Cholangitis and intra-abdominal sepsis

01OverviewDefinition, clinical context and the essential points that orientate the chapter.

Acute cholangitis results when bacterial infection develops in an obstructed biliary system, commonly from a common-bile-duct stone, malignant stricture or blocked stent. Increased ductal pressure promotes bloodstream spread and rapid deterioration.

Intra-abdominal sepsis also includes perforated viscus, postoperative leak, complicated appendicitis or diverticulitis, infected pancreatic or other collection and ischaemic or devitalised bowel.

The decisive management question is whether infected material, obstruction or nonviable tissue remains. Resuscitation and antimicrobials buy time, while endoscopic, percutaneous or operative source control treats the anatomical driver.

Safe care for cholangitis and intra-abdominal sepsis depends on separating physiological instability from diagnostic uncertainty: resuscitation and infection-control actions proceed while targeted samples, imaging and source-control decisions are arranged.

Antimicrobial decisions in cholangitis and intra-abdominal sepsis should document indication, likely source, allergy phenotype, pregnancy possibility, renal and hepatic function, previous microbiology and the planned review or stop point.

Key points

Acute cholangitis is infection behind an obstructed biliary tree; antibiotics cannot reliably sterilise a pressurised system without drainage.
Charcot triad is fever, jaundice and right upper-quadrant pain, but its absence does not exclude cholangitis.
Take blood cultures before antibiotics when this does not delay treatment; bacteraemia is common and guides de-escalation.
Ultrasound is the usual initial biliary imaging test in a stable patient; CT better assesses perforation, abscess and alternative intra-abdominal sources.
Severe cholangitis requires urgent endoscopic or alternative biliary decompression coordinated with resuscitation and critical care.
Empirical antimicrobial choice is local because resistance, prior instrumentation, allergy and organ function materially alter safe coverage.
Perforation, anastomotic leak, devitalised bowel and abscess require prompt surgical or radiological source control rather than prolonged antibiotics alone.
Review antimicrobial therapy at 48 to 72 hours against cultures, procedure findings and adequacy of drainage.

02AetiologyUnderlying causes, associations and risk factors, with why each one matters.

Biliary obstruction

Common-bile-duct stones, malignant strictures, blocked stents and postoperative narrowing impede bile flow and create the dominant anatomical setting for acute cholangitis.

Perforation and leakage

Perforated bowel, anastomotic leak, complicated diverticulitis, appendicitis and infected postoperative collections contaminate the peritoneal cavity with mixed enteric organisms.

Healthcare-associated flora

Repeated procedures, biliary devices, prolonged admission and recent antimicrobials select resistant Enterobacterales, enterococci and occasionally fungi, making previous microbiology particularly valuable.

03PathophysiologyThe causal sequence from the underlying abnormality to symptoms and harm.

1
Pressure-driven bacteraemia
Obstruction raises intraductal pressure, impairs local immune clearance and permits bacteria and inflammatory mediators to enter lymphatics and the bloodstream.
2
Peritoneal inflammatory cascade
Contamination activates a systemic inflammatory response, vasodilatation and endothelial leak, while ongoing perforation or necrosis sustains microbial load despite antibiotics.
3
Sepsis organ injury
Maldistributed perfusion, myocardial depression, microvascular dysfunction and cellular stress produce acute kidney injury, encephalopathy, coagulopathy and respiratory failure.
4
Source-control failure
An undrained abscess, obstructed duct, devitalised bowel or continuing leak maintains bacterial replication and prevents durable physiological recovery.

04Clinical features and red flagsSymptoms, examination findings, patterns of presentation and time-critical warnings.

Biliary inflammatory syndromeRed flag

Fever or rigors, jaundice and right upper-quadrant or epigastric pain support cholangitis, although older or immunocompromised adults may lack the full triad.

Severe cholangitis physiologyRed flag

Hypotension, confusion, hypoxaemia, oliguria, coagulopathy or thrombocytopenia indicates organ dysfunction and demands urgent decompression and critical-care assessment.

