Sepsis has no symptom of its own. It always looks like something else — which is why it is missed, and why one sentence from you changes what happens next.

What deterioration actually looks like

Nobody misses sepsis at the end. It is missed in the middle, when it still looks like a bad infection and the change from yesterday is the only clue. Step through these three ordinary illnesses hour by hour and watch what changes — the rate is the thing to learn.

The red flags

These are the widely used warning signs. Any one of them in someone who has, or might have, an infection means emergency assessment now.

How to check the things that matter

This page keeps saying that breathing and urine and alertness are the signals, so here is how to actually check them — and, just as important, the reassurance that most infections are only infections.

1. Count the breathing rate. Watch the chest for thirty seconds and double it, while the person is resting and not talking. Roughly: an adult sits around 12–20 breaths a minute, a school-age child 20–25, a toddler 25–35, a baby 30–40. A rate that is clearly above that range, or a number that has climbed since this morning, is one of the earliest and most useful things you can report — and it is the measurement most often skipped.
2. Count the urine. Ask when they last passed urine, and for a baby count wet nappies. Much less than usual, or none in twelve hours in a small child, or none since morning in an adult, is an organ sign rather than dehydration to be fixed with a glass of water.
3. Test alertness with a question, not an impression. Ask what day it is, or where they are, or ask a child to look at you and answer something simple. "A bit vague" is a finding; "seems tired" is not.
4. Look at the skin, undressed, in good light. Mottling or blotchiness, grey or blue lips, and cool hands and feet on a hot body are all things you cannot see through a duvet or over the phone. Press any rash with a glass or a finger and see whether it fades.
5. Write the numbers and the times down. Breathing rate, temperature, last urine, and what changed and when. Handing over three numbers and a trajectory is worth more than any adjective, and it survives the moment when you are frightened and cannot remember.

The sentence, and what to do if you are not taken seriously

Asking about sepsis by name is not being difficult. It changes how a call is triaged and what a clinician screens for, and it is exactly what patient-safety bodies ask families to do. Nobody competent is annoyed by the question.

1. Say it plainly: "Could this be sepsis?" Then give the three things that matter: what the infection is, what has changed, and how fast.
2. Lead with the change, not the symptom list. "This morning he was walking around with a cough. Now he is confused and hasn't passed urine since last night." A trajectory is far more informative than a temperature.
3. Say the risk factors out loud. Pregnancy or recent birth, chemotherapy, diabetes, no spleen, recent surgery, a catheter or a line, immunosuppressive medicines — each of these changes the threshold, and none of them will be known unless you say so.
4. If you are told it is viral or "just a bug", ask two questions. "What would make you think it was sepsis?" and "What should make me call back, and how soon?" Both are ordinary, reasonable questions, and the answers give you a plan.
5. Get the safety net in writing or in your head: what to watch for, by when, and who to call. If nobody offers one, ask for one.
6. Go back, or go elsewhere, if the person gets worse. Deterioration after a reassuring assessment is common and is not a reason to feel foolish — it is exactly what the safety net exists for. Say plainly: "she was seen four hours ago and she is worse."

The traps that catch families and clinicians alike

• A normal or low temperature. Sepsis can present cold rather than hot, especially in the very old and the very young, and a body temperature below normal is a bad sign rather than a reassuring one.
• A fever that has broken. The temperature coming down while the person gets more drowsy, more breathless or more mottled is not improvement.
• Already on antibiotics. Being on treatment does not rule sepsis out — sometimes the antibiotic is the wrong one, or was started too late, and the deterioration is happening anyway.
• Getting better and then worse again. A second deterioration after an initial improvement is a classic pattern, and it is often dismissed because the illness "was on the mend".
• Stomach symptoms. Vomiting and diarrhoea are a common way sepsis presents, and it gets called gastroenteritis — particularly in children.
• Being young and fit. Fit adults compensate well and then fall off a cliff; the absence of chronic illness is not protection, and sepsis kills healthy people in their twenties and thirties every year.
• The phone. Telephone assessment cannot see mottled skin, count a breathing rate or notice how someone looks. If you are worried and you are on the phone, say that you want them looked at in person.
• Not connecting the source. A urine infection in an older person often shows up as confusion with no pain at all, and a small wound, a leg ulcer or an infected tooth can produce sepsis without looking dramatic.

