AKT · Infections/Sepsis, fever & healthcare-associated

Sepsis & septic shock

Dysregulated host response to infection → life-threatening organ dysfunction

Overview

A dysregulated host response to infection causing life-threatening organ dysfunction. Sepsis = infection + organ dysfunction; septic shock = sepsis with persistent hypotension needing vasopressors and a raised lactate despite fluid resuscitation. The whole game is EARLY recognition (NEWS2/red-flag criteria, qSOFA) and the SEPSIS SIX within the first hour — antibiotics must not wait for a confirmed source. (The full resuscitation algorithm is on acute_care; this is the infection-recognition hub.)

Recognise

Source of infection + systemic features: fever or hypothermia, tachycardia, tachypnoea, confusion/reduced consciousness, hypotension, mottled/cold peripheries, reduced urine output
Risk-stratify with NEWS2 / NICE sepsis red flags; qSOFA (RR ≥22, altered mentation, systolic BP ≤100) flags high risk; lactate reflects hypoperfusion
Septic shock: persisting hypotension needing vasopressors to keep MAP ≥65 + lactate >2 mmol/L despite adequate fluids — high mortality

Red flags

Red-flag sepsis / septic shock → SEPSIS SIX within 1 hour; lactate >2 (and especially >4) signals hypoperfusion
Neutropenic sepsis (recent chemo) → empirical piperacillin-tazobactam within the hour, don't wait for the count (cross-ref haematology); meningococcal sepsis → non-blanching rash

Differentials & how to tell them apart

Non-infective SIRSpancreatitis, major trauma, burns — systemic inflammation without infection

Other shock (cardiogenic/hypovolaemic/anaphylactic)different mechanism — see acute_care; distributive/warm in sepsis

Neutropenic sepsissepsis with neutropenia post-chemo — pip-tazob within 1 h (cross-ref haematology)

Investigations

Within the hour (Sepsis Six): blood cultures (before antibiotics if no delay), lactate, urine output; FBC/CRP/U&Es/LFTs/clotting, VBG; identify the SOURCE (urine, chest, abdomen, skin, lines, CNS) with targeted cultures/imaging; repeat lactate to assess response.

Management

Sepsis Six within 1 hour (cultures+lactate+urine output / oxygen+IV antibiotics+IV fluids) + source control

1Recognise sepsis early (NEWS2/red flags, qSOFA) and deliver the SEPSIS SIX within the first hour: take blood cultures, lactate and urine output; give oxygen, IV broad-spectrum antibiotics and IV fluids. Don't wait for a confirmed source to give antibiotics.Gate: Persisting hypotension/lactate >2 despite fluids = septic shock → vasopressors (noradrenaline) + critical care; and find/control the SOURCE (drain pus, remove the line) — antibiotics can't clear undrained pus.
2De-escalate to targeted antibiotics once cultures return (stewardship), set a review/stop date; neutropenic sepsis → pip-tazobactam within the hour (cross-ref haematology). Full resuscitation algorithm on acute_care.

SEPSIS SIX within 1 hour: Take 3 (blood cultures, lactate, urine output) + Give 3 (oxygen, IV broad-spectrum antibiotics, IV fluids) — the time-critical bundle; antibiotics per local policy + suspected source, do NOT wait for a confirmed source

Source control — drain an abscess/empyema, remove an infected line/catheter, relieve an obstructed infected system — antibiotics alone won't clear undrained pus

Vasopressors (noradrenaline) for fluid-refractory hypotension — septic shock — target MAP ≥65; escalate to critical care; reassess lactate

De-escalate to targeted antibiotics on cultures — antimicrobial stewardship — narrow the spectrum and set a review/stop date

Key points

Infection + organ dysfunction = sepsis → SEPSIS SIX within 1 HOUR (Take 3: cultures/lactate/urine output; Give 3: oxygen/IV antibiotics/IV fluids); antibiotics don't wait for the source. Septic shock = fluid-refractory hypotension + lactate >2 → vasopressors. Source control is essential (drain pus / remove the line). Neutropenic sepsis → pip-tazobactam (haematology).

Monitor & prognosis

Lactate clearance, NEWS2/observations, urine output, organ function; antibiotic de-escalation/stewardship.

Mortality rises with each hour antibiotics are delayed; early bundle delivery + source control are decisive.

Source: NICE NG51 (sepsis); Surviving Sepsis; cross-ref acute_care, haematology (neutropenic sepsis)