Peritoneal inflammationRed flag

Involuntary guarding, rebound, rigidity, absent bowel sounds or pain worsened by movement suggests contamination, perforation or ischaemia.

Recent intervention clueRed flag

ERCP, biliary stent, abdominal surgery, drain manipulation or transplantation changes anatomy, organism probability and the urgency of specialist source control.

Occult presentation

Frailty, corticosteroids and immune suppression can blunt fever and guarding; unexplained delirium, cholestasis or functional decline may be the presenting signal.

Context changes probability

Recent healthcare exposure, antimicrobial use, travel, procedures, devices, pregnancy, immune compromise and previous resistant isolates materially change the likely diagnosis and treatment risk in cholangitis and intra-abdominal sepsis.

Red flags requiring action

Hypotension, rising lactate, confusion or oliguria indicates sepsis-related organ dysfunction.
Generalised guarding, rigidity or free intraperitoneal gas suggests perforation requiring immediate surgical assessment.
Jaundice with fever and right upper-quadrant pain suggests acute cholangitis from biliary obstruction.
Jaundice, sepsis, hypotension and altered consciousness indicates severe cholangitis requiring urgent drainage.
Persistent sepsis despite antimicrobial therapy suggests failed source control, resistant organisms or an alternative diagnosis.

05InvestigationsWhat to request, why it matters and how to interpret it.

Investigation order

Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.

01
Blood cultures before antimicrobialsFirst step
Why
Identify bacteraemia and susceptibility while preserving diagnostic yield.
Interpretation and limitations
Take at least two appropriately filled sets from separate sites if this causes no treatment delay; previous biliary cultures and resistant isolates should shape empirical choice.
02
Full blood count, CRP, renal, liver and coagulation profile
Why
Assess inflammation, cholestasis, organ dysfunction and procedural risk.
Interpretation and limitations
A cholestatic pattern supports obstruction but normal bilirubin does not exclude early cholangitis. Thrombocytopenia, coagulopathy and acute kidney injury indicate severity.
03
Lactate and blood gas
Why
Detect hypoperfusion and metabolic disturbance during sepsis assessment.
Interpretation and limitations
Trend lactate alongside capillary refill, blood pressure, mental state and urine output; an isolated value neither proves nor excludes abdominal infection.
04
Right upper-quadrant ultrasound
Why
Identify gallstones, duct dilatation, gallbladder inflammation and gross biliary obstruction.
Interpretation and limitations
This is the usual initial biliary imaging test in a stable patient, but nondilated ducts or a negative study do not exclude acute obstruction.
05
Contrast-enhanced CT abdomen and pelvis
Why
Locate perforation, abscess, ischaemia, leak or another intra-abdominal source and support intervention planning.
Interpretation and limitations
Use urgently when peritonitis or non-biliary sepsis is suspected; discuss contrast risk but do not defer essential imaging solely because creatinine is abnormal.
06
MRCP, EUS or ERCP
Why
Define and, for ERCP, treat ductal obstruction after initial assessment.
Interpretation and limitations
MRCP and EUS are diagnostic; ERCP enables decompression and sampling. In severe cholangitis, therapeutic drainage should not be delayed for redundant imaging.
07
Host and prescribing assessment
Why
Identify modifiers that alter diagnostic yield, severity and safe prescribing for cholangitis and intra-abdominal sepsis.
Interpretation and limitations
For abdominal sepsis, record allergy reaction, renal and hepatic function, pregnancy possibility, recent antimicrobials, interactions, immune status and previous biliary or deep-fluid cultures before finalising treatment.

06Differential diagnosisRealistic alternatives and the features that help distinguish them.

Acute cholecystitis

Gallbladder inflammation causes right upper-quadrant pain and fever, usually without the obstructive jaundice pattern of cholangitis unless ductal disease coexists.

Acute pancreatitis

Epigastric pain radiating to the back with raised lipase may follow gallstones and can coexist with obstruction or cholangitis.

