Brief overview
- Causes and risk factors: Infection with pathogens such as bacteria, and less commonly viruses or fungi, which cause an immune response.
- Diagnosis: checking various vital signs such as respiratory rate, serum lactate levels, oxygen saturation, inflammation levels by blood tests, for example, as well as classification of brain and consciousness function
- Course of disease and prognosis: If left untreated, sepsis is always severe and often leads to death; with treatment, the course is often favorable.
- Prevention: General hygiene measures in the private environment, comprehensive hospital and clinic hygiene to prevent hospital infections, careful wound treatment, have infectious diseases clarified by a doctor at an early stage, take advantage of vaccinations.
What is blood poisoning or sepsis?
Thus, blood poisoning does not result from the presence of pathogens in the blood, as is often assumed, but from the body’s reaction to these pathogens.
The immune system tries to defend itself against the pathogens, however, this fight harms not only the invaders but also the body itself. Sepsis is a potentially life-threatening condition and requires treatment as quickly and consistently as possible.
The body’s healthy immune system copes effortlessly with such small amounts of pathogens. Only when this is no longer the case and one becomes ill as a result of this fight do doctors speak of blood poisoning.
If the blood pressure is no longer stable at a sufficient level due to the body’s own inflammatory reaction, physicians refer to this as “septic shock”. This final stage of blood poisoning endangers the blood supply to vital organs and often leads to multiple organ failure and even death.
SIRS (Systemic Inflammatory Response Syndrome)
However, these criteria are not specific enough and include other conditions with similar symptoms. This means that it is not always sepsis when the SIRS criteria are met. In addition, they give little indication of the potential mortality of the condition, which is a significant criterion in sepsis.
To learn more about triggers and what happens when the body has a systemic inflammatory response, read the article SIRS.
Septic shock
Learn more about the risks of end-stage sepsis in the article Septic Shock.
Neonatal sepsis
A special case of blood poisoning is the so-called neonatal sepsis. It describes blood poisoning in babies in the first month of life. Two types are distinguished here, depending on how quickly the sepsis occurs after birth.
The sepsis criteria of neonatal sepsis are more difficult to recognize than in adult patients. Neonatal sepsis is feared because of its fulminant course. In babies, sepsis leads to life-threatening illness much more quickly.
Symptoms of blood poisoning
You can read everything important about the typical signs of sepsis in the article Blood poisoning – symptoms.
What are the causes and risk factors for blood poisoning?
At the beginning of sepsis, there is usually a localized infection, the causes of which are often bacteria, sometimes also viruses, fungi (Candida sepsis) or so-called protozoa (unicellular organisms). The immune system launches defensive reactions against the invaders in the form of inflammation: The blood flow to the affected tissue increases, as does the permeability of the blood vessels.
However, the concentrated defenses of the immune system are sometimes not sufficient to limit and eliminate the infection at its point of origin. The pathogens then gain the upper hand: The pathogens and their toxins enter the bloodstream. According to the definition of sepsis, physicians do not yet speak of blood poisoning in this case, but of bacteremia (bacteria in the blood).
Vessels throughout the body dilate, causing a drop in blood pressure. At the same time, signs of inflammation in the blood increase dramatically, while the heart and lungs try to compensate for the lack of return blood flow and its enrichment with oxygen by working harder. As a result, breathing and heart rates increase.
Due to the altered blood flow as well as damage to vessels and tissues by the pathogens and the immune system, the blood clots faster.
In principle, the causes of sepsis include all localized infections such as pneumonia or urinary tract infections. Hospital infections (nosocomial infections) are often the trigger of sepsis. The risk of sepsis is particularly high in:
- Very young (newborns) as well as very old people and pregnant women.
- Wounds or injuries, such as large burns
- Certain treatments and examinations such as catheters in blood vessels, bladder catheters, wound drains
- Addictive disorders, for example alcoholism, drug addiction
- Genetic predisposition to sepsis
Investigations and diagnosis
Therefore, additional criteria are used: The so-called Sequential Organ Failure Assessment (SOFA,Sequential Organ Failure Assessment) is a very complex screening tool well known from intensive care medicine.
A somewhat simplified model is called “quick SOFA” (qSOFA) and includes three important clinical parameters:
- Respiratory rate/breath rate ≥ 20 breaths/min.
- Glasgow Coma Scale (GCS) < 15 (used to assess disorders of consciousness and brain function).
Blood poisoning is suspected when two or more of these items apply to affected individuals.
Physicians review other clinical signs according to the SIRS criteria below, such as:
- Presence of infection, e.g., by microbiological evidence of pathogens in a patient specimen (blood specimen, urine specimen, wound swab) or pneumonia on an x-ray
- Heart rate at or above 90 beats per minute (tachycardia).
