Acute cholecystitis

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

Acute calculous cholecystitis usually begins with sustained cystic-duct obstruction. Distension, chemical inflammation, ischaemia and secondary bacterial infection can follow. Pain resembles biliary colic initially but persists, with focal right-upper-quadrant tenderness, fever and raised inflammatory markers. Older adults, people with diabetes and immunosuppressed patients may show little fever despite necrosis or systemic illness.

Assess severity and coexisting duct disease at the same time. Jaundice is not required for cholecystitis; when present it may reflect common-duct stones, inflammatory compression, cholangitis or another hepatobiliary lesion. Ultrasound can show stones, wall thickening, distension, pericholecystic fluid and a sonographic Murphy sign. These findings are supportive and must be interpreted against fasting, liver disease, heart failure and analgesia.

NICE advises early laparoscopic cholecystectomy within one week of diagnosis. This admission strategy treats the source and reduces the interval for recurrence. Antibiotics cover suspected infection but do not remove an obstructing stone. A patient who cannot tolerate surgery needs senior multidisciplinary assessment for image-guided drainage, delayed surgery or a goal-consistent non-operative plan, with explicit review of whether their physiology has improved.

Key points

Suspect acute cholecystitis when right-upper-quadrant pain persists and is accompanied by local tenderness, fever or an inflammatory response.
Use liver tests and ultrasound early, but integrate imaging with the clinical picture because no isolated sign is definitive.
Resuscitate dehydration and sepsis while providing analgesia, antiemetic treatment and thromboembolism prevention appropriate to the patient.
When bacterial infection is suspected, use a complete current hospital biliary regimen with renal and allergy adjustment; the medicine card gives a named NHS adult example with a 48–72-hour review and 5–7-day total course.
Offer laparoscopic cholecystectomy within one week of diagnosis when suitable, because delay exposes the patient to recurrent gallstone events.
For people too unwell for early operation, seek specialist source-control planning rather than treating drainage or antibiotics as automatic definitive care.

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

Calculous obstruction

A gallstone impacted in the cystic duct is the usual initiating event, with duration of obstruction influencing inflammation and ischaemia.

Acalculous injury

Critical illness, low flow, fasting and gallbladder stasis can cause inflammation and necrosis without a stone blocking the outlet.

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

1
Distension and inflammation
Entrapped bile and rising pressure injure the mucosa, release inflammatory mediators and produce sustained somatic tenderness.
2
Ischaemic progression
Persistent pressure impairs mural perfusion, increasing the risk of gangrene, empyema and perforation, especially in vulnerable patients.
3
Secondary infection
Enteric organisms may colonise obstructed bile; bacterial sepsis becomes more likely as necrosis, obstruction and systemic illness increase.

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

Sustained local pain

Continuous right-upper-quadrant pain with inspiratory arrest on palpation is more consistent with gallbladder inflammation than a resolved obstructive episode.

Systemic response

Fever, tachycardia, leucocytosis or rising CRP supports acute inflammation; absence of fever does not reassure in frailty or immunosuppression.

Complicated diseaseRed flag

Peritonism, palpable mass, shock or gas in the gallbladder wall suggests gangrene, perforation, empyema or emphysematous infection.

Concomitant duct disease

Jaundice and cholestasis require evaluation for choledocholithiasis, Mirizzi syndrome or cholangitis rather than being assigned to uncomplicated cholecystitis.

Acalculous setting

Critical illness, trauma, burns or prolonged fasting can produce acalculous cholecystitis with subtle abdominal signs and rapid deterioration.

Red flags requiring action

Generalised guarding, shock or free gas suggests perforation and demands immediate surgical reassessment.
New jaundice or sepsis raises concern for common-duct obstruction and cholangitis in addition to gallbladder inflammation.

