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Introduction to Bacteremia, Sepsis, and Septic Shock

by Paul M. Maggio, MD, MBA, Carla Carvalho, MD, MPH

Bacteremia, sepsis, severe sepsis, and septic shock are related:

  • Bacteremia: Bacteria are present in the bloodstream. Bacteremia can result from a serious infection or from something as harmless as vigorous toothbrushing. Most often, only a small number of bacteria are present, and they are removed by the body on its own. In such cases, most people have no symptoms. However, occasionally, bacteremia leads to infections, sepsis, or both.

  • Sepsis: Bacteremia or another infection triggers a serious bodywide response ( sepsis), which typically includes fever, weakness, a rapid heart rate, a rapid breathing rate, and an increased number of white blood cells.

  • Severe sepsis: Sepsis plus either the failure of an essential system in the body or inadequate blood flow to parts of the body due to an infection is known as severe sepsis.

  • Septic shock: Sepsis that causes dangerously low blood pressure ( shock) is called septic shock. As a result, internal organs typically receive too little blood, causing them to malfunction. Septic shock is life threatening.