Hepatitis or drug injury

Hepatocellular liver injury can cause jaundice and systemic symptoms but does not explain ductal dilatation, purulent bile or a drainable abdominal source.

Mesenteric ischaemia

Disproportionate abdominal pain, metabolic acidosis and vascular risk require urgent contrast CT and surgical review because delayed diagnosis causes bowel necrosis.

07ManagementImmediate care, first-line treatment, alternatives and escalation.

01RESUSCITATETreat sepsis while defining sourceFirst stepBiliary or intra-abdominal infection is accompanied by abnormal physiology or organ dysfunction.

1Use ABCDE, measure lactate and glucose, secure intravenous access, monitor urine output and give oxygen and balanced crystalloid according to physiology.
2Obtain blood cultures promptly and begin intravenous antimicrobials within the sepsis pathway, adjusted for allergy, renal function, recent cultures and healthcare exposure.
3Request early senior, surgical or gastroenterology review and involve critical care for persistent hypotension, rising lactate or respiratory compromise.
4Reassess after every intervention and document the suspected anatomical source, planned imaging and latest acceptable time for drainage or operation.

02DRAINDecompress an infected biliary treeAcute cholangitis is probable, particularly with organ dysfunction, ongoing obstruction or failure to improve.

1Arrange urgent therapeutic ERCP with endoscopy and anaesthetic teams while continuing sepsis resuscitation and correcting major coagulopathy where feasible.
2At ERCP obtain bile for culture when possible, decompress the duct and remove a stone or place a stent according to anatomy and stability.
3If ERCP is unavailable or unsuccessful, obtain immediate specialist discussion for percutaneous transhepatic or operative drainage.
4After decompression, review cultures, bilirubin, fever and organ function and shorten or narrow antimicrobials when source control is adequate.

03CONTROLTreat the non-biliary abdominal sourceImaging or examination identifies perforation, abscess, leak, devitalised bowel or another drainable focus.

1Engage the appropriate surgical and interventional-radiology team as soon as the source is suspected, not after a prolonged antibiotic trial.
2Choose operative repair, resection, washout or image-guided drainage according to contamination, anatomy, stability and local expertise.
3Send deep fluid or tissue for aerobic and anaerobic culture during source control and avoid relying on superficial drain swabs.
4Plan nutrition, thromboprophylaxis, analgesia, drain care and antimicrobial duration through multidisciplinary daily review.

04REASSESSReview response and diagnosisSymptoms persist, physiology worsens or expected improvement in cholangitis and intra-abdominal sepsis has not occurred.

1Repeat observations and examination, reconsider the anatomical source and look actively for obstruction, collection, perforation, ischaemia or another diagnosis complicating cholangitis and intra-abdominal sepsis.
2Reconcile blood, bile and deep-fluid susceptibility results with drainage findings, antimicrobial exposure, absorption, renal function and toxicity; narrow, change or stop abdominal sepsis treatment with a documented reason.
3EscalationEscalate to the relevant medical, surgical, microbiology, infection or public-health team when source control, resistant infection, outbreak management or specialist follow-up is required for cholangitis and intra-abdominal sepsis.
4Give abdominal-sepsis safety-net advice covering recurrent rigors, jaundice, increasing pain, vomiting, confusion, reduced urine output and the route for emergency reassessment.

Key medicines and prescribing safety3 treatments · regimens, roles and cautions

Provides broad enteric Gram-negative, streptococcal and anaerobic cover for selected community-acquired infection.

Co-amoxiclav intravenous regimen

Give 1.2 g intravenously every eight hours only when the local intra-abdominal guideline selects it, with renal adjustment as required.

Check immediate penicillin allergy, liver injury history, renal function and local resistance; it may be inadequate after biliary instrumentation or with resistant previous isolates.

Combines enteric Gram-negative coverage with explicit anaerobic activity for selected abdominal sepsis.

