01Principles and purposeThe professional or clinical skill and the decisions it supports.
Peritoneal irritation and sepsis are related but distinct concepts. The peritoneum can be irritated by infected material, gastrointestinal contents, blood or chemical inflammation. Pain on movement and involuntary guarding therefore require an anatomical explanation rather than a reflex assumption that every case has the same infection. Sepsis describes dangerous illness associated with infection; a patient may have it with an initially soft abdomen, a urinary source or a problem outside the abdomen. Keeping the terms separate improves both the differential diagnosis and the choice of intervention.
The key surgical question is whether material must be drained, a leak contained, obstructed infected tissue decompressed or non-viable tissue removed. Antibiotics cannot reliably solve an ongoing anatomical problem on their own. Equally, arranging theatre does not suspend the need to support breathing and circulation. Good assessment connects these tasks and identifies who will decide on definitive treatment. For written and clinical examinations, explain which finding establishes urgency, which establishes a likely source, and what remains uncertain.
Key points
- Peritonism describes signs of peritoneal irritation; it does not identify the organism, organ or need for a particular operation.
- Sepsis assessment requires possible infection plus the degree of illness, with attention to current physiology and trajectory.
- Guarding may be subtle in frail or immunosuppressed people; concerning organ dysfunction can precede dramatic abdominal signs.
- Use the current NG253 pathway for non-pregnant adults, including its 250 mL fluid boluses rather than importing the older generic resuscitation volume.
- Antimicrobial treatment and source control solve different problems; early apparent improvement does not remove a persisting collection or leak.
- Seek joint surgical and critical-care decisions when treatment response is inadequate, without waiting for a complete set of confirmatory results.
02Situations and prioritiesThe context, relevant information and actions that matter most.
Observe movement and cough-related discomfort, then palpate gently to assess whether guarding is localised or widespread. Local tenderness can occur without general contamination; a generally rigid abdomen raises a broader concern. Do not force painful repeated testing when the clinically important information is already evident. Record the distribution because subsequent spread can change the assessment of urgency.
New confusion, mottling, reduced urine production, respiratory distress or circulatory compromise may be more important than fever. Infection should remain possible when temperature is normal or low. In people with recent surgery or impaired immune function, identify the departure from baseline and review recent treatment because the presentation may be less typical.
Consider perforation, complicated diverticular disease, infected obstruction, anastomotic leakage, abscess and wound or soft-tissue infection according to the history. Relate symptoms to prior procedures, drains and devices. A visible wound infection should not distract from a deeper process when the severity of organ dysfunction seems disproportionate to the superficial finding.
Haemorrhage, mesenteric ischaemia, pancreatitis and non-abdominal cardiopulmonary illness can produce severe physiological disturbance. A high lactate or raised inflammatory marker is not exclusive to bacterial infection. Start appropriate urgent care while refining the differential; the purpose of maintaining alternatives is to avoid a wrong definitive pathway, not to postpone treatment until every diagnosis is excluded.
NG253 applies to people aged 16 or over who are not and have not recently been pregnant. Pregnancy and younger age groups have separate sepsis guidance. Suspected neutropenic sepsis also needs its dedicated urgent approach. Establish these modifiers early, because copying an adult general score or treatment sequence into another population may misclassify risk.
03Assessment and interpretationHow to gather information, assess the situation and recognise uncertainty.
Consider the information, its meaning and its limitations before deciding what follows.
- 01
Physiology and structured risk assessment - Why
- Determine the urgency of treatment and the required level of clinical review.
- Interpretation and limitations
- Record the complete observation set and use NEWS2 in the adult hospital population to which it applies. Treat the score as a structured summary rather than a diagnosis. Clinical concern, a concerning single parameter or deterioration can require a higher-risk response. Document when risk was identified so time-sensitive treatments can be assessed accurately.
- 02
Lactate, blood gas and organ-function tests - Why
- Assess metabolic disturbance, perfusion and complications requiring immediate treatment.
- Interpretation and limitations
- A raised lactate increases concern but must be interpreted with haemodynamics, medicines, metabolic factors and the overall presentation. A normal early value cannot exclude bowel ischaemia or another evolving emergency. Compare renal function, blood count and coagulation with baseline where available, and repeat selected tests according to the clinical trajectory.
- 03
Microbiology obtained without treatment delay - Why
- Identify pathogens and support later refinement of antimicrobial treatment.
- Interpretation and limitations
- Take appropriate blood cultures and source samples before antibiotics when this can be achieved promptly. Do not create an avoidable delay to urgently indicated treatment while waiting for difficult sampling or a specialist specimen. Explain the suspected source, prior antibiotics and relevant exposures to help microbiology interpret results.
- 04
Anatomical imaging and source assessment - Why
- Find a treatable lesion and plan surgical or radiological intervention.
- Interpretation and limitations
- Select imaging jointly with the surgical and radiology teams according to the suspected process and physiological stability. For suspected complicated diverticulitis with raised inflammatory markers, NICE recommends contrast CT within 24 hours of admission; that outer timeframe is not a reason to wait in shock or worsening peritonism. Reassess if the report does not explain the clinical severity.
04Worked approachesCases with ordered reasoning, an action and a check of the outcome.
