Sepsis is a severe illness in which the bloodstream is overwhelmed by bacteria.

Sepsis is caused by a bacterial infection that can begin anywhere in the body. Common places where an infection might start include:

• The bowel (usually seen with peritonitis)
• The kidneys (upper urinary tract infection)
  • The liver or the gall bladder
• The lungs (bacterial pneumonia)
• The skin (cellulitis)

Sepsis may also accompany meningitis. In children, sepsis may accompany infection of the bone (osteomyelitis). In hospitalized patients, common sites of infection include intravenous lines, surgical wounds, surgical drains, and sites of skin breakdown known as bedsores (decubitus ulcers).

The infection is often confirmed by a blood test. But, a blood test may not reveal infection in people who have been receiving antibiotics.

In sepsis, blood pressure drops, resulting in shock. Major organs and systems, including the kidneys, liver, lungs, and central nervous system, stop functioning normally.

A change in mental status and hyperventilation may be the earliest signs of sepsis coming on.

Sepsis is often life-threatening, especially in people with a weakened immune system or with other illness.