What is Sepsis?
Sepsis is a composite of symptoms and clinical signs that correspond to infection within a patient. This clinically heterogeneous syndrome may be fatal due to the extensive inflammatory processes and organ dysfunction it can provoke.
The New Definition of Sepsis
In 2016, after a revision by the European Society of Intensive Care Medicine and the Society of Critical Care Medicine, sepsis was redefined as “a life-threatening organ dysfunction caused by a dysregulated host response to infection.”
This new definition of sepsis means that the patient’s body, in response to infection, reacts by causing damage to its own organ structures, and this process can progress to the point where death can be an unfortunate end result.
Along with this up-to-date definition of sepsis, up-to-date criteria for evaluating sepsis were also provided; however, let’s first consider the causes of sepsis.
What is the Aetiology of Sepsis?
Sepsis can be caused by various organisms ranging from viruses to fungi to protozoans; however, bacterial infections are the main offenders. Vincent et al. (2009) concluded in the international EPIC II study that gram-negative bacteria were the principal perpetrators, accounting for 62%, while the gram-positives followed with a frequency of 47%. Of these groups, the principle organisms include:
- Staphylococcus aureus and Pseudomonas at 20%
- Escherichia coli at 16%
Different risk factors may predispose persons to become infected by these organisms.
- Non-Communicable diseases (Diabetes Mellitus, Chronic Kidney Disease)
- Liver disease
- Immunodeficient conditions
- The elderly, children, infants
- Corticosteroid Use
- Prolonged Hospital Stay
- Indwelling catheters
What is the Clinical Presentation of Sepsis?
The presentation of sepsis ranges from acute to insidious. There are cases where the patient may indicate a site of infection to cases where there is none apparent. Symptoms and signs of this syndrome generally include the following:
Another early sign of sepsis includes the presence of leukopenia or leukocytosis.
Along with these parameters, there are also specific signs within each organ system that must also be taken into account when investigating the source of primary infection or exploring the secondary effects of the same.
For example, when examining the respiratory system, listen for adventitious sounds or decreased breath sounds that may point to pneumonia and other chest infections. Respiratory causes of sepsis account for 42% of cases, according to the EPIC II study.
Patients who present with abdominal pain should be evaluated to rule out infection sources in abdominal structures such as the appendix, colon, pancreas, gallbladder. Other sources of infection may include the urinary tract and the prostate gland.
Patients with a history of trauma, wounds, and recent surgeries should be evaluated for any signs of wound infection (e.g., pain, erythema, purulent discharge, weeping wound, abscess formation)
In patients who are already admitted to the hospital and have been given invasive adjuncts, such as a central line, urinary catheters, and hemodialysis access sites, evaluate for inflammatory signs around the insertion site.
Warning Signs of Severe Sepsis
Sepsis progresses through a continuum that begins with a systemic inflammatory response syndrome (SIRS) and ends with multi-organ dysfunction syndrome (MODS), where mortality is almost inevitable. Its severest form is known as Septic Shock, a subcategory of sepsis where there is a great probability of mortality due to severe metabolic and circulatory irregularities.
The New Criteria for Evaluating Sepsis
The Sequential Organ Failure Assessment score, otherwise known as the SOFA score, is the new criteria used to evaluate sepsis. It replaces the SIRS Criteria.
SOFA takes into consideration six parameters that relate to specific organ systems. These systems are aligned with clinical signs and laboratory values, which fit into a numerical score ranging from 0 to 4, where 0 corresponds to normal values, and 4 corresponds to a high level of organ failure. See the image below, adapted from Vincent et al. (1996).
Since this criteria at its base enable physicians to assess the level of dysfunction occurring in the patient’s organ systems, the higher the score given, the more probable there will be an increase in mortality.
Using the SOFA criteria, a score equal to and greater than 2 in the presence of confirmed or suspected infection corresponds to organ dysfunction. It indicates a mortality risk of around 10%.
The abbreviated version of the SOFA score, known as quick SOFA or qSOFA, is helpful for screening patients suspected to have sepsis by quickly evaluating three parameters, mental status, systolic blood pressure, and the respiratory rate.
Laboratory and Imaging
The general laboratory, imaging, and special studies for sepsis can include various tests depending on the suspected source of the infection, for example:
- A Chest X-ray may show signs of pneumonia or any other lung infection.
- CT imaging may reveal abdominal abscesses, perforation of the bowels.
- An ultrasound can rule out pelvic sources of infection, as well as in organs such as the gall bladder.
