Synonyms
Medical: In a broader sense:
- Sepsis
- Septicemia
- Bacteremia
- Sepsis Syndrome
- Septic shock
- SIRS (systemic inflammatory response snydrome)
- Syndrome of systemic inflammatory reaction
Definition and introduction
In the case of blood poisoning (sepsis), pathogens and their products, which have entered the bloodstream through an entry port and have also colonised organs, cause a systemic combat reaction of the entire organism with the uninhibited release of substances that activate the coagulation, defence and inflammation systems. It is life-threatening and can be accompanied by multi-organ failure. The pathogens are usually bacteria.
Blood poisoning (sepsis) is a dangerous and dreaded complication of a variety of diseases. Such reactions can also be triggered by other causes such as burns, trauma or toxins. This is called SIRS (systemic inflammatory response syndrome). This is an umbrella term that refers to an inflammatory reaction that affects the entire organism, can have various causes and is associated with damage to the end organs. Blood poisoning is the most common cause of SIRS and is triggered by pathogens (usually bacteria).
Frequency of blood poisoning
In Germany it is assumed that about 100,000 – 150,000 people fall ill every year, with women seeming to be slightly less affected. The lethality figures vary between 25% and 50% and certainly depend on the type of pathogen, the severity of the disease and the start of therapy. Blood poisoning (sepsis) is often a consequence of previous infections of certain organs.
The most frequent precursor of blood poisoning is pneumonia (44%), followed by urinary tract infections (10%) and infections of the abdominal organs (10%). Finally, infections of wounds or soft tissues (approx. 5%), e.g. after burns, operations or injuries.
Origin of the disease
The body’s defence cells react to blood poisoning with a very strong defence reaction. The pathogens are usually bacteria that enter the body through an entry port. Once they have overcome the local defence system, they enter the bloodstream.
An inflammation is triggered. The bacteria themselves or their decomposition products or toxic substances (toxins) released by them can have an inflammatory effect. Certain defence cells, the scavenger cells (monocytes/macrophages), release certain substances (cytokines) after their activation through contact with the pathogens.
In high doses, these substances can have a direct damaging effect on the tissue and further promote the inflammatory reaction by activating other defence cells (e.g. granulocytes), which in turn release substances that promote inflammation. These substances are cytokines. These are proteins which stimulate certain target cells to grow, develop and multiply.
In the case of blood poisoning, these cytokines produce massive amounts of tissue toxic substances during this strong defence reaction. These toxic substances include free oxygen radicals and nitrogen monoxide (NO). In addition, the cytokines at the target cells also cause the release of certain mediators, i.e. messenger substances that act on the various layers of blood vessels and cells or tissues.
The structure and function of the smallest vessels are altered. This enables them to dilate and the walls to become more permeable. As a result, fluid passes into the surrounding tissue (interstitial oedema).
The coagulation system is also activated. This alters the blood’s ability to clot and leads to the formation of clots. Blood circulation cannot be adequately ensured and the tissue is undersupplied with oxygen, which is known as ischemic-hypoxic cell damage.
But it is not only the smallest blood vessels that are affected. The larger and larger vessels also dilate, especially in peripheral regions, e.g. the arms and legs, which in turn has an effect on blood pressure. In the beginning, the body counteracts this drop in resistance with an accelerated heartbeat (racing heart) and thus increased blood ejection volume in order to maintain blood pressure. After some time, however, when the heart muscle is also attacked, the body can no longer compensate for this and the blood pressure drops. Since the heart muscle is also affected by the undersupply, the tissues can increasingly no longer be supplied until a shock occurs.
All articles in this series:
