Sepsis is a reaction to severe infection. It can involve many different parts of the body. The germs causing the infection are usually bacteria, but less often can be viruses or fungi.
What is sepsis?
Sepsis is a life-threatening reaction by the body to severe infection. You may also hear severe infection being referred to as septicaemia. Strictly speaking, septicaemia is an infection of the blood, whereas sepsis refers to the whole body.
The germs involved in sepsis can be bacteria, viruses or fungi. If bacteria multiply and release poisons (toxins) into the blood, this can cause serious illness.
What is septicaemia?
Septicaemia means 'infection of the blood'. It's sometimes called 'blood poisoning'. Septicaemia occurs when germs - typically bacteria - get into the bloodstream. They can spread throughout the body, triggering widespread inflammation, which causes sepsis.
What are the symptoms of sepsis?
Not everyone will have typical symptoms. Anyone with sepsis, but especially the very old or very young and people who have problems with their immune system, can develop unusual non-specific features and this can make diagnosis more difficult.
Symptoms of sepsis in adults
Signs and symptoms of sepsis in adults include:
- Suddenly becoming confused, drowsy, or unconscious.
- Slurred speech.
- Severe breathlessness.
- Feeling cold or clammy, or having pale or mottled skin.
- Fast breathing.
- A fast heartbeat.
- Extreme shivering.
- Severe muscle pain.
- Feeling extremely unwell - including the feeling like you're going to die.
- Not passing urine for an entire day.
- Low oxygen levels (as measured with a pulse oximeter).
- Bluish colour of lips and tongue (cyanosis).
People with sepsis often have one or more symptoms of infection. These symptoms also happen in people without sepsis. They include:
Symptoms of sepsis in children
Young people aged over 12 years tend to react in a similar way to adults - as above.
Children aged 12 or younger may be more difficult to assess than adults. Infections, usually viral infections, are very common in children and sepsis is rare. The signs of serious illness - like sepsis - in children can be difficult to spot, and can change over time.
Children with sepsis may:
- Have a very high temperature.
- Feel abnormally cold to touch.
- Have patchy (mottled) skin and bluish colour to the skin (or just the lips and tongue), or may have very pale skin.
- Have a rash that does not fade with pressure.
- Breathe more quickly than usual.
- Be very tired, drowsy, and difficult to wake up from sleep.
- Unexplained change in behaviour.
- Have a 'fit' or convulsion.
Young children may not want feeds, may repeatedly be sick (vomit) or may not pass any urine for 12 hours or more and so not have wet nappies.
Like in adults, children with sepsis often have other symptoms of infection as well.
How common is sepsis?
About 1 in 500 people develop severe sepsis in England every year. The number is much higher in developing countries.
Who is at risk of sepsis?
- The elderly (those aged over 75 years) and the very young (especially if aged less than 1 year).
- People who have had surgical procedures.
- People with indwelling lines or catheters.
- People who drink alcohol excessively.
- People who inject recreational drugs.
- People who have diabetes mellitus.
- People who have had severe burns.
- People who have problems with their immune system (the bodily system that fights infection).
- Medications - eg, high doses of steroids, some medicines to treat cancer.
- Pregnant women.
How do you develop sepsis?
Rarely, a germ overcomes the body's immune system, resulting in sepsis. No one knows why this happens but there are various theories. It is not clear why a few people are prone to serious illness and many other people are carriers of the same germ but have no ill effect.
Usually the germs are bacteria but sometimes they can be viruses or fungi. Studies suggest that the level of steroids in the body, the effects of various other chemicals and hormones and the way the body's cells handle invading germs may all be involved.
What is the treatment for sepsis?
Sepsis is a medical emergency and treatment needs to be started as soon as possible. Always seek urgent medical advice or get straight to hospital if you think you or someone close to you may have sepsis.
- If you develop sepsis you can become severely ill. You will need to be admitted to hospital and may need to be admitted to an intensive care unit.
- You will usually be given strong antibiotics through a drip to treat the infection that's causing sepsis.
- You will usually be given fluids through the drip.
- You may require oxygen to support your breathing.
- In severe cases, you may need special treatments that can only be given in intensive care, such as drugs to raise your blood pressure if it is dangerously low.
- If sepsis is caused by an abscess (collection of pus), an operation might be needed to drain it and remove the source of the infection.
What is the outlook for sepsis?
The outlook for sepsis can be good if it is diagnosed and treated early. However, without early treatment, between 10 and 50 people out of 100 will die, depending on the severity of sepsis. Older people tend to fare less well, especially if they have a long-term illness like diabetes or heart disease.
Complications can include:
- Disseminated intravascular coagulation - this means the formation of blood clots in the small blood vessels throughout the body.
- Failure of the adrenal glands (the glands that sit on top of the kidneys that produce adrenaline, steroids and other important body chemicals).
- Multiorgan failure - this means that several organs of the body stop working properly. These can include the heart, lungs and kidneys.
As with any severe illness which needs intensive treatment in hospital, people recovering from sepsis may experience physical and psychological difficulties and these difficulties may last for several years.
Physical problems may include feeling very tired, muscle weakness, feeling short of breath, chest pains, fluid swelling (oedema), joint pains, poor appetite, disturbed vision, skin numbness or pins and needles, and frequent illness caused by further infections.
Psychological difficulties may include feeling anxious, feeling low or depressed, nightmares, poor sleep, poor concentration and problems with memory.
Can sepsis be prevented?
Maintaining a healthy lifestyle will reduce your chances of developing infections that can lead to sepsis. Both smoking and alcohol increase the risk.
If you have a condition which qualifies you for influenza immunisation and pneumococcal immunisation jabs (for example, if you have diabetes or asthma) make sure you take up these options. Children need to be up to date with their vaccinations, particularly Haemophilus influenzae type b (Hib), group C meningococcus, pneumococcus and mumps (part of the MMR vaccination).
Further reading and references
Sepsis - recognition, diagnosis and early management; NICE Guideline (July 2016 - updated January 2024)
Sepsis; NICE Clinical Knowledge Summary. Last revised December 2023.
Fever in under 5s: assessment and initial management; NICE Guidance (last updated November 2021)