Sepsis is a severe illness caused by overwhelming infection of the bloodstream by toxin-producing bacteria. Sepsis is a life-threatening illness, because it causes the immune system to go into overdrive, which can overwhelm the normal processes in the blood and cause small blood clots to form. These small blood clots block blood flow to vital organs, which can lead to organ failure. Sepsis is often life-threatening, especially in people with a weakened immune system or other medical illnesses.

Sepsis is caused by a bacterial infection that can originate anywhere in the body. Common sites include:

• Kidneys (upper urinary tract infection)

• Liver or the gall bladder

• Bowel

• Skin (cellulitis)

• Lungs (bacterial pneumonia)

In hospitalized patients, common sites of infection include intravenous lines, surgical wounds, surgical drains and decubitus ulcers (pressure sores).