Cefuroxime plus metronidazole

Where locally recommended, give cefuroxime 1.5 g intravenously every eight hours plus metronidazole 500 mg intravenously every eight hours.

Clarify beta-lactam allergy, adjust cefuroxime for renal impairment, review metronidazole interactions and alcohol advice, and narrow promptly after cultures and source control.

Adds rapid concentration-dependent Gram-negative activity in selected severe or resistant-risk infection.

Gentamicin initial dose

Give 5 to 7 mg/kg intravenously as an initial once-daily dose when the local sepsis regimen indicates, then use level-guided dosing.

Use the local dosing weight and nomogram; check renal function, previous aminoglycoside exposure, hearing risk and pregnancy, and obtain levels before repeat dosing.

08ComplicationsImportant consequences, why they occur and why they matter clinically.

Septic shock

Uncontrolled infection causes vasoplegia, myocardial dysfunction and capillary leak, progressing to refractory hypotension and multiorgan failure without resuscitation and source control.

Hepatic and biliary abscess

Ascending or portal spread can create focal collections that require image-guided or operative drainage alongside directed antimicrobial therapy.

Perforation and peritonitis

Inflammation, pressure or ischaemia can rupture hollow viscera or gallbladder, producing diffuse contamination and urgent operative need.

Recurrent obstruction

Residual stones, tumour progression or stent blockage can cause recurrent cholangitis, so definitive anatomical planning and device follow-up remain essential.

09Monitoring and follow-upTreatment response, safety checks and longer-term review.

Repeat observations and lactate according to sepsis severity, with continuous monitoring when haemodynamic or respiratory support is required.
Measure urine output and daily renal function because shock, contrast, aminoglycosides and obstruction can each worsen acute kidney injury.
Trend bilirubin, alkaline phosphatase, transaminases and coagulation after biliary decompression; failure to improve can indicate persistent obstruction.
Review fever, pain, abdominal signs and inflammatory markers after source control rather than judging response from CRP alone.
At 48 to 72 hours reconcile blood, bile or deep-fluid cultures with procedural findings and record antimicrobial route, duration and stop date.
At every review of cholangitis and intra-abdominal sepsis, confirm that the working diagnosis still fits the trajectory and that microbiology or imaging has not revealed a source requiring a different intervention.

10Special situationsVariants, exceptions and circumstances that change the usual approach.

Drainage is causal treatment

Antibiotics penetrate poorly into a pressurised obstructed system; clinical improvement may remain transient until bile can drain.

Normal ducts do not reassure

Ultrasound may show no dilatation early or after previous biliary intervention, so strong clinical suspicion still warrants specialist imaging.

Source-control clock matters

The appropriate intervention and urgency depend on physiology and anatomy; organ dysfunction shortens the acceptable delay to drainage or operation.

Deep samples outperform swabs

Bile, aspirated pus and operative tissue better represent the infecting organisms than material collected from an old external drain.

Duration follows control

A longer antibiotic course cannot compensate for an undrained collection, blocked stent, ongoing leak or nonviable tissue.

Document the decision boundary

For cholangitis and intra-abdominal sepsis, record why treatment, observation, admission, isolation or source control was chosen and which finding would trigger a change of plan.

11Common pitfallsFrequent interpretation and management errors.

01
Do not wait for the complete Charcot triad before diagnosing and escalating suspected acute cholangitis.
02
Do not describe ERCP as merely diagnostic when urgent therapeutic decompression is the clinical objective.
03
Do not continue broad empirical therapy without reviewing cultures, biliary instrumentation history and adequacy of source control.
04
Do not overlook dose adjustment, aminoglycoside levels, penicillin allergy phenotype and major antimicrobial interactions during sepsis.
05
Do not dismiss worsening pain or lactate after initial improvement; perforation, ischaemia or failed drainage may have evolved.
06
Do not allow a positive colonisation-prone test, device sample or nonspecific inflammatory marker to outweigh the clinical syndrome when assessing cholangitis and intra-abdominal sepsis.