enough benefit from the medicines, an inferior vena cava filter (also called an IVC filter) may be indicated.

This is a filter placed inside the large vein that carries blood from the legs and the lower half of the body back up to the heart (the vena cava) to filter and trap any large clots that form below the location of the filter. An IVC filter may be recommended for patients who: 

• Are not able to safely take medication for blood clots
• Form clots even while taking a medicine for blood clots
• Have a dangerous bleeding problem while taking a medicine for blood clots
• Are so sick another blood clot in the lung (pulmonary embolism) could be fatal

In severe cases, a clot in the lung can cause low blood pressure and even shock, and the body's organs and tissues are not able to get enough blood supply. In this case, “clot-busting” medicine may be given through a catheter. In other cases, surgery may be performed to remove the clot.

There are cases in which blood clots may be prevented, for example, in people who sit still for too long, such as on a long-haul flight. 

Some tips to help prevent a blood clot during a long airplane flight include: 

• Do not smoke just before the trip
• Wear loose, comfortable clothing for the flight
• Wear knee-high compression stockings
• Shift position while seated, and move the legs and feet often
• Stand up and walk around every 1 to 2 hours 
• Avoid alcohol and medicines that cause drowsiness, because they can hinder the ability to move around