What is Sepsis – Medical Background and Warning Signs

Updated 2026-05-31

What is Sepsis – Medical Background and Warning Signs

What is Sepsis – Medical Background and Warning Signs

As we’ve noticed the medical term ‘Sepsis’ being used with increasing frequency by patients (sometimes correctly, and sometimes not), we have decided to sort out in simple terms what Sepsis is. We also aim to raise your awareness and talk about how you can recognise any potential signs.

In the most basic definition, Sepsis is a life-threatening condition caused by the body’s extreme and dysregulated response to an infection, which begins to injure its own tissues and organs.

For most of us when we develop an infection, our body recognises it and our immune system deals with it in a way that means we can recover and move on with our lives.  For some, however, our immune systems may have had to work much harder and employ more tactics in order to try and reach the status quo again, and in so doing lead us to more problems such as organ failure.

Who gets sepsis?

Sepsis can affect anyone regardless of age or sex. However, it is known that certain groups of people may be more susceptible to developing it. These are:

  • Those with weakened immune systems- for example those who are having chemotherapy or anti-rejection medications following transplants, but also those with HIV/ AIDS.  Those who have had their spleen removed are also at risk.
  • The elderly
  • Babies and young children
  • Those with pre-existing medical conditions such as diabetes mellitus, cancer, lung, kidney or liver disease
  • Those who have suffered physical trauma including burns (the skin provides a protective barrier against infection). This also includes those who have had recent surgery or procedures (this is also a trauma!)

What do I look out for?

Sepsis can develop from a wide range of infections, and can come from something considered minor or trivial such as a cut or small wound leading to a skin infection.  Common sources of sepsis are from respiratory (lung) infections like pneumonia, kidney infections and gut infections, and though these are the most common, they are by no means exclusive.  Sepsis can develop from any infection.

There is no one unifying symptom that is found in all patients with sepsis, but several
symptoms exist that make us more concerned as doctors that a person is becoming more unwell. Symptoms can be different between children and adults.

If you or someone you know have an infection and have any of the following symptoms you need to get an immediate medical opinion:

  • Change in mental status/ altered consciousness- there could be disorientation, confusion and/ or drowsiness.  There may be also be a behavioural change, especially in the elderly and in infants.
  • Fast breathing (22 or more breaths per minute in adults), or breathing that is rapid and effortful
  • Passing much less urine than usual, or no urine in the past 18 hours (or none all day)
  • Temperature less than 36 degrees Celsius
  • Fevers with shaking/ shivering episodes
  • Fast heart rate (more than 90 beats per minute, or a racing heart)
  • Low blood pressure — feeling faint, dizzy or light-headed, especially alongside any of the signs above

In any case, if you suspect you have an infection and you are either not getting better as you would expect or you are deteriorating, you should be seeking urgent medical attention.

Treatment must be instigated swiftly to give the person the best chance of survival.  Intravenous antibiotics are required to fight the underlying infection alongside other treatments such as intravenous fluids and oxygen.

Some people may have developed ‘septic shock’, whereby the sepsis process has led to them being unable to maintain their blood pressure enough for them to sustain their vital organ functions.  These people often need additional treatment and some people will need admission to an intensive care unit for a period of time for closer monitoring and treatment.

How can we try and reduce the risk of developing sepsis?

It is difficult to know if we may or may not develop sepsis if we have an infection, but there are certain things we can do to help ourselves in general:

  • Regular handwashing
  • Take any prescribed antibiotics as directed, ensuring we complete the course
  • Keeping any open wounds clean and monitoring them for any change
  • Ensuring we are up to date with our recommended vaccinations, for example, tetanus (but also recommended travel vaccinations or medications)
  • Seek early help and treatment if we have any concerns at all
  • Not taking antibiotics for viral infections or taking antibiotics that have been prescribed for others.  Intravenous antibiotics are one of our main life-saving treatments for sepsis, and with continued inappropropriate use of antibiotics, the resistance to our best antibiotics is increasing, making treatment less effective and putting lives at risk.

And finally…

Sepsis is a rapidly progressive, life-threatening condition that can lead to death if not treated urgently, and can cause lasting problems in some of those who survive.  If you have ANY concern about the health of you or someone you know in regards to this, you must speak to a professional immediately. It is best to be seen and reassured than to stay at home and suffer consequences that may not be reversible.

Sources

  1. Singer M, Deutschman CS, Seymour CW, et al. The Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3). JAMA 2016;315(8):801–810.
  2. Evans L, Rhodes A, Alhazzani W, et al. Surviving Sepsis Campaign: International Guidelines 2021. Intensive Care Med 2021;47:1181–1247.
  3. NICE. Suspected sepsis: recognition, assessment and early management. Guideline NG253, 2024.
  4. UK Sepsis Trust. The Sepsis Manual, 7th edition, 2024.
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