Sepsis
Life-threatening organ dysfunction caused not by infection alone but by a dysregulated host response to it, in which speed of recognition and treatment is the entire determinant of survival.
In a nutshell
Sepsis is organ dysfunction caused by a dysregulated, excessive host inflammatory response to infection, not by the infection itself. Cytokine release causes vasodilation and capillary leak, dropping perfusion pressure and forcing anaerobic metabolism, hence the rise in lactate. Because each hour of delay increases mortality, treatment is a time-critical bundle.
Classic presentation
A patient with a source of infection who develops fever, tachycardia, tachypnoea, confusion and reduced urine output, progressing to hypotension unresponsive to fluids in septic shock.
Key points
- Sepsis is defined by life-threatening organ dysfunction due to a dysregulated host response, not simply by having an infection.
- Lactate is a marker of tissue hypoperfusion from anaerobic metabolism, not of a specific organ, and is used for risk stratification.
- Cultures should be taken before antibiotics wherever this does not delay treatment beyond the one-hour window.
- Empirical antibiotics are chosen broadly to cover the likely source and organism, then narrowed once cultures return.
- Source control (draining an abscess, removing an infected line) is as important as antibiotics and cannot be substituted for by drugs alone.
- The Sepsis Six (oxygen, cultures, antibiotics, fluids, lactate, urine output) must be completed within one hour of recognition.
First-line investigation
Serum lactate and blood cultures, taken alongside clinical assessment, without delaying antibiotics beyond one hour.
First-line management
The Sepsis Six bundle within one hour of recognition: oxygen, blood cultures, IV broad-spectrum antibiotics, IV fluids, lactate measurement and urine output monitoring.
Exam traps
- Waiting for culture results before starting antibiotics is wrong: cultures should not delay empirical treatment.
- A normal blood pressure does not exclude sepsis; a raised lactate or altered mental state can precede hypotension.
- Sepsis in the elderly or immunosuppressed may present atypically, with confusion or falls rather than fever.
- Fluids alone are not enough if hypotension persists: early escalation for vasopressor support is required in septic shock.
Educational content pending clinical review. Not medical advice.