- Cardiac tests (electrocardiogram and troponins) may reveal suspected causes such as Myocardial Infarction.
- Routine tests such as Complete Blood Count and Chemistry studies provide a baseline analysis for infection screening and organ dysfunction (kidney and liver).
- Procalcitonin is a sepsis biomarker and increases in the presence of systemic bacterial infection.
- Blood, urine, and source cultures should be taken for organism identification and antibiotic sensitivities.
- Certain clinical presentations may necessitate abscess aspiration, lumbar puncture, or paracentesis.
- Arterial blood gas is also a beneficial test for analyzing how septic a patient may be.
It is also important to note that serum lactate has become an important test in diagnosing sepsis, especially in relation to septic shock. (Lee and An, 2016)
The image below provides a summary of test results related to sepsis, as adapted from Mahapatra and Heffner (2020):
Treatment of Sepsis
The foundational aspects of treating sepsis rest upon rapid recognition and rapid remedy.
Schmidt and Mandel (2021) explain that resuscitation must be aggressively instituted in order to reperfuse the organs; just like antibiotic therapy, fluid resuscitation should be implemented within the first hour. It is given at 30 mL/kg and should be finalized by the third hour.
Initial antibiotic therapy should aim to cover both gram-positive and gram-negative organisms, any other considerations must be fully in line with the information found in the patient’s history, and physical examination. Where the source of infection necessitates surgical intervention, this must be pursued additionally.
The patient’s response to the treatments should be continuously monitored for improvements or worsening condition, and appropriate transfers should be pre-empted, for example, if the patient needs to be transferred to the Intensive Care Unit.
- Sepsis is a clinically heterogeneous syndrome, which has a progression that can lead to severe cellular, metabolic, and overall hemodynamic dysfunction.
- If left un-recognized or, if it is not treated aggressively, the patient outcomes may be dim.
- The SOFA score is a criteria that is used in-depth and in a quick overview to assess the level of organ dysfunction in suspected or confirmed sepsis.
- Patients should be consistently monitored while exploring for the possible primary source.
- Sepsis is treated with rapid infusion of intravenous fluids and by using broad-spectrum antibiotics.
References and Further Reading
- Bokhari, A.M. (2019) ‘Bacterial Sepsis Clinical Presentation’ in Medscape [Online] Available at: https://emedicine.medscape.com/article/234587-clinical (Accessed 22nd May, 2021)
- Lee, S. M. and An, W. S. (2016) ‘New clinical criteria for septic shock: serum lactatee level as new emerging vital sign’ Journal of Thoracic Disease. 8(7) pp. 1388-1390 [Online] Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4958885/ (Accessed 23rd May, 2021)
- Mahapatra, S. and Heffner, A.C. (2020) ‘Septic Shock’ StatPearls. [Online] Available at: https://www.ncbi.nlm.nih.gov/books/NBK430939/ (Accessed 23rd May, 2021)
- Marick, P.E. and Taeb, A. M. (2017) ‘SIRS, qSOFA and new sepsis definition’ Journal of Thoracic Disease. 9(4) pp. 943-945 [Online] Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5418298/#r1 (Accessed 22nd May, 2021)
- Puskarich, M.A. and Jones, A.E. (2016) ‘Workplace Assessment’, in Tintinalli, J.E. (ed.) Tintinalli’s Emergency Medicine. 8th Edition. McGraw-Hill Education pp 1021-1029
- Rezaie, S. (2016) ‘Sepsis 3.0’ REBELEM. [Online] Available at: https://rebelem.com/sepsis-3-0/ (Accessed 22nd May, 2021)
- Schmidt, G. A. and Mandel, J.. (2021) ‘Evaluation and management of suspected sepsis and septic shock in adults’ UpToDate [Online] Available at: https://www.uptodate.com/contents/evaluation-and-management-of-suspected-sepsis-and-septic-shock-in-adults (Accessed 23rd May, 2021)
- Singer, M. et al. (2016) ‘The Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3)’ JAMA. 315(6) pp. 801-810 [Online] Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4968574/ (Accessed 22nd May, 2021)
- Vincent, J-L. et al. (1996) ‘The SOFA (Sepsis-related Organ Failure Assessment) score to describe organ dysfunction/failure’ Intensive Care Medicine. 22 pp. 707-710 [Online] Available at: https://www.iccueducation.org.uk/uploads/2/3/1/0/23109338/sofa_score.pdf (Accessed 23rd May, 2021)