Pulmonary Embolism – Symptoms and Causes

Overview

A pulmonary embolism occurs when a blood clot lodges in an artery in the lung, blocking blood flow. Most commonly, these clots form in a deep vein in the leg before traveling to the lungs.

This initial formation of clots in deep veins is called deep vein thrombosis (DVT). Pulmonary embolisms can be dangerous and potentially life-threatening conditions. The blockage prevents normal blood flow and oxygen exchange in the lungs.

Key facts about pulmonary embolism:

• Usually begins as a blood clot in the leg
• Can form in other body veins (though less common)
• Requires immediate medical attention
• Has significantly better outcomes with prompt treatment
• Can be prevented with proper measures to reduce blood clot formation

With quick medical intervention, the survival rate for pulmonary embolism improves dramatically. Prevention strategies focus on reducing the risk of developing blood clots in the legs.

Signs of Pulmonary Embolism

Pulmonary embolism causes different symptoms based on clot size, lung area affected, and your overall health. Many people experience these common warning signs:

• Sudden breathing difficulty that occurs even at rest and worsens during activity.
• Sharp chest pain that intensifies when breathing deeply, coughing, or changing positions.
• Fainting episodes (syncope) from sudden drops in heart rate or blood pressure.

You might also notice:

• Coughing up blood or bloody mucus
• Fast or uneven heartbeat
• Dizziness or feeling lightheaded
• Heavy sweating
• Fever
• Swelling or pain in one leg, typically the calf
• Bluish skin tone (cyanosis)

When to Get Medical Help

Don’t wait if you have trouble breathing, chest pain, or fainting spells. These could signal a life-threatening pulmonary embolism that requires immediate medical care. Prompt treatment significantly improves your chances of recovery.

If you have risk factors such as recent surgery, prolonged inactivity, or a history of blood clots, watch for warning signs.

What Causes Pulmonary Embolism

Pulmonary embolism happens when material gets stuck in a lung artery, blocking blood flow. Most often, this blockage comes from blood clots that form in the deep veins of the legs, a condition called deep vein thrombosis.

When these clots break loose, they can travel through the bloodstream to the lungs. Many cases involve multiple clots, not just one.

When an artery becomes blocked, the part of the lung it supplies may die from lack of blood. This is called pulmonary infarction.

Besides blood clots, other materials can sometimes block lung arteries:

• Fat released from broken bones
• Pieces of tumors
• Air bubbles

These blockages make it harder for your lungs to deliver oxygen to your body. Without proper blood flow through the lungs, oxygen levels can drop dangerously low in your bloodstream.

Risk Factors

Past Blood Clot History

If you or a close blood relative, such as a parent or sibling, has experienced venous blood clots or pulmonary embolism before, your risk is significantly higher. This family history can indicate genetic factors that affect how your blood clots.

Health Conditions and Medical Treatments

Several health issues can raise your risk of developing dangerous blood clots:

• Heart Problems: Heart failure and other cardiovascular diseases make blood more likely to clot abnormally.
• Cancer: Certain types of cancer increase clotting risk, particularly:
  • Brain
  • Ovary
  • Pancreas
  • Colon
  • Stomach
  • Lung
  • Kidney
  • Metastatic cancers (those that have spread)

Cancer treatments like chemotherapy further increase this risk. Women with personal or family histories of breast cancer taking medications such as tamoxifen face higher risks as well.

Surgical Procedures

Surgery is a leading cause of problematic blood clots. Doctors often prescribe preventive medications before and after major operations like joint replacements.

Clotting Disorders

Some inherited conditions affect blood clotting processes. Kidney disease and other medical conditions can also increase clot formation risk.

COVID-19

People with severe COVID-19 symptoms face higher pulmonary embolism risks.

Reduced Movement Periods

Blood clots form more easily during times when you move less than usual:

• Bed Rest: Being confined to bed after surgery, a heart attack, a leg fracture, or serious illness increases the risk. When legs remain flat for extended periods, blood flow slows and can pool in the legs, potentially forming clots.
• Travel: Sitting in cramped positions during long flights or car trips reduces normal blood circulation in the legs, raising clot risk.

Additional Risk Factors

Several other factors can increase your chance of developing blood clots:

• Tobacco Use: Smoking increases clot risk, especially in people with other risk factors, though scientists don’t fully understand why.

• Excess Weight: Being overweight raises blood clot risk, particularly when combined with other risk factors.

• Hormonal Treatments: The estrogen in birth control pills and hormone replacement therapy can increase blood clotting factors, especially in smokers or those carrying extra weight.

• Pregnancy: A baby’s weight pressing against pelvic veins can slow blood return from the legs. When blood moves more slowly or pools, clots form more easily.

Complications

Pulmonary embolism can be deadly if not detected and treated quickly. Without proper diagnosis and treatment, about one-third of patients don’t survive. However, prompt medical attention greatly reduces this risk.

One serious complication is pulmonary hypertension. This condition develops when:

• Blood pressure in the lung arteries becomes too high
• The right side of the heart experiences excessive pressure
• The heart must work harder to push blood through blocked vessels

Over time, this extra strain can weaken the heart muscle and affect its ability to function properly.

In some uncommon situations, tiny blood clots (emboli) may remain in the lungs permanently. These can cause scarring in the pulmonary arteries, which restricts normal blood flow.

This damage can lead to a long-term condition called chronic pulmonary hypertension, which creates ongoing health challenges.

Ways to Prevent Blood Clots

The risk of developing blood clots during travel is relatively low. However, this risk increases with longer journeys.

Several simple strategies can help prevent blood clots while traveling:

Stay Hydrated

• Drink plenty of water throughout your journey
• Avoid alcoholic beverages, which can cause dehydration

Move Regularly

• Walk around the airplane cabin every hour
• During road trips, stop periodically to stretch and walk
• Try a few deep knee bends when possible

Exercise While Seated

• Make circular motions with your ankles
• Raise and lower your toes every 15–30 minutes
• Flex and extend your calf muscles

Consider Compression Stockings

• These special stockings promote better blood flow
• They come in various styles and colors
• Ask your doctor if these would be helpful for you
• Special devices called “stocking butlers” can help you put them on

Healthcare providers often recommend these preventive measures. They help blood circulate properly through your legs and prevent blood from pooling. This prevents dangerous clots that could travel to your lungs.

Other effective prevention methods include blood-thinning medications (especially before and after surgery), leg elevation, and physical activity.

Raising the foot of your bed 4–6 inches with blocks can help blood flow while you sleep. It’s important to start moving soon after surgery, even if it’s uncomfortable at first.

For people at higher risk, pneumatic compression devices might be used. These special cuffs wrap around your legs and automatically inflate and deflate, creating a gentle massaging action that improves blood flow.