What is Bacterial Sepsis (Sepsis)?
Bacterial sepsis is a serious condition that happens when the body’s reaction to an infection damages its own tissues and organs. This condition was first recognized by the ancient Greek physician Hippocrates and has been updated over time. Nowadays, sepsis is understood as a severe organ dysfunction caused by a disordered bodily response to infection.
Historically, sepsis was thought to be a systemic infection spread via the bloodstream. However, as we developed antibiotics and discovered endotoxins, we understood that sepsis is a far more complex condition. Despite these advances, sepsis remains the most common cause of death in ICU units that don’t deal with heart problems.
In order to help medics intervene sooner, an international meeting in 1991 defined terms like “systemic inflammatory response syndrome” (SIRS), “sepsis”, “severe sepsis”, and “septic shock”. They set specific vital signs and blood work to diagnose SIRS. They also characterized sepsis as SIRS caused by an infection, severe sepsis as sepsis associated with organ dysfunction, and defined septic shock as sepsis that causes low blood pressure despite proper fluid resuscitation. Multi-organ dysfunction syndrome (MODS) refers to the high-level failure of several organs at once.
It’s important to remember that not everyone with SIRS has an infection, nor are all infected people septic. Sepsis stands out from infection by causing a drastic body response and damage to organs. Sepsis and its follow-on effects represent a range of clinical severity and can lead to the failure of several interconnected organ systems.
The Surviving Sepsis Campaign (SSC) was started with the goal of quickly identifying and treating patients with sepsis. The first SSC guidelines incorporated a specific protocol, called early goal-directed therapy (EGDT), forcing hospitals to meet quality measures related to sepsis treatment. However, these measures and guidelines have sparked debates, particularly about whether a structured, one-size-fits-all approach to treatment is better than individualized, patient-specific care. The overall benefit of these measures in reducing death rates is still debated among physicians.
What Causes Bacterial Sepsis (Sepsis)?
Sepsis, a critical syndrome, arises from an inflammatory response when our body is invaded by harmful microorganisms. This response balances both pro-inflammatory (disease-fighting) and anti-inflammatory reactions. The nature and intensity of this process are influenced by factors related to the invading pathogens, such as their type, intensity, and behavior, and host factors like environment, genetic makeup, age, existing diseases, and medications.
When harmful microbes are detected, the body’s response intensifies, triggering inflammation that involves activating white blood cells, enhancing immune response, and eventually leading to cell death. Particularly, neutrophils, a type of white blood cell, are activated early in this cycle, consuming a lot of oxygen to generate toxic substances that can kill microbes. These cells also create a strong germ-killing agent using their unique enzyme. The toxic substances are stored and then released to attack the microbes, causing cell death and releasing more toxic substances leading to more inflammation and tissue damage. If not controlled, this process can turn into a vicious cycle.
The immune system controls these pro-inflammatory responses through various mechanisms. It reduces inflammation by affecting the function of immune cells, increasing the number of regulatory cells, and dampening the immune response. Additionally, signals from the brain and specific nerves stimulate the release of chemicals that help to control inflammation. At the cellular level, the process obstructs the activity of inflammation-inducing genes.
The harm caused by inflammation is primarily due to oxidation when the production of harmful substances surpasses the body’s antioxidant defenses. This damage can occur if the body’s antioxidant protection is inadequate. Recent research is focusing on restoring these antioxidant defenses to protect the body from such damage.
Risk Factors and Frequency for Bacterial Sepsis (Sepsis)
Sepsis is a serious condition that affects almost 1.7 million US adults each year, leading to a high rate of illness and death. In the past, before 2000, nearly 50% of those suffering from severe sepsis or septic shock would pass away from the disease. Now, even with advancements in medicine, the death rate still remains high, at around 20% to 25%. In fact, sepsis accounts for 1 in 3 hospital deaths. Considering that sepsis is becoming more prevalent, great emphasis has been placed on early detection and treatment. This has led to the spending of around $23.7 billion in 2013 alone on managing the disease.
