Bacteremia is the presence of bacteria in the bloodstream. It may be of primary origin (direct entry into the bloodstream via needles, contaminated infusions, catheters, etc.) or secondary (from a primary source of infection through hematogenous or lymphatic dissemination). Most of the time the body itself is able to eliminate them without the infection occurring.
Sepsis is a systemic inflammatory reaction, complex and severe, due to an infectious process. It results from a complex interaction between the infecting microorganism and the host’s proinflammatory and pro-coagulant immune response. It can be caused by bacteria, viruses, fungi and protozoa.
Septicemia would be something like sepsis + bacteremia , but this term is not widely used properly. Many professionals use it as a synonym for sepsis. In sepsis besides the intense inflammatory process there is also the multiplication of bacteria in the blood, sometimes with release of toxins, leaving the clinical picture even worse.
Bacteremia, if it develops into an infection, can cause sepsis. Sepsis can be triggered by any infection, be it blood, urinary, pulmonary, intestinal, skin, etc. The local infection can also reach the bloodstream and cause widespread infection.
The host’s response and the characteristics of the infecting organism are the main pathophysiological variables of sepsis. In this way sepsis progresses when the host can not contain the primary infection due to resistance to opsonization, phagocytosis, antibiotics and the presence of superantigens.
Sepsis, Severe Sepsis, and Septic shock are evolutionary stages of infectious disease.