Immunity and infection prevention

What is sepsis

The main article (“What is sepsis?”) gives the general idea of sepsis. This topic looks more deeply at sepsis in people with leukaemia: why it develops faster, which signs to watch for and what is done in hospital.

Last updated: 14 October 2026~1 min read

A silhouette with spreading glow. — **Figure 1.**Infection spreads through the whole body.

01Short answer

Sepsis is when the body’s response to infection gets out of control and damages its own organs. Any infection can turn into sepsis. In leukaemia, especially during neutropenia, sepsis can develop faster and with fewer warning signs. Warning signs include: confusion or slurred speech, very fast breathing, a fast heartbeat, low blood pressure and dizziness, mottled or pale skin, passing much less urine, and a feeling that something is badly wrong. Sepsis needs emergency treatment: fluids into a vein, antibiotics started quickly and, if needed, intensive care. Seeking help early makes a real difference.

02Simple explanation

Sepsis: an uncontrolled response to infection.

During neutropenia it develops faster.

Hours matter.

03Scientific explanation

Organ damage: sepsis disrupts the kidneys, lungs, heart and brain; in septic shock, blood pressure stays low despite fluids.

Global burden: the WHO calls sepsis a leading cause of death worldwide and stresses early recognition.

04What happens in the body?

Spreading through the body

An infection that starts in one place becomes a whole-body response.

Warning signs

Confusion, fast breathing, mottled skin: get help at once.

Six simple icons in a row. — **Figure 2.**Six warning signs of sepsis.

Intensive care

When needed, treatment in intensive care supports the organs.

A bedside with a monitor and drip. — **Figure 3.**Calm treatment in intensive care.

05How sepsis develops

Four steps.

1InfectionStarts in one place.

2ResponseThe whole body reacts.

3OrgansOrgans weaken.

4TreatmentStarts fast.

06Warning signs of sepsis

Sign	What it means
Confusion	The brain is short of blood flow
Very fast breathing	The body is seeking oxygen
Mottled or pale skin	Circulation is disturbed
Little urine	The kidneys are weakening
Dizziness	Blood pressure is low

07Key terms

Sepsis: An uncontrolled response to infection with organ damage.
Septic shock: Persistently low blood pressure in sepsis.
Lactate: A test reflecting disturbed circulation.
Intensive care: A unit for very serious illness.
Intravenous fluid: Fluid given into a vein.

08Key points

Sepsis is life-threatening.
It develops fast in neutropenia.
Confusion and fast breathing are danger signs.
Antibiotics and fluids start quickly.
Seeking help early improves outcomes.
Ask: “Could this be sepsis?”

09Frequently asked questions

What happens after sepsis?

Recovery takes time; tiredness and weakness can last for weeks.

What should I say to the doctor?

“I have neutropenia; could this be sepsis?”

Can sepsis be prevented?

Seeking help early for fever, hygiene and vaccines lower the risk (“Preventing infection”).

10Questions for your doctor

Take these questions to your appointment. The ones you save are collected on the “My questions” page and stay on this device only.

What happens after sepsis?
What should I say to the doctor?
Can sepsis be prevented?

My questions

12Sources

World Health Organization (WHO). Sepsis (fact sheet)
NHS. Sepsis
MedlinePlus (U.S. National Library of Medicine). Sepsis
MedlinePlus (U.S. National Library of Medicine). Fever
MedlinePlus (U.S. National Library of Medicine). Fungal Infections
MedlinePlus (U.S. National Library of Medicine). Mouth and Teeth
NHS. Vaccinations
InformedHealth.org (IQWiG). How does the immune system work?
National Cancer Institute (NCI), SEER Training. Lymph Nodes
National Cancer Institute (NCI), SEER Training. Spleen

Medical disclaimerThis information is for educational purposes only and does not replace medical advice.

Last updated: 14 October 2026← Back to the list

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