Sepsis is among the most common and most serious conditions seen in acute medicine, and an important area in the Acute Medicine SCE and MRCP. This overview covers the definition, how sepsis is recognised and where infections usually come from.
Definition
Sepsis is life-threatening organ dysfunction caused by a dysregulated host response to infection. Septic shock is a subset in which circulatory and metabolic abnormalities are severe enough to substantially increase mortality. The emphasis on organ dysfunction is what separates sepsis from uncomplicated infection.
Recognition
Sepsis rarely announces itself. Warning signs include:
- new confusion or reduced consciousness;
- a raised respiratory rate;
- low blood pressure or a high heart rate;
- low oxygen saturation;
- reduced urine output;
- mottled skin or a raised lactate.
Older patients, people who are immunosuppressed and those taking beta blockers may show few classic signs, and a normal temperature does not exclude sepsis.
Early warning scores
In UK hospitals, the National Early Warning Score (NEWS2) is used to identify adults who are deteriorating. A rising score should prompt the question of whether infection and sepsis could be the cause, and it determines how urgently a patient is reviewed.
Common sources
- Chest: pneumonia, including aspiration.
- Urinary tract: pyelonephritis and obstructed, infected kidneys.
- Abdomen: cholangitis, perforation and intra-abdominal collections.
- Skin and soft tissue: cellulitis and necrotising infection.
- Devices: intravenous lines and other implanted material.
- Central nervous system: meningitis and encephalitis.
Identifying the source matters because some infections need more than antimicrobials, such as drainage or surgery.
How to revise
Learn the definition and the signs of organ dysfunction first. In exam questions, look for subtle presentations in older patients, a source that has been missed, and the patient whose observations are deteriorating despite apparently minor symptoms.