01Worked case: treatment without source closureRecognise a continuing anatomical problemOn the fifth day after bowel surgery, an adult develops abdominal pain, new guarding and confusion. They are considered at high risk from suspected sepsis. Initial treatment improves blood pressure slightly, but pain and respiratory rate continue to worsen.+
- 1Continue immediate physiological reassessment and request urgent senior surgical and critical-care input. The partial blood-pressure response is one observation, not evidence that the underlying problem has resolved.
- 2Obtain source-relevant cultures and urgent blood tests, and give broad-spectrum intravenous antibiotics within one hour of the initial NEWS2 assessment identifying high risk in the emergency department or on ward deterioration, as specified by NG253. Choose the regimen using the source, applicable antimicrobial policy, allergy history, renal function and previous microbiology.
- 3Explicitly raise concern for a postoperative intra-abdominal source, including a possible leak or collection. Discuss the safest urgent imaging and intervention route with the teams who can deliver source control.
- 4The decision is to pursue an urgent source-control assessment alongside ongoing resuscitation, rather than waiting until the next routine ward round because one measurement improved. The appropriate operation or drainage procedure depends on the confirmed anatomy and the patient’s condition.
- 5Verify antibiotic administration, response to each intervention, the senior plan and whether imaging or theatre arrangements are actually progressing. If deterioration continues, repeat escalation and revise the destination and support requirements.
02Current adult sepsis fluidsReassess between small bolusesA non-pregnant adult on the suspected-sepsis pathway needs intravenous fluid resuscitation and has no immediate reason to withhold a fluid challenge.+
- 1Use the NG253 isotonic crystalloid approach: give 250 mL intravenously, ideally over 10–15 minutes, then reassess perfusion, consciousness, blood pressure and respiratory tolerance.
- 2Give further 250 mL boluses only if the reassessment supports them, counting fluids already administered towards 1,000 mL. Watch for overload and obtain earlier senior advice when the clinical picture warrants it.
- 3If improvement remains inadequate after 1,000 mL, obtain advice from a senior clinical decision maker. Continuing automatic boluses can delay recognition that another intervention or circulatory support is required.
03Source-directed escalationLink the referral to the interventionClinical assessment or imaging suggests a focus that may need surgery, drainage or decompression.+
- 1State the suspected source, current organ dysfunction and treatments already delivered when referring. Include relevant anatomy, recent surgery and anticoagulation rather than sending only the label sepsis.
- 2Agree which team will assess the source and how rapidly intervention can occur. NICE calls for necessary source intervention as soon as possible; do not invent one universal hourly deadline for every anatomical process.
- 3Continue reassessment and antimicrobial review after the intervention. Persistent or recurrent deterioration should prompt consideration of incomplete control, another source, complications or a non-infective explanation.
05Relevant medicines and safetySpecific regimens and precautions when the skill involves prescribing.
Isotonic crystalloid for NG253 adult suspected-sepsis resuscitation
Give 250 mL intravenously, ideally over 10–15 minutes; reassess after each bolus. If needed give further 250 mL boluses up to 1,000 mL total including earlier fluids; obtain senior advice if improvement remains inadequate.Stop and reassess for worsening breathlessness or pulmonary congestion. Individualise in cardiac or renal impairment; pregnancy and children require their specific pathways. Do not substitute this regimen for a major-haemorrhage plan or assume the total is a target every patient must receive.
06Feedback, follow-up and evidenceReview outcomes, seek feedback and identify what to improve.
- Reassess clinical perfusion and respiratory status after every fluid bolus; write down both benefit and evidence of harm rather than recording only the cumulative volume.
- Track timing from recognition of high-risk illness to actual antibiotic administration. A drug chart entry alone does not establish that the dose was given.
- Compare abdominal findings with the previous examination and relate new localisation or spreading guarding to the intervention plan.
- After source control, review physiology, organ function, cultures and antimicrobial appropriateness; an intervention is not proof of complete control if the patient continues to worsen.
07Special situationsVariants, exceptions and circumstances that change the usual approach.
Inflammation without bacterial invasion
A physiological inflammatory response can arise from tissue injury or sterile chemical irritation. Avoid presenting a raised white-cell count as proof of bacterial infection. At the same time, uncertainty about mechanism should not reduce urgency when the patient has shock or signs of an abdominal catastrophe.
Why source control matters
An antimicrobial may reach bacteria in the circulation while contaminated material continues to enter the peritoneal cavity. The clinician must therefore ask whether there is a continuing supply of infection or devitalised tissue. That mechanistic question explains why treatment may fail despite apparently appropriate antibiotics.
Subtle findings in vulnerable patients
Reduced muscle mass, immunosuppression, impaired communication and analgesia can make the examination less striking. Use collateral history and serial observations to identify change, while avoiding the assumption that every atypical presentation has a benign explanation.
Different evidence for different decisions
NEWS2 supports a risk response; CT supports an anatomical decision; cultures inform antimicrobial selection. None performs the others’ function. In an assessment, explain what each result contributes and identify the action that can proceed before it returns.
08Common pitfallsFrequent interpretation and management errors.
- 01
Equating peritonism with a single diagnosis can hide haemorrhagic, ischaemic or chemical causes of peritoneal irritation.
- 02
Waiting for fever, leukocytosis or a raised lactate can delay treatment of clinically severe suspected infection.
- 03
Applying a generic 500 mL bolus automatically to the current NG253 suspected-sepsis pathway overlooks its updated smaller-bolus recommendation.
- 04
Treating a brief improvement after antibiotics or fluids as confirmation of source control can leave an untreated anatomical emergency.