- Sepsis affects nearly 1.7 million US adults every year.
- Before 2000, half of the patients with severe sepsis or septic shock died.
- Despite medical advancements, the death rate is still around 20% to 25%.
- Sepsis is responsible for 1 in 3 hospital deaths.
- Its increasing prevalence has led to a focus on early detection and treatment.
- About $23.7 billion was spent in 2013 alone for sepsis management.
Signs and Symptoms of Bacterial Sepsis (Sepsis)
The process of examining a patient who might have sepsis can be quite different depending on the severity of their condition. When considering a patient’s medical history, it is crucial to evaluate any risk factors tied to a higher mortality rate or sepsis occurrence. Such risk factors include conditions like active cancer, diabetes, chronic lung disease, heart failure and kidney or liver disease. Being older than 65 is also a risk factor because as people age, their immune system becomes less responsive. However, being male or female doesn’t affect the chances of dying from sepsis, as research on this point varies.
There could be a higher chance of a patient developing sepsis if they have any of these health conditions, so it is essential to react quicker if possible.
Similarly, understanding a patient’s recent history, such as a hospital stay or exposure to drug-resistant bacteria, can guide treatment. The most common sources of infection in sepsis patients have been found to be pneumonia, abdominal infections, and urinary tract infections. However, the mortality rate isn’t linked to the site of infection or the type of bacteria. Nevertheless, pinpointing a possible infection source in the early stages of patient evaluation is critical.
The physical exam consists of collecting vital signs to assess the patient’s state and look for signs of a systemic infection response. While the SIRS (Systemic Inflammatory Response Syndrome) criteria has been criticized due to its low specificity in sepsis, it’s still useful to monitor abnormalities in vital signs and systemic responses.
Some situations associated with inflammation damage are better categorized according to their organ systems:
- Lungs, which may have Acute Respiratory Distress Syndrome (ARDS)
- Cardiovascular system, which may show hypotension, or septic shock
- Kidneys, which may display Acute Kidney Injury (AKI)
- Brain, which may have septic encephalopathy
- Bone marrow, which may show anemia of critical illness
- Skeletal muscle, which may show critical illness myopathy
- Peripheral nerves, which may have critical illness polyneuropathy
An initial physical exam should be done quickly, focusing on vital signs and searching for any potential infection sources if sepsis is suspected. This could also entail a pelvic exam if needed.
Testing for Bacterial Sepsis (Sepsis)
To better detect sepsis at early stages, multiple clinical scores have been developed to predict which patients are likely to develop sepsis and who might have worse outcomes. The SIRS (Systemic Inflammatory Response Syndrome) criteria, while useful, has been criticized as too broad and not specific enough.
SIRS was designed to identify systemic response using vital signs and lab work as indicators, not necessarily the source of infection. Even when compared to more recent clinical tools like the qSOFA (quick Sepsis-related Organ Failure Assessment) score, SIRS proved to be more sensitive in flagging potential sepsis cases. A challenge with creating a perfect clinical tool for sepsis diagnosis is that there’s no definitive method for diagnosing sepsis.
Sepsis diagnosis still relies on three types of clinical and lab data: general systemic signs, organ dysfunction/failure signs, and microbiological documentation. SIRS criteria take into account the general systemic signs. Organ failure signs can be indicated by changes in platelets, bilirubin, INR (International Normalized Ratio), creatinine, and lactic acid levels, among other markers. Microbiological documentation usually entails blood cultures but can also include urine, respiratory secretions, and potentially cerebrospinal fluid (CSF). However, over one third of sepsis cases show negative blood cultures, further complicating the diagnosis.
In 2001, the Sepsis-2 Criteria defined parameters combining both physical and lab findings related to organ dysfunction. This played a significant role in the Surviving Sepsis Campaign and CMS Core Measure (SEP-1). Indicators of organ dysfunction specified in SEP-1 include a range of blood pressure, breathing, liver, kidney, and clotting function measurements, as well as lactate levels. When evaluating for the possibility of sepsis, these markers of organ dysfunction should be kept in mind.
