Thanks to Nottingham University medical student Catarina Soares for researching and putting this piece together. Have a read of Catarina’s other pieces discussing The Dietfits Study and the persistent diet-myth about whether fruit is for “bad” here.
It isn’t difficult to find countless headlines and scare stories about sepsis – or any illness, for that matter. But what exactly is sepsis, and why should we be worried about it?
What is sepsis?
Sepsis is defined as a life-threatening organ dysfunction caused by an overwhelming response to infection (1,2). When we get an infection, our body triggers a defence mechanism, the inflammatory response, to fight off the bug or toxin. This inflammatory response can sometimes be so strong that our immune system causes harm to our own body: collateral damage in the fight against the infection.
It’s important to highlight the difference between a ‘bad infection’, sepsis, and septic shock. Sepsis is when the body’s response to infection (not the bacteria themselves) damages the tissues and organs, making it more serious than an infection alone, and septic shock is a very severe form of sepsis (2). An infection is caused by a bacteria or other bug that enter the body and cause damage or disease, and although it causes inflammation, it does not always lead to sepsis.
How does sepsis affect the body?
A very strong inflammatory response can do us harm by interfering with the body’s ability to function normally. During the inflammatory response, some of the chemicals released make the blood vessels leakier for the white blood cells (that fight infection) to get to the bacteria. However this process can also make the blood pressure fall. A drop in blood pressure subsequently reduces blood flow to vital organs, which means they don’t get enough oxygen to work properly, which leads to organ dysfunction.
Inflammation also acts a little like a domino effect: once it is triggered, it recruits more and more cells through the release of chemicals. Although there are also some molecules that are anti-inflammatory to help regulate this response, in sepsis the balance is tipped towards inflammation (2).
Another effect of widespread inflammation is the activating of blood clotting molecules, which causes coagulation of blood. This process can block small blood vessels, also leading to organ damage (3).
What causes sepsis?
It can be brought on by different kinds of infection, like pneumonia, skin or wound infections, meningitis, or the flu. As it’s associated with infections, those with a more fragile immune system are at a greater risk of developing sepsis – a bigger, more widespread infection is more likely to trigger the immune system into overdrive (4).
What are the symptoms of sepsis?
A blood test may be needed to know if someone has sepsis, but there are screening tools which give healthcare professionals clues to the diagnosis (1).
When blood pressure drops, the body has an automatic response to try bring it back up or getting the nutrients and oxygen where they’re needed. To do this, the heart starts pumping faster and the breathing rate increases. This means that people with sepsis will often have a fast heart rate and a fast breathing rate, in addition to low blood pressure (1). They may also have a fever (above 38ºC), which is part of the body’s reaction to fight infection, or they may have a very low temperature (less than 36ºC) (1,5).
In cases of severe sepsis, and septic shock, other symptoms can include confusion or disorientation, a significant decrease in urine output, rashes (that don’t disappear when pressed on), or cold and clammy skin (1,2,5).
Blood tests give us more information about how unwell someone is. Two key tests doctors check as part of the sepsis pathway are the white blood cell count (WBC) and lactate. However, other blood tests, microbiology tests, and imaging are ordered too, to paint a complete picture of what is wrong.
How is it treated?
If doctors suspect sepsis, they start a treatment plan known as Sepsis Six (1,6):
- Give oxygen
- Do some blood tests
- Give antibiotics
- Give fluids
- Measure urine production
- Blood cultures (to try find any bugs in the blood)
This fights the infection in the best way possible: first doctors start with broad antibiotics that can kill most bugs, and try to find out which bacteria is causing the illness so that at a later stage, antibiotics that are more targeted to that bacteria can be used. Measuring urine production and doing blood tests allows doctors to monitor the patient’s progress, to know how poorly they are, and whether they’re getting better. The fluids and oxygen are supportive measures – they keep the blood pressure up and oxygen levels high to help the body recover until it’s well enough to do that on its own.
Should I be afraid?
It’s not something you need to worry about every time you get an infection but knowing NHS advice is helpful in case you’re ever worried that you or someone you know may have sepsis – particularly those who are at greater risk.
- You should call 999 or go straight to A&E if a child looks mottled, bluish or pale; is very lethargic or difficult to wake; feels abnormally cold to touch; is breathing very fast; has a rash that does not fade when you press it; or has a fit or convulsion (4,5). If the child is under 5 and not feeding, is vomiting repeatedly or hasn’t had a wee or wet nappy for 12 hours, and you’re worried they’re getting worse, call 111 or see your GP (5).
- Women who are pregnant, or have recently given birth, had a miscarriage or a termination of pregnancy are a high risk group for sepsis. The signs and symptoms are similar, but may be less obvious – so it’s important to be aware of them (5).
- People who have a compromised immune system (such as those undergoing chemotherapy) are another high-risk group. These patients are given advice by their doctors to be in contact if their temperature goes over 38ºC (2).
If you’ve recently had an infection or injury, and think you may have the early signs of sepsis, follow NHS advice and ring 111 for further guidance (4).
Although sepsis is dangerous, it is also treatable – especially when picked up early. Doctors and other healthcare professionals undergo a lot of training in order to recognise and treat sepsis. There are also a great deal of public education measures to make sure people are informed about what symptoms to look out for, especially those at a higher risk. I couldn’t put it any better than the UK Sepsis Trust – if you’re worried, just ask: “could it be sepsis?”.
(1) Kumar P, Clark M. Clinical Medicine [Internet]. 9th ed. Elsevier; 2016 [cited 2018 Sep 29]. Available from: https://ebookcentral.proquest.com/lib/nottingham/reader.action?docID=4676140&query=
(2) Nutbeam T, Daniels R. The Sepsis Manual. 4th ed. Birmingham: United Kingdom Sepsis Trust; 2018.
(3) Septic Shock. Practice Essentials, Background, Pathophysiology 2018. [cited 2018 Oct 18]. Available from: https://emedicine.medscape.com/article/168402-overview#a4
(4) Sepsis – NHS [Internet]. [cited 2018 Sep 30]. Available from: https://www.nhs.uk/conditions/sepsis/
(5) Bacterial Sepsis in Pregnancy. Royal College of Obstetricians & Gynaecologists; 2012.
(6) Wilkinson IB, Raine T, Wiles K, Goodhart A, Hall C, O’Neill H. Oxford Handbook of Clinical Medicine. 10th ed. 1985.