Introduction

Bacteria commonly enter the bloodstream (a condition called bacteremia or blood poisoning), but usually only a small number of bacteria do so at a time, and no symptoms develop. Most bacteria that enter the bloodstream are rapidly removed by white blood cells (see Section 16, Chapter 183). Sometimes, however, there are too many bacteria to be removed easily, and an infection develops. An infection that is widespread throughout the bloodstream is called sepsis (or septicemia) and causes severe symptoms. Sepsis can lead to a life-threatening condition called septic shock.