If sepsis is suspected, typical tests include:
* Full Blood Count (with differentiation)
* Comprehensive Metabolic Profile
* Lactate level (critical if over 2 mmol/L)
* Coagulation level (critical if elevated)
* Chest x-ray and urinalysis (to find possible infection sources)
* Minimum of 2 blood cultures (should be gathered before antibiotics are administered)
Optional tests that may be helpful but aren’t critical include:
* Procalcitonin
* C-Reactive Protein
* Lipase
* Venous Blood Gas
* DIC Panel
* TSH
* Rapid Flu
* Respiratory Virus Panel
Tools like CT head scans, lumbar punctures, MRI scans, or body part specific CT scans may also be used if needed.
Treatment Options for Bacterial Sepsis (Sepsis)
The treatment of sepsis, a severe infection that spreads throughout the body, has improved over time, leading to a lower death rate. However, survival rates could still be better, as approximately 20-25% of people with sepsis still die from the condition. Treating sepsis involves addressing the infection, helping the patient’s immune system, and supporting organs that might not be working well. Initially, doctors diagnose sepsis, take bodily samples to identify the bacteria causing the infection, provide antibiotics, and treat the source of the infection. Controlling the body’s response to the infection and supporting any failing organs are other key parts of treatment.
Managing sepsis usually follows a set of guidelines known as sepsis bundles. There’s a 3-hour bundle and a 6-hour bundle for when sepsis is first diagnosed and a 24-hour bundle for ongoing management.
In the first three hours, medical staff should:
– Collect samples to identify the type of infection,
– Measure blood lactate levels to see how much oxygen is available to cells,
– Deliver broad-spectrum antibiotics which work against a wide range of bacteria,
– Start giving a saline solution to restore blood pressure if it’s too low or if lactate levels are too high.
In the next three hours, they should:
– Use medications to increase blood pressure if it remains low even after giving fluids,
– Check patient’s response to treatment and the need for further fluids if blood pressure is still low or if lactate levels remain high,
– Re-test lactate levels if they were high to begin with.
In the first 24 hours, they should:
– Give steroids if suitable,
– Keep blood sugar levels below 180 mg/dL,
– Ensure appropriate breathing support for those on ventilators,
– Review antibiotic therapy daily to see if it could be stepped down,
– Feed the patient through a tube if necessary,
– Treat the root cause of the infection within 12 hours of detecting it,
– Provide medication to prevent blood clots,
– Give medicine to prevent bleeding in the stomach.
Starting antibiotics quickly is crucial in treating sepsis. Delaying antibiotics can lead to higher death rates. Even though death from sepsis is not tied to the source of the infection or the type of bacteria causing it, taking longer to start appropriate antibiotics can lead to a higher risk of death.
Timing is less important when it comes to collecting samples to identify the infection. Instead, drawing a significant amount of blood in a sterile way from at least two different locations should be emphasized.
The initial fluid resuscitation involves giving 30 ml/kg of saline fluid (crystalloid fluids). However, the correct amount of fluids in the early stages of sepsis and the best type of fluid to use is still debated. If the patient’s blood pressure stays low despite fluid administration, vasopressors may be used. Vasopressors constrict blood vessels to help maintain blood pressure. If there’s an indication of heart malfunction, a medicine called dobutamine may be added to the vasopressor therapy. Regular re-evaluation of the patient’s condition is critical in guiding management.
Sepsis sometimes triggers your body to respond in a way that affects the body’s organs, causing them to malfunction. If this progresses to affecting the lungs severe enough to require mechanical ventilation, a gentle strategy involving low volumes of ventilator support are used. If red blood cells need to be given due to oxygen needs, current guidelines recommend transfusion only when the haemoglobin concentration falls below 7 g/dL unless the patient has heart disease or is losing blood acutely.
