Sepsis is an inflammatory response of the body to a severe infection, which can be fatal if it is not treated in time and adequately. Know the symptoms to fight it quickly.

Sepsis is an inflammatory response of the human body that acts as a defense mechanism to a severe infection, usually caused by bacteria. Still, it may also be triggered by other microorganisms such as fungi, viruses, or parasites. This overreaction of the immune system is really serious. It can cause death in approximately one in three cases since it prevents the blood from performing its functions, and small clots can interrupt blood flow to vital organs.

To better understand what it consists of, it is necessary to define some ways in which sepsis manifests itself, which, ordered from least to greatest severity, are:

• Bacteremia: The presence of bacteria in the blood. We speak of viremia, fungemia, or parasitemia to refer to viruses, fungi, and parasites, respectively. Bacteremia is not a manifestation of sepsis, but it is a requirement for it to occur. Without bacteremia, there is no sepsis.
• Systemic inflammatory response syndrome (SIRS): it is a generalized inflammation produced by an infection (pathogenic microorganism) or by other processes ( pancreatitis, trauma, bleeding, etc.) that are recognized by the presence of two or more of the following phenomena:
• Fever (body temperature greater than 38ºC) or hypothermia (temperature less than 36ºC).
• Heart rate greater than 90 beats per minute.
• Respiratory rate is greater than 24 breaths per minute or low amount of carbon dioxide in the blood (this occurs when breathing is faster than usual, so carbon dioxide is eliminated more quickly).
• Leukocytosis (that is, more than 12,000 white cells per microliter of blood), leukopenia (less than 4,000 white cells per microliter of blood), or what is known in medical terms as ‘left deviation’ (that is, presence in the blood of more than 10% of immature white blood cells, when the normal is that this percentage is lower).
• Severe sepsis: it associates, in addition to what is described above, data that indicate a decrease in blood circulation in some regions of the body, such as the presence of low blood pressure or a reduction in the amount of urine expelled. Severe sepsis carries a high risk of mortality.
• Septic shock: severe sepsis with low blood pressure that persists despite the administration of intravenous fluids (which should help to increase it), for which it is necessary to administer intravenous drugs to achieve a rise in blood pressure.

Epidemiology of sepsis

Worldwide, there are around 18 million cases of sepsis each year. The incidence of severe sepsis varies according to the studies and the population studied. Still, it is approximately 2-3 cases per 1,000 inhabitants, and it occurs in two out of every 100 patients admitted to the hospital. It is common in Intensive Care Units, where approximately 40% of patients develop sepsis of greater or lesser severity.

It is, therefore, an increasingly common phenomenon. In fact, in the context of the current coronavirus pandemic, it is estimated that sepsis is the leading cause of death among those infected by COVID-19.

However, mortality has been reduced due to improved care and increasingly powerful antibiotics to treat them. Even so, about 1,500 people die from sepsis every day around the world.

Causes of sepsis

The microorganisms that cause sepsis usually reach the bloodstream from a source of infection (urinary tract, respiratory tract, accumulations of pus, infected tissues). On other occasions, they can come from the patient’s flora (microorganisms that habitually inhabit areas of the body such as the throat or skin ) or be injected into the blood directly from the outside (contaminated blood transfusions, use of syringes in patients drug addicts).

Other times you do not get to know what the route of entry is. Whether or not the microorganism produces sepsis depends on many factors, including, for example, the aggressiveness of the infectious agent, the number of microorganisms that have invaded the host (infected human being), or the more or less weakened state of the system. Immune to it (hence older people, babies, and patients with weak defenses are more likely to suffer from sepsis).

The microorganisms that most frequently cause sepsis are bacteria, with sepsis caused by viruses, fungi, and parasites being less common.

Within bacteria, and although there have been variations over the years, the leading causes of sepsis are the so-called gram-negative bacteria (so-called because they stain in a certain way in the laboratory due to their structure). Gram-positive patients produce sepsis less frequently. The former also causes a more significant number of complications since it is more frequent than septic shock.