Embolism

Symptoms of an embolism

Two of the most serious conditions caused by an embolism are:

• stroke – where the blood supply to the brain is cut off
• pulmonary embolism – where a foreign body blocks the artery that carries blood from the heart to the lungs (the pulmonary artery)

The main symptoms of a stroke are:

• drooping of the face
• weakness or numbness in one arm
• slurred speech or an inability to talk at all

The main symptoms of a pulmonary embolism are:

• chest pain – a sharp, stabbing pain that may be worse when you breathe in
• shortness of breath – which can come on suddenly or develop gradually
• coughing – this is usually dry, but may include coughing up blood or mucus that contains blood
• feeling faint, dizzy or passing out

Deep vein thrombosis (DVT), a blood clot in the deep veins of your leg, is one of the main causes of pulmonary embolisms. Sometimes it doesn't cause any symptoms. Symptoms can include:

• pain, swelling and tenderness in one of your legs (usually your calf)
• a heavy ache in the affected area
• warm skin in the area of the clot
• red skin, particularly at the back of your leg below the knee

If an artery in a limb is blocked, it causes critical limb ischaemia with the following symptoms:

• pain
• discoloured skin (either pale or blue)
• coldness
• loss of movement

When to seek medical help

Call 999 if you, or someone else has:

• pain, swelling and tenderness in a leg and develops breathlessness and chest pain - it may be a DVT that's developed into a pulmonary embolism
• if you suspect that you or someone else is having a stroke
• if you suspect that you or someone else has  a blockage in the artery of a leg or arm

Causes

A foreign body is any object or substance which shouldn't be in your blood. Foreign bodies that cause embolisms are known as emboli.

Some common causes of an embolism are below.

Blood clots

Blood contains natural clotting agents which help prevent you bleeding too much when you cut yourself.

Certain health conditions can cause blood clot in a vein (venous thrombosis) to form inside your veins even where there's no bleeding. These include:

• obesity
• heart disease
• cancer
• pregnancy

A clot can get stuck and start to block the blood flow to an organ or a limb.

Fat

A fracture to a long bone can lead to fat particles within the bone being released into the blood. Fat particles can also sometimes develop following severe burns or as a complication of bone surgery.

Air

Embolisms can occur if air bubbles enter the bloodstream.

Air embolisms are a particular concern for scuba divers.

If a diver swims to the surface too quickly, the change in pressure can cause nitrogen bubbles to form in their bloodstream and become trapped. 

This can cause decompression sickness, often called "the bends".

Divers should always be carefully monitored by their colleagues and supervisors, so any air or gas embolism can be identified and treated immediately.

Cholesterol

In people with severe Atherosclerosis (arteriosclerosis)(narrowed arteries caused by high cholesterol), small pieces of cholesterol can sometimes break away from the side of a blood vessel, resulting in an embolism.

Amniotic fluid

In rare cases, amniotic fluid – which surrounds and protects a baby inside the womb – can leak into the mother's blood vessels during labour, causing a blockage.

This can lead to:

• breathing problems
• a drop in blood pressure
• loss of consciousness

Risk factors

Your risk of getting an embolism is increased if you:

• are overweight or obese
• are pregnant
• are 60 years of age or over
• smoke
• have heart disease
• are immobile for long periods of time

Treating embolisms

How an embolism is treated will depend on:

• what caused the blockage
• the size of the blockage
• where the blockage is in the body 

A surgical procedure called an embolectomy is sometimes carried out to remove an obstruction.

Medication may be used to dissolve embolisms (thrombolysis) caused by blood clots. Anticoagulant medication can help make the blood less sticky and stop further clots forming.

Embolisms caused by air bubbles are usually treated in a hyperbaric chamber.

The air pressure inside the chamber is higher than the normal air pressure outside, which helps reduce the size of the air bubbles inside the body.

Preventing embolisms

It isn't always possible to prevent embolisms, but there are things you can do to reduce your risk, including:

• eat a healthy diet – low in fat, high in fibre, including whole grains, fruit and vegetables
• limit the amount of salt in your diet to no more than 6g (1 teaspoon) a day
• lose weight if you're overweight or obese
• stop smoking, if you smoke
• exercise for a minimum of 150 minutes a week

More useful links

• How to use your health services