Sepsis
Sepsis is life-threatening organ dysfunction caused by a dysregulated host response to infection, identified by an acute rise in SOFA score of 2 points or more in a patient with known or suspected infection. Survival depends on recognizing the pattern early and completing the hour-1 bundle: lactate, blood cultures before antibiotics, broad-spectrum antibiotics such as cefepime 2 g IV every 8 hours, and 30 mL/kg crystalloid for hypotension or a lactate of 4 mmol/L or higher.
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What this article covers
- Overview
Sepsis is organ dysfunction, not just infection: the Sepsis-3 definition is life-threatening organ dysfunction caused by a dysregulated host response to infection, distinguishing it from uncomplicated infection without organ injury.
- Epidemiology
Mortality is markedly elevated: a patient who is septic has a mortality rate 4 or more times greater than for the same underlying condition and comorbidities without sepsis, rising roughly 15% for each additional organ system failure.
- Risk factors
Age older than 65 years, with incidence increasing each subsequent year.
- Pathophysiology
Infection triggers a dysregulated host response: loss of regulation of the body's finely balanced proinflammatory and antiinflammatory mediators is the central abnormality, not simply an exaggerated immune response.
- Clinical features
Known or suspected infection with new organ dysfunction is the core recognition pattern: fever or hypothermia, tachycardia, tachypnea, and a source of infection (pneumonia, urinary tract, abdominal…
- Differential diagnosis
Septic shock: the same infectious process plus vasopressor-requiring hypotension and lactate above 2 mmol/L despite an adequate 30 mL/kg fluid bolus; the discriminator is persistent hypoperfusion…
- Diagnosis
Sepsis is diagnosed by Sepsis-3 criteria: known or suspected infection plus an acute increase in Sequential Organ Failure Assessment (SOFA) score of 2 points or more, with SOFA assigning 0 to 4…
- Management
First, measure serum lactate and draw two sets of blood cultures before antibiotics, but do not delay antibiotics if cultures cannot be drawn immediately; complete both within the first hour.
- Complications
Septic shock, vasopressor-requiring hypotension with lactate above 2 mmol/L despite adequate fluids, carrying 40% or greater in-hospital mortality.
- Prognosis
Mortality scales with the number of organ failures: each additional organ system failure adds approximately 15% mortality, and overall sepsis mortality is at least 4-fold higher than the same illness without sepsis.
- Prevention
Prompt removal of unnecessary indwelling catheters and adherence to central-line bundles (hand hygiene, maximal barrier precautions, chlorhexidine skin antisepsis, avoiding femoral access, daily…
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- Septic shock
Septic shock is the subset of sepsis with hypotension requiring vasopressors to maintain a mean arterial pressure above 65 mm Hg plus a serum lactate above 2 mmol/L despite adequate fluid resuscitation, carrying in-hospital mortality of 40% or higher. Management is a timed sequence: 30 mL/kg crystalloid bolus, blood cultures and broad-spectrum antibiotics within 1 hour, norepinephrine titrated to MAP >=65, and escalation to a second vasopressor and stress-dose hydrocortisone when hypotension persists.
- Community-acquired pneumonia
Community-acquired pneumonia is a lower respiratory tract infection acquired outside the hospital that is diagnosed by a compatible clinical syndrome plus a new infiltrate on chest imaging, risk-stratified with CURB-65 or the Pneumonia Severity Index to guide site of care, and treated with empiric antibiotics chosen by site of care and comorbidity, escalating to cover MRSA or Pseudomonas aeruginosa when risk factors are present.
- Bacteremia
Bacteremia is the presence of viable bacteria in the blood, confirmed by positive blood cultures, that ranges from transient and clinically silent to the trigger for sepsis and septic shock requiring urgent source identification and antimicrobial therapy.
- Acute kidney injury
Acute kidney injury is a sudden rise in serum creatinine or fall in urine output from prerenal, intrinsic, or postrenal causes, defined and staged by KDIGO criteria. Management targets the underlying cause, corrects volume and electrolyte derangements, and escalates to renal replacement therapy for refractory hyperkalemia, acidosis, volume overload, or uremia.
- Acute respiratory distress syndrome (ARDS)
ARDS is acute (within 1 week), bilateral, non-cardiogenic hypoxemic respiratory failure from diffuse alveolar damage, diagnosed by the 2012 Berlin criteria and graded by the Pao2/Fio2 ratio. Management is lung-protective ventilation, PEEP titration, early prone positioning for severe disease, conservative fluid strategy, and treatment of the inciting insult.
- Disseminated intravascular coagulation
Disseminated intravascular coagulation is a secondary, systemic activation of coagulation and fibrinolysis, most often from sepsis, that simultaneously consumes platelets and clotting factors, causing microvascular thrombosis and bleeding. Diagnosis rests on a laboratory constellation, thrombocytopenia, prolonged PT and aPTT, low fibrinogen, and elevated D-dimer, in a predisposing clinical setting, and management centers on treating the underlying trigger while replacing blood components only for active or high-risk bleeding.