Sepsis is born out of an infection, but an uncomplicated infection is not sepsis. In other words, sepsis always involves an infection but an infection does not always involve sepsis. Infection is the trigger. Sepsis is a dysregulated, multifaceted response of the body to an infection. Common inciting infections include pneumonia, bloodstream infections (such as from skin contaminants or endocarditis), IV catheter-related infections, abdominal infections, urinary tract infections, and surgical wound infections. Initial symptoms of sepsis are related to the infection including fever, flushing, tachycardia, tachypnea, altered mental status, and hypotension.
Diagnostic Criteria:
There is no one clinical exam finding or test to measure a dysregulated host response. But there are examination findings and lab tests that can serve as indicators that a patient is in sepsis.
SOFA
Organ dysfunction can be categorized by using the Sequential Organ Failure Assessment (SOFA). This is not meant to be a tool for patient management, but to clinically characterize a patient with sepsis. SOFA criteria include assessing respiratory parameters, coagulation tests, liver function tests, mean arterial pressure (MAP), the Glasgow Coma Scale score, kidney function tests, and urine output. Each of these values is given a score from zero to four with zero being the score for parameters within normal limits. An increase in the baseline SOFA score of 2 points or more means that the patient is experiencing worsening organ dysfunction.
There is a quick and easy version of SOFA that does not require any lab tests and can be done at the bedside as a quick diagnostic called Q SOFA which is a 3 component assessment system:
- systolic blood pressure < 100 mm Hg
- respiratory rate > 21
- change in mental status or Glasgow coma score < 15
SIRS
In the past, sepsis had also been diagnosed by using Systemic Inflammatory Response Syndrome (SIRS) criteria. These criteria are still sometimes used, however, SOFA scores were found to be better predictors of sepsis than SIRS criteria. SIRS criteria include:
- tachycardia (HR > 90 bpm)
- tachypnea (RR > 20 breaths/min)
- fever (T > 38°C or T < 36°C)
- leukocytosis (WBC > 12,000), leukopenia (WBC < 4,000) or bandemia (bands ≥ 10%)
Other Important Considerations
Also, remember that while all these evaluations are important and will guide the clinician to utilize necessary life-saving treatments, it is also important to identify the pathogen that instigated the infection so that the underlying infection can be treated appropriately. Pathogens can be bacterial, fungal, or viral. There are patterns and clues in patient characteristics and history that can aid in the recognition and differentiation between pathogens prior to definitive blood testing, thus preventing the overuse of non-specific, broad-spectrum antibiotics.
