HomeHealth TopicInfections

How Does a Person Get Sepsis From an Infection?

Kelly Elterman, MDSophie Vergnaud, MD
Written by Kelly Elterman, MD | Reviewed by Sophie Vergnaud, MD
Published on December 9, 2021

Key takeaways:

  • Sepsis is a life-threatening condition caused by an extreme reaction of the immune system to an infection. 

  • Any kind of infection can cause sepsis, but some people are at higher risk.

  • Sepsis requires immediate treatment in a hospital. Even with treatment, though, sepsis can lead to serious long-term medical problems.

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MarkHatfield/iStock via Getty Images

Sepsis is a life-threatening and life-changing condition caused by a widespread infection in your body. Every year, 1.7 million people in the U.S. get sepsis, and 270,000 die. An infection in any part of your body can lead to sepsis, and it can happen to anyone. The whole-body inflammation in sepsis can lead to life-threatening changes in heart function and blood pressure. 

If that sounds scary, it’s because it is. Sepsis is a medical emergency. The faster you get care for it, the better your chances of recovery. Luckily, healthcare providers are well-trained to recognize the signs in people who get to the hospital. We’ll share those with you here so that you can act fast if you notice the early signs of sepsis.

What is sepsis? 

Sepsis is a medical emergency. It happens when an infection triggers an extreme immune system response that affects cells and organs throughout the body. Without treatment, sepsis  can cause the vital organs in the body to shut down. 

You may have heard of the word septicemia, but that’s something slightly different: 

  • Septicemia, also known as blood poisoning, is when there is an infection in the bloodstream. This blood infection can be caused by any microbe (bacteria, virus, or fungus), and it can come from anywhere in the body. Commonly, infections come from the skin, urine, bowel, or lungs. Septicemia can cause sepsis, though not always.

  • Sepsis, on the other hand, is not an infection. It is an uncontrolled, whole-body response to an infection. It can follow septicemia, but it can also happen even if an infection hasn’t traveled to the bloodstream. 

The whole-body inflammation in sepsis causes blood pressure to drop and pushes the heart into overdrive. Without treatment, there isn’t enough blood pressure to fuel the body’s vital organs. This is septic shock. Septic shock can cause heart failure, lung failure, kidney failure, and coma (brain failure). Sepsis can also cause problems with blood clotting —  from small blood clots all over the body to uncontrolled bleeding.       

How does infection cause sepsis?

Normally, the immune system works to fight against invading microbes. But sometimes, the immune system overreacts to the infection, causing a dangerous chain reaction throughout the body that eventually causes it to shut down. This is sepsis. Researchers do not yet know exactly why sepsis happens to some people, but they do know who is at higher risk.

Who gets sepsis?

Anyone with any kind of infection can develop sepsis. But some people with certain underlying medical conditions are at higher risk than others: 

  • Infants, under the age of 1 year

  • Older adults over the age of 65 years 

  • People with cancer 

  • People with diabetes

  • People with chronic lung disease

  • People with kidney disease

  • People with a weakened immune system, such as from immune-suppressing medications, immune system diseases, or pregnancy

  • People who have had sepsis before

  • People who have had a recent hospitalization

How can you tell if someone has sepsis?

The early signs of sepsis can be vague and difficult to spot. They may not be very different from the symptoms of any other run-of-the-mill infection. The important thing to keep in mind is that any infection in any person can cause sepsis — especially if that person is at high risk. 

Warning signs of sepsis

If or when sepsis does develop, you’ll want to recognize the signs and act fast to get medical help.

The Sepsis Alliance boils it down to four signs of sepsis to be on the lookout for:

  • Temperature: higher or lower than normal

  • Infection: any symptoms of an infection, such as a cough; a red, painful skin swelling; or burning with urination

  • Mental change: confusion, sleepiness, drowsiness

  • Extremely ill: discomfort, severe pain, breathlessness

In the hospital, there are tests and checks that healthcare providers can carry out very quickly to diagnose sepsis. The Sepsis Alliance also recommends that you say the words, “I’m concerned about sepsis, because I have…,” to healthcare professionals to make sure you get the care you need quickly. 

