Nid yw'r tudalen hwn ar gael yn Gymraeg ar hyn o bryd. Dyma'r fersiwn Saesneg.


Sepsis is a life-threatening illness caused by the body’s immune system overreacting to an infection. It is estimated that there are over 30,000 cases of severe sepsis in the UK every year. Sepsis occurs in three stages:

Uncomplicated sepsis caused by infections, such as influenza or dental abscess. This is very common and does not usually require hospital treatment and a full recovery is made.
  • Severe sepsis occurs when the body’s response to infection has started to interfere with the function of vital organs, such as the heart, kidneys, lungs or liver.
  • Septic shock occurs in severe cases of sepsis, when blood pressure drops to a dangerously low level, preventing vital organs from receiving enough oxygenated blood.

Sepsis is often referred to as either blood poisoning or septicaemia, although sepsis is not just limited to the blood and may affect the whole body, including the organs.

Septicaemia refers to a bacterial infection of the blood, whereas sepsis can also be caused by viral or fungal infections.

If sepsis is not treated, it can progress from uncomplicated sepsis to septic shock. Severe sepsis and septic shock are medical emergencies and normally require admission to an intensive care unit and approximately 30-50% will die because of the condition. Factors influencing outcome include the age and health status of the ill person and the nature and source of the infection.