Who is at higher risk

• Babies under one, and adults over about seventy-five, especially with frailty.
• Pregnancy, birth, and the six weeks afterwards, including after miscarriage or termination. Maternal sepsis is a leading cause of maternal death and is often missed because symptoms are attributed to normal recovery.
• Chemotherapy and immunosuppression, including steroids and biologics. Many cancer units issue explicit instructions to attend hospital urgently with a fever — those instructions exist because of sepsis, and they should be followed exactly.
• Diabetes, which raises infection risk and blunts some of the warning signs, particularly in the feet.
• No spleen, or a poorly functioning spleen — a specific, high, lifelong risk with its own vaccination and standby-antibiotic plan that is worth knowing cold.
• Recent surgery, catheters, drips, drains and dialysis lines, which are direct routes into the body.
• Injecting drug use, alcohol dependence, and anything that delays presentation — the delay is often more dangerous than the underlying risk.

What happens if you go in

Knowing the shape of it makes the decision easier, and makes it easier to tell whether it is happening.

• Observations first: temperature, pulse, breathing rate, blood pressure, oxygen level and level of consciousness. A high breathing rate is one of the most useful early signals and the one most often skipped at home.
• Blood tests including a lactate, which is a marker of tissue not getting enough oxygen, plus blood cultures taken before antibiotics where possible.
• Antibiotics quickly if sepsis is suspected, along with fluids into a vein, oxygen if needed, and a search for the source — urine, chest X-ray, scans, a look at wounds and lines.
• Monitoring of urine output, because the kidneys are an early casualty and a catheter is often used to measure it.
• Being sent home is a good outcome, not a wasted trip. Assessment that finds no sepsis, with a clear safety net and a review, is the system working — and going in to be told that is exactly the right use of it.

Afterwards: the part nobody warns about

Surviving sepsis is often followed by months of being unwell in ways that surprise everybody, including the person's own family and sometimes their doctor. It has a name — post-sepsis syndrome — and knowing it exists prevents a lot of unnecessary fear and self-blame.

• Exhaustion out of all proportion to activity, muscle weakness and weight loss, often for months.
• Brain fog: poor concentration, memory lapses, difficulty with words and with decisions. It usually improves slowly.
• Sleep disturbance, low mood, anxiety, and flashbacks — an intensive-care admission is a traumatic event, and post-traumatic symptoms are common and treatable.
• Hair loss, brittle nails, altered taste, and repeated minor infections in the first months.
• Expect to need a plan, not just time: gradual increases in activity, a return-to-work conversation that assumes months rather than weeks, and a doctor who knows the history.
• Tell people what to expect. Families brace for a recovery like a broken leg's; naming the syndrome saves everybody from concluding the person is malingering or depressed when they are neither, and from missing the depression when it is genuinely there.

Preventing the infection in the first place

• Vaccination is the most effective sepsis prevention there is, because most sepsis begins as an ordinary preventable infection: influenza, pneumococcus, COVID, and the full childhood schedule including meningococcal and Hib.
• Treat wounds like wounds. Clean, cover, and look again the next day. Spreading redness, increasing pain, pus, a red streak or fever means it needs seeing rather than another dressing.
• Diabetic feet get checked daily, because a painless ulcer is a classic silent source.
• Dental infections are infections. A swollen face or jaw with fever is urgent, not a matter for next month's appointment.
• Catheters, lines and drains: hand hygiene, and a low threshold for reporting redness, pain or a new fever to whoever manages them.
• If you have no spleen or are on immunosuppression, carry the card and know the plan — including standby antibiotics if you have been given them, and the instruction to attend hospital urgently with a fever.

The drill: 16 hours

Sixteen ordinary moments — a chest infection that turned, a toddler with a fever, a new mother four days after a birth, a phone call that ended in reassurance. Most have a reasonable answer that loses hours. Pick your move; every answer explains why.

The card

Print it for the fridge. It is the one card in this series that is about a single sentence.

🖨️ Print the card