Be aware that symptoms of sepsis can be different for different people, and not all people will have all of the symptoms. In older people especially, sepsis can happen without obvious signs or symptoms of an infection. And in children, the warning signs of sepsis can look quite different, too.  

How is sepsis diagnosed?   

Here are some checks and tests you can expect from a healthcare provider if they think you have sepsis: 

  • Regular and frequent blood pressure and heart rate checks

  • Regular and frequent temperature and pulse oximetry (oxygen level) checks

  • Blood draws to look at white blood cells, infection and inflammation markers, kidney function, liver function, blood clotting, and blood grouping (in case you need a blood transfusion) 

  • A top-to-toe physical examination to look for infection

  • Imaging tests, such as a chest X-ray, an ultrasound scan of the abdomen, and/or a CT scan

  • An electrical tracing of the heart (EKG)

  • A urinary catheter to collect urine for infection testing and to measure how much urine you are producing (a sign of how well the kidneys are working)

Doctors may also need to rush to get thin plastic tubes (intravenous lines) into the veins and arteries of the arms, and sometimes the neck. This allows for:

  • More precise blood pressure measurements

  • Easier blood draws to monitor organ function

  • Large doses of medications to be given to treat the infection and the sepsis    

Sometimes, other invasive procedures, like a lumbar puncture, may be necessary if it is possible that meningitis could be the cause. 

Can sepsis have complications?

Left untreated, sepsis can lead to severe sepsis and septic shock, both of which can cause serious immediate and long-term complications. 

Severe sepsis requires treatment in an intensive care unit, or ICU. Up to 30% of people with severe sepsis die from it.

Even if people survive sepsis, there can be long-term risks and complications

  • As many as half of sepsis survivors may develop post-sepsis syndrome, a chronic condition that can have many physical and psychological symptoms, such as flashbacks, panic attacks, depression, and difficulty concentrating. 

  • One-third of sepsis patients die within the first year from physical complications. 

  • One in six survivors may develop chronic weakness, fatigue, mental fog, or difficulty concentrating. 

The good news is that roughly half of sepsis survivors go on to recover without any long-term problems. 

What are the treatments for sepsis?

Sepsis treatment requires hospitalization and may involve different types of medications, including intravenous fluids, blood transfusions, antibiotics, antivirals, antifungals, and medications to support the heart and blood pressure. More serious cases may also need kidney dialysis, or a breathing tube and ventilator. Some people may even need surgery to remove infected tissue. 

The chances that treatment will be successful depend on how severe the sepsis is by the time you get to a hospital. In some severe cases, sepsis may not respond to treatment. In other cases, treatment may improve sepsis, but long-term complications can still develop.

The bottom line

Sepsis is a serious, life-threatening condition that needs immediate medical care. Any infection can lead to sepsis, but some people are at higher risk than others. Sometimes, sepsis can happen without obvious signs of infection, so if you feel unwell and you think you may have sepsis, get care right away. Treatment for sepsis includes IV fluids, antibiotics, antivirals, antifungals, and sometimes medications to help the blood pressure. Even with treatment, sepsis may lead to serious long-term medical problems.


Centers for Disease Control and Prevention. (2021). What is sepsis?

Johns Hopkins Medicine. (n.d.). Lumbar Puncture.

View All References (9)

National Library of Medicine. (2021). Sepsis.

Nemours Kids Health. (2018). Sepsis.

Prescott H., et. al. (2018). Postsepsis Morbidity. Journal of the American Medical Association.

Sepsis Alliance. (n.d.). Risk Factors.

Sepsis Alliance. (n.d.). Severe Sepsis.

Sepsis Alliance. (n.d.). Symptoms.

Sepsis Alliance. (2021). Blood Poisoning.

Sepsis Alliance. (2021). Post-Sepsis Syndrome.

Sepsis Alliance. (2021). What is Sepsis.

GoodRx Health has strict sourcing policies and relies on primary sources such as medical organizations, governmental agencies, academic institutions, and peer-reviewed scientific journals. Learn more about how we ensure our content is accurate, thorough, and unbiased by reading our editorial guidelines.

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