Sepsis

Sepsis, also known as blood poisoning, is a critical illness caused by an excessive immune response to an infection. It must always be treated in an intensive care unit so that immediate action can be taken in the event of sudden organ failure. If the cause is not infectious but, for example, burns, it is referred to as SIRS (systemic inflammatory response syndrome). In sepsis, on the other hand, an infection can always be proven or at least suspected.

Theoretically, any infection can trigger sepsis. However, the most common causes in descending order are infections in the respiratory tract (especially pneumonia), the abdominal organs, the bloodstream, kidneys and urinary tract, skin/soft tissue and brain infections. Tubes that are inserted into the body by doctors (bladder catheters, vascular catheters) can also be infected. The causative pathogens are predominantly bacteria, but rarely also fungi, viruses or parasites.

The released components of these pathogens come into contact with immune cells during sepsis, triggering an excessive inflammatory reaction.

The strong inflammatory reaction during sepsis causes several critical problems. Mild inflammation is known to cause the affected area to become warm, swollen and reddened. This is due to the dilation of the blood vessels by signaling substances from the immune cells. The benefit of this is that the immune cells can spread better in the tissue where they are needed. In sepsis, this effect occurs unchecked throughout the entire body. The blood vessels are dilated to such an extent that the blood pressure drops sharply. At the same time, water migrates into the tissue (edema) and is therefore absent from the blood, causing the blood pressure to drop further and the risk of developing circulatory shock (septic shock). In addition, immune reactions are generally very strongly linked to blood clotting. However, what is helpful in the case of minor bleeding can become dangerous in the case of sepsis. This is because the blood can clot within the blood vessels, which impairs blood flow to the organs. On the one hand, this can lead to organ failure; on the other hand, important substances for blood clotting are used up, which subsequently increases the tendency to bleed (consumption coagulopathy).

Organ failure manifests itself differently depending on the organs affected. If the heart is affected, it can no longer pump as much blood and the blood supply to the body is further impaired. In the case of lung failure, the transport of oxygen into the blood is impaired and shortness of breath occurs. In the brain, the disease usually manifests itself through impaired consciousness. In kidney failure, urine production fails and waste products can no longer be excreted. In liver failure, the body is no longer able to produce important blood proteins, which can disrupt blood clotting, among other things. The digestive tract can be affected by intestinal paralysis, for example, which causes the stool to accumulate in the body (ileus).

In addition, the symptoms of the triggering underlying disease are also present, such as pain when urinating in the case of a urinary tract infection or a cough in the case of pneumonia.

To detect the bacteria, a blood sample is taken in a nutrient fluid (blood culture). The pathogen can multiply in this within two to three days and it can be tested whether a change in antibiotic therapy is necessary. It can be particularly practical to take several blood samples from different sites. Although this may be unpleasant, it offers the advantage that a false-positive result due to contamination is almost impossible if the same bacteria grow at the same rate in all blood samples.

It is also important to find the source of the infection (focus search). For example, pneumonia can be visualized by X-ray, the abdominal and pelvic organs by ultrasound and the heart by a swallowing ultrasound. It can also be helpful to examine urine and lung secretions as well as blood. The brain is visualized using computer tomography and the cerebrospinal fluid is removed and examined by means of a puncture in the back. In case of doubt, inserted tubes (e.g. "central venous catheter" or "port-a-cath") are also removed and sent for microbiological examination.

The inflammation values in the blood are particularly important (CRP, IL-6, PCT). At several points in time, there is a rising or falling dynamic, which makes it easier to assess the trend. A lack of oxygen in the organs leads to an increase in lactic acid (lactate), which can also be detected in the blood. Of course, there are also many other values that can provide information about coagulation, blood cells and organ systems.

Antibiotic therapy is started immediately after the blood cultures have been taken (bacterial detection in the blood), i.e. before the bacteria are detected. It is particularly important not to lose any time. Antibiotics are selected for this purpose which experience has shown to be the most effective. These can still be changed if another antibiotic is found to be more effective after the bacteria have been detected (after two to three days). The duration of treatment is usually a maximum of seven to ten days.

Antibiotics are not used for fungi and viruses, as they are only effective against bacterial diseases. The treatment of the focus of infection depends on the underlying disease. For example, purulent foci of infection (abscesses) can be removed.

In the case of circulatory shock, it is important to administer fluids in the form of saline solutions via the vein. This can improve the lack of volume in the blood system. Substances related to adrenaline are also used. These increase blood pressure by constricting the blood vessels and can partially improve the pumping function of the heart.

In the event of respiratory distress, oxygen is initially administered via a "nasal cannula" or mask. In the case of severe lung failure, however, a tube must be inserted directly into the lungs (intubation) to support breathing mechanically.

In the case of kidney failure, the kidney function can be replaced with a machine if necessary. The waste products in the blood are filtered out via a membrane.

To prevent blood clots, thrombosis injections are regularly given into the fatty tissue (usually in the abdomen or legs). Thrombosis stockings can also be used.

Nutrition during sepsis is usually provided via a gastric tube after a short break in feeding. A plastic tube is usually inserted via the nose into the stomach.

Around one in four to five patients dies within 30 days of the onset of sepsis. In the case of septic shock, the mortality rate rises to around 30%.

Critical illness polyneuropathy (CIP) can occur after surviving sepsis with a stay in the intensive care unit. This is manifested by sensory disturbances in the hands and feet as well as muscle weakness in the limbs. The symptoms only improve slowly on their own and cannot be alleviated with medication.

Vaccinations are available against some of the causative infections, such as influenza (flu viruses), pneumococcal bacteria and meningococcal bacteria. Early hospitalization or early transfer to an intensive care unit and the immediate start of treatment are important to prevent a fatal outcome.