- Certain changes in the CBC: leukocyte (white blood cell) count either elevated (≥12,000/µL) or decreased (≤4,000/µL) or ≥ ten percent immature neutrophils (subset of white blood cells)
- Increase in the inflammatory parameters CRP (C-reactive protein) or pro-calcitonin.
- Coagulation disorders, decreasing number of blood platelets (thrombocytes).
- Surgical or hidden causes of sepsis by ultrasonography, computed tomography (CT), or magnetic resonance imaging (MRI)
If organs function only to a limited extent, physicians speak of an infection in terms of severe sepsis. This is true even if the causes of sepsis have not yet been identified. If a critical drop in blood pressure is also present, this is referred to as septic shock.
A prerequisite for the successful treatment of sepsis is the treatment of the underlying disease, i.e. the infection that led to the blood poisoning. This is done either surgically or with medication.
Treatment of sepsis always begins with a search for the source of infection, such as an inflamed appendix, an infected joint prosthesis, or even seemingly trivial things like a vascular access in the arm or a urinary catheter.
Foreign material in the body is also sometimes the seat of the source of infection, for example screws and plates used in bone surgery or, for example, the “coil” (IUD) for contraception.
In what is called cause control, the physician eliminates this starting point of sepsis as quickly as possible. In some sepsis patients, however, the starting point of the infection cannot be located.
If the infection is fungal (Candida sepsis), viral or parasitic, it is treated accordingly. Immunocompromised persons therefore usually receive an antimycotic against possible fungal pathogens in addition to a broad-spectrum antibiotic.
Treatment for severe course
For the best possible therapy, it is necessary to identify the pathogen. Depending on the pathogen, targeted therapy with an antibiotic or antifungal agent is then given.
Additional measures of sepsis treatment in the intensive care unit are:
- Hydration by infusion (saline or crystalloid solution) to stabilize blood pressure and the cardiovascular system and to maintain tissue perfusion.
- If necessary, the replacement of blood cells and plasma by transfusion
- Supporting the function of affected organs, for example by artificial respiration in the case of (impending) lung failure or dialysis, which relieves the kidney of the task of filtering the blood
- The administration of painkillers and sedatives
- If necessary, blood sugar-lowering insulin therapy, since blood sugar levels rise in some patients with sepsis
- The administration of anticoagulant medications to prevent blood clots (thromboses), which can form anywhere in the body during a severe sepsis episode
Newer therapies with artificial antibodies (immunoglobulins) are still under discussion in severe courses. So far, there is a lack of knowledge about which antibodies are most effective in which form of sepsis. Therefore, this treatment is not yet recommended as standard in sepsis.
Course of disease and prognosis
Without treatment, the fight against the blood poisoning pathogens spreads more and more until damage to vessels and organs finally occurs (severe sepsis).
How quickly sepsis progresses depends on the causative pathogen, the patient’s age and the performance of his immune system.
Organ damage often leaves lifelong damage – for example, impaired or failed kidney function that requires lifelong dialysis (blood washing).
In some patients, sepsis cannot be successfully treated and leads to death.
Roughly speaking, the risk of death from sepsis increases by about one percent per hour without adequate treatment. After one day without treatment, the risk is therefore already 24 percent.
In Germany, 26.5 percent of those affected by septic shock die after 30 days from circulatory failure due to blood poisoning.
Risk of secondary damage
After discharge from the hospital, many patients report late effects of sepsis such as nerve damage (polyneuropathies), muscle weakness or post-traumatic stress, and depression (microscopic nerve damage).
This is especially true for people who are hospitalized or in nursing facilities, for immunocompromised patients, and for patients who have just undergone surgery. These patient groups should inform their doctor immediately in the event of fever, chills, shortness of breath and/or dizziness.
Precautionary measures (prevention) are an important topic, especially in hospitals. Hygiene measures, good wound care and consistent protection of immunocompromised patients can prevent blood poisoning in many cases.
The options available to prevent sepsis depend on the specific cause of the sepsis.
Preventing hospital-acquired infections
Often, the cause of sepsis is an infection that occurs during a hospital stay (nosocomial infection).
Prevention at home
It can be difficult to prevent blood poisoning in the home environment. Nevertheless, there are measures that can be taken to reduce the risk of sepsis:
- Observe general hygiene measures, such as washing hands and food.
- Always clean open wounds thoroughly with clean water and protect them from becoming contaminated again – by using a bandage or wound plaster
- Do not scratch insect bites, as this will result in open wounds
- Perform vaccinations according to the recommendations of the Permanent Vaccination Commission at the Robert Koch Institute (STIKO).