Most Common Causes of Pulmonary Embolism and Risk Factors to Be Aware Of
One of the leading causes of pulmonary embolism (PE) is deep vein thrombosis (DVT), a condition where blood clots form in the deep veins of the body—most commonly in the legs. When these clots break loose, they can travel through the bloodstream and become lodged in the arteries of the lungs, blocking blood flow and triggering a potentially life-threatening pulmonary embolism.
How Deep Vein Thrombosis Leads to Pulmonary Embolism
Deep vein thrombosis is by far the most frequent precursor to PE. The risk increases significantly when individuals remain immobile for extended periods, such as during long hospital stays, after major surgery, or due to prolonged bed rest. The stagnant blood flow in the lower limbs encourages clot formation, and once dislodged, these clots can quickly reach the pulmonary circulation.
Other Major Contributing Factors
Beyond DVT, several underlying medical conditions and physiological states can elevate the risk of developing a pulmonary embolism. These include:
Vascular Injury and Endothelial Damage
Damage to the inner lining of blood vessels—often caused by trauma, surgery, or catheter insertion—can trigger abnormal clotting mechanisms. This vascular injury promotes platelet activation and fibrin deposition, setting the stage for clot formation.
Blood Coagulation Disorders
Individuals with hypercoagulable states, whether inherited (such as Factor V Leiden) or acquired (like antiphospholipid syndrome), are at higher risk. These disorders cause the blood to clot more easily than normal, increasing the likelihood of both DVT and subsequent PE.
Cancer and Malignant Diseases
Tumors, especially those of the lung, pancreas, brain, and ovaries, can release pro-coagulant substances into the bloodstream. Additionally, cancer treatments like chemotherapy further disrupt normal clotting balance, making oncology patients particularly vulnerable.
Pregnancy and Postpartum Period
Pregnant women face an increased risk due to hormonal changes, reduced venous return from the lower extremities, and decreased mobility. The danger persists up to six weeks after delivery, especially following cesarean sections.
Severe Infections and Sepsis
Systemic infections can activate the body's inflammatory and coagulation pathways simultaneously. In severe cases like sepsis, widespread microclot formation may occur, raising the chance of embolic events including pulmonary embolism.
Autoimmune and Chronic Inflammatory Conditions
Diseases such as lupus, rheumatoid arthritis, and inflammatory bowel disease are associated with chronic inflammation that affects blood vessel integrity and clotting regulation, contributing to thrombotic risk.
Different Types of Pulmonary Embolism
While thromboembolism—a clot originating from a vein—is the most common type, other forms exist and are equally dangerous:
- Fat embolism: Often occurs after bone fractures, especially of the femur, where fat globules enter the bloodstream.
- Air embolism: Can result from medical procedures or trauma, introducing air bubbles into the circulatory system.
- Amniotic fluid embolism: A rare but catastrophic event during childbirth when amniotic fluid enters maternal circulation.
High-Risk Populations
Certain groups are disproportionately affected by pulmonary embolism. These include older adults (especially over 60), post-surgical patients, individuals with limited mobility, those recovering from major trauma, and people with a family history of clotting disorders. Early recognition of symptoms—such as sudden shortness of breath, chest pain, rapid heart rate, and coughing up blood—is crucial for timely intervention.
In conclusion, while deep vein thrombosis remains the primary cause of pulmonary embolism, a wide range of medical, genetic, and situational factors contribute to its development. Awareness, prevention strategies like early ambulation and anticoagulant therapy when appropriate, and prompt diagnosis are essential in reducing morbidity and mortality associated with this serious condition.