Both embolisms and aneurysms have similar-sounding names and can affect blood flow in the brain, but that’s where the similarities end. An embolism blocks blood flow because of a clot, while an aneurysm is when an artery breaks or twists, causing bleeding.

Discover how these two conditions can happen, how they’re connected, and what to expect if one happens to you.

An embolism is a group of particles, or clot, that breaks free from a blood vessel wall and travels through the body. It’s usually made up of clumped blood cells, fat, or cholesterol.

When these clots are first formed and still attached to the vessel wall, they are called a thrombus. Once the clot breaks free and begins to move through the body, it’s called an embolus. You may also hear your doctor refer to a clot that has detached and is moving through your body as a thromboembolism.

As an embolus travels, it can become lodged in other vessels, cutting off vital blood flow somewhere in the body. Where clots, or embolisms, travel and become lodged leads to yet another name change based on the problem the clot causes. These include:

  • Pulmonary embolism. A pulmonary embolism is an embolus that blocks a pulmonary artery in your lung.
  • Ischemic stroke. An ischemic stroke happens when an embolus has traveled to your brain.
  • Myocardial infarction. A myocardial infarction, or heart attack, is when an emboli becomes lodged in the arteries suppling blood to the heart.
  • Deep vein thrombosis. A deep vein thrombosis occurs when a large clot forms in a deep vein, usually in the legs. These clots can cause severe damage if they break free and travel to organs like the lung, heart, or brain.

An aneurysm is when an artery wall becomes weak or damaged. These weak areas can bulge, much like a balloon, and eventually burst. This often happens due to high blood pressure or atherosclerosis, which both cause the artery walls to weaken.

When an aneurysm ruptures, it causes internal bleeding, which is a medical emergency. This can happen in areas of the body including:

  • brain
  • heart
  • spleen
  • lungs
  • aorta
  • legs

When aneurysms occur in different parts of the body, they may be called other names. Examples include:

  • Abdominal aortic aneurysm. An abdominal aortic aneurysm is when the portion of your aorta that sits within the abdomen leaks or ruptures. Because the aorta carries blood to most of your body, a rupture can quickly cause massive bleeding that may be fatal. It may occur with no warning symptoms.
  • Hemorrhagic stroke. A hemorrhagic stroke occurs when there is bleeding in the brain that interrupts the flow to brain tissues.

Both conditions lead to the same effect — a disruption of blood flow. When this happens in a vital organ, like the brain or heart, the effect can be fatal.

These organs require a constant blood supply, and brain tissue can begin to die off in as little as 5 minutes without blood flow. Once brain tissue is damaged, it cannot be repaired.

The same goes for the heart. Almost immediately after blood flow stops, heart tissue begins to die off and cannot recover. The amount of overall damage to the heart depends on how much tissue was affected before blood flow was restored.

Symptoms of both aneurysms and embolisms depend on what body part is affected. Common symptoms include:

The difference between these two conditions is how they cause blood to stop flowing. With an aneurysm, a vessel can burst, causing internal bleeding. This, in turn, disrupts blood from getting to the organs. With an embolism, blood flow is blocked by a particle that’s lodged in a vessel.

Another difference is in how these conditions are treated. If you are prone to blood clots, you may be prescribed medications that thin your blood to prevent clots from forming. In the case of a large emboli, strong blood thinners like tissue plasminogen activator (tPA) can be injected to quickly dissolve the clot.

Aneurysms and embolisms both disrupt blood flow. While the cause is different, the risk factors are similar.

Risk factors common to both aneurysm and embolism include:

Aneurysms and embolisms both block blood flow in some part of your body. However, they each work in different ways. Whether your blood flow is stopped by a bleed (aneurysm) or a clot (emboli), both could be fatal if there’s a lack of blood flow to a vital organ.

If you experience symptoms that suggest either of these conditions, seek emergency care immediately.