Septic emboli are infected blood clots. They break free and travel through the bloodstream, where they get lodged and block a blood vessel.

Septic means having a systemic illness caused by an infection. An embolus is anything that moves through blood vessels until it gets stuck in a vessel that it’s too small to pass through. A septic embolus is an infected blood clot that stops the blood flow.

Septic emboli represent a two-pronged attack on your body:

  1. They completely block or partially reduce blood flow.
  2. The blockage includes an infectious agent.

Septic emboli can have mild outcomes (minor skin changes) to serious ones (life threatening infections).

Septic emboli typically originate in a heart valve. An infected heart valve can yield a small blood clot that can travel almost anywhere in the body. If it travels to the brain and blocks a blood vessel, it’s called a stroke. If the clot is from infected (septic) emboli, it’s classified as a septic stroke.

Along with a heart valve infection, common causes of septic emboli include:

The symptoms of septic emboli are similar to nonspecific signs of infection, such as:

Additional symptoms could include:

  • sharp chest or back pain
  • shortness of breath
  • fast heart rate

You’re more likely to experience septic emboli if you are more likely to get an infection. People with a higher chance of infection include:

  • older adults
  • people with prosthetic heart valves, pacemakers, or central venous catheters
  • people with compromised immune systems
  • people using injected drugs

Your doctor’s first step might be to take a blood culture. This test checks for the presence of germs in your blood. A positive culture — meaning a pathogen is detected in your blood — could indicate septic emboli.

A positive blood culture can identify the type of pathogen in your body. This also tells your doctor which antibiotic to prescribe. But it won’t identify how the microorganism entered or the location of the emboli.

Diagnostic tests to further evaluate septic emboli include:

The most common pathogen to cause a septic embolus is bacteria. Antibiotics are typically the primary treatment for septic emboli infected with bacteria.

In rarer cases, a person with a fungal infection can also get a septic embolus. This is usually treated with intravenous antifungal medications.

Depending on the location of the source of the infection, the treatment could also include the following:

  • draining an abscess
  • removing or replacing infected prostheses
  • repairing a heart valve damaged by the infection

Read on for answers to more questions about septic emboli.

Are septic emboli fatal?

Depending on how it presents, a septic embolus can lead to death. If the embolus moves from where it originally develops and blocks blood flow, it could lead to a stroke, which can be fatal. If it gets to the lungs, it can also cause respiratory failure.

Are septic emboli contagious?

Although the blood is infected when you have sepsis, you cannot transmit the bacteria to anyone. Similarly, a septic embolus is only dangerous for the person with it. Learn more about sepsis.

Are septic emboli blood clots?

Septic emboli are infected blood clots. They break away from where they formed and travel through your bloodstream until they create a blockage.

Keeping your eye out for signs of infection in your body is always a good practice, especially if you’re in a vulnerable group. Keep your doctor informed about those and other signs of illness. This can help you stay ahead of potentially serious conditions.

To head off potential infections, there are several specific preventive measures you can take:

  • Maintain good dental health.
  • Talk with your doctor about taking preventive antibiotics before dental procedures.
  • Avoid body piercings and tattoos to reduce the chance of infection.
  • Practice good handwashing habits.
  • Get prompt medical attention for skin infections.