Steroids are sometimes used in septic shock, a severe form of sepsis, because they reduce inflammation and help the body respond appropriately to stress. They’re generally given if the patient’s condition isn’t improving with fluids and vasopressors. Hydrocortisone is generally the preferred steroid because it also has mineralocorticoid effects, which helps maintain blood pressure.
Further studies are still ongoing to find other ways of treating and managing sepsis, because even with these protocols in place, the death rate from sepsis remains high.
What else can Bacterial Sepsis (Sepsis) be?
When doctors are evaluating a patient, they also consider other illnesses or conditions that present similar symptoms. Here are a few categories of conditions they look out for:
Endocrine-related Conditions:
- Adrenal insufficiency – A situation where the adrenal glands do not produce enough hormones for the body.
- Thyrotoxicosis – A condition due to an excessive amount of thyroid hormones in the body.
Toxidromes are another possible cause:
- Salicylate toxicity – A dangerous condition resulting from taking too much aspirin or other salicylates.
- Anticholinergic toxicity – A severe reaction to certain medications that block a neurotransmitter in the body.
- Malignant hyperthermia – A disease that causes a fast rise in body temperature and severe muscle contractions when receiving certain types of general anesthesia.
- Neuroleptic malignant syndrome – A rare reaction to certain psychiatric medications, causing high fever, rapid heartbeat, and sometimes sweating.
- Heat stroke – A serious heat-related illness with symptoms of high body temperature and physical distress.
They also look for severe inflammatory states like:
- Major trauma – Serious injury or shock to the body.
- Pancreatitis – Inflammation of the pancreas.
- Anaphylaxis – A severe allergic reaction that can be life threatening.
- Burns – Skin or other tissue damage caused by fire, heat, radiation, or chemicals.
They will also consider types of shock:
- Cardiogenic shock – A condition where the heart suddenly can’t pump enough blood to meet the body’s needs.
- Distributive shock or sepsis – Shock caused by the dilatation of blood vessels, which can happen if you have a serious infection.
- Obstructive shock – Shock caused by a blockage of blood flow in the heart or vessels.
- Hypovolemic shock – Shock resulting from a severe loss of blood, a common occurrence in serious trauma or dehydration.
What to expect with Bacterial Sepsis (Sepsis)
Over the past twenty years, the seriousness and death rates from sepsis – a life-threatening infection response in the body – have dropped noticeably. However, there still remains a significant need for improvement in how we manage the condition. This decrease in deaths from sepsis is, in part, due to better early detection and treatment, as well as a deeper understanding of the disease itself.
Specific tools have been developed that can provide helpful guidelines for treatment and give doctors more information on a patient’s outlook. These include the SIRS or qSOFA criteria. A key focus of treatment strategies has been setting specific goals that will impact a patient’s prognosis. For instance, the buildup of lactic acid in the body during sepsis has been identified as a reliable indicator for predicting acute phase deaths and in-hospital mortality. If lactic acid levels rise above 4 mmol/L, there is a 28.4% chance of death.
However, using this lactic acid level as a guide for treatment hasn’t been shown to directly affect death rates in these patients. But, a reduction in lactic acid levels within 2 hours has been shown to be a standalone predictor of in-hospital deaths. Additionally, implementing a care strategy known as a bundle – which includes administering specific, broad-spectrum antibiotics – has been shown to reduce deaths further compared to prior methods.
Scores such as the qSOFA and SIRS have been used early on in treatment, with higher scores indicating higher rates of in-hospital deaths. For patients who need ICU-level care, the SOFA score has shown to be the strongest predictor of in-hospital deaths.
Most clinical trials and interventions focusing on sepsis tend to concentrate on short-term outcomes, usually looking at deaths within the first 28 days in the hospital. Sepsis still poses a high mortality rate after hospital treatment, with approximately 31% dying in the first year and up to 43% by the second year. Long-term complications of sepsis include weakness due to critical illness, confusion (delirium), and acute lung injury which add to death rates after the initial 28 days.
While we’ve made progress in treating sepsis, resulting in better short-term survival rates, the overall outlook for sepsis patients is still poor, with death rates remaining alarmingly high.