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
Full blood count and CRPFirst step
Why
Measure the inflammatory response and establish a trajectory.
Interpretation and limitations
Leucocytosis and raised CRP support inflammation but neither localises it. Marked or worsening abnormalities increase concern for complicated disease when coupled with physiology.
02
Liver blood tests
Why
Identify duct obstruction or a hepatic alternative.
Interpretation and limitations
Mild transaminase change can occur in cholecystitis; bilirubin or alkaline phosphatase elevation should prompt focused common-duct assessment.
03
Transabdominal ultrasound
Why
Demonstrate gallstones and supportive inflammatory changes.
Interpretation and limitations
Wall thickening, distension, local fluid and sonographic tenderness strengthen the diagnosis; each has mimics and a negative result may require repeat or alternative imaging.
04
Blood cultures and lactate
Why
Assess severe infection and perfusion when systemic illness is present.
Interpretation and limitations
Obtain cultures before antibiotics when this causes no material delay. Lactate trends response but neither a normal result nor negative cultures excludes local necrosis.
05
CT or alternative biliary imaging
Why
Define perforation, abscess, duct disease or an alternative diagnosis when ultrasound is incomplete.
Interpretation and limitations
Choose the modality for the unresolved question; imaging should not postpone urgent source control in a deteriorating patient with convincing complicated disease.

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

Biliary colic

Transient cystic-duct obstruction causes a self-limited attack without the sustained fever, inflammatory response or local peritonism expected during established cholecystitis.

Acute hepatitis

Hepatic inflammation can cause right-sided discomfort and striking transaminase elevation, with exposure history and serology guiding evaluation.

Lower-lobe pneumonia

Basal pleural irritation may produce upper abdominal pain; respiratory symptoms, oxygenation, chest examination and imaging identify the alternative source.

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

01Worked case: early source controlMove from diagnosis to theatreFirst stepAn adult has eighteen hours of right-upper-quadrant pain, fever, neutrophilia and ultrasound evidence of stones, thickened gallbladder wall and local fluid without duct dilatation.

1Resuscitate, provide analgesia and assess anaesthetic and sepsis risk while obtaining a complete history of anticoagulants, comorbidity and previous attacks.
2Diagnose acute calculous cholecystitis from the concordant clinical, laboratory and ultrasound pattern; lack of jaundice makes common-duct obstruction less likely but does not remove all uncertainty.
3For this adult, start the current hospital biliary regimen after checking allergy and renal function, then offer laparoscopic cholecystectomy within one week of diagnosis after informed consent.
4EscalationVerify improvement and operative readiness with repeat observations, renal function and examination, and record an escalation threshold if physiology worsens before theatre.

02Deteriorating diseaseFind a complicationPain becomes generalised and blood pressure falls despite initial treatment.

1Repeat ABCDE assessment and call senior surgical and anaesthetic help immediately.
2Reconsider perforation, gangrene, cholangitis and another abdominal catastrophe rather than simply increasing analgesia.
3Use urgent imaging only if the patient is stable enough and the result will change source control.
4Move to operative, radiological or critical-care intervention with documented ownership.

03High operative riskPlan a bridge deliberatelySevere comorbidity makes immediate cholecystectomy unsafe.

1Define whether risk is reversible and obtain anaesthetic and specialist surgical assessment.
2Treat infection and organ dysfunction and discuss image-guided gallbladder drainage when source control is required.
3Set a time for reassessment and determine whether interval cholecystectomy remains possible.
4Confirm that a drain is functioning and that clinical response, not placement alone, defines success.

Key medicines and prescribing safety1 treatment · regimens, roles and cautions

Provides empirical biliary antimicrobial cover while early cholecystectomy or drainage controls the gallbladder source. Send aspirated or drained bile for culture and revise the regimen to susceptibilities.

Co-amoxiclav for infected acute cholecystitis: current DBTH adult example

For an adult covered by the Doncaster and Bassetlaw Teaching Hospitals September 2025 protocol, give co-amoxiclav 1.2 g intravenously every 8 hours. Review at 48–72 hours and, if improving and absorbing oral treatment, switch to 625 mg orally every 8 hours; the total intravenous-plus-oral course is 5–7 days according to severity and progress, shortened or narrowed when source control and cultures permit. Under the same DBTH acute cholecystitis/cholangitis protocol, if the patient is older than 65 years AND received co-amoxiclav or a cephalosporin in the preceding 2 weeks, use piperacillin/tazobactam 4 g/0.5 g (4.5 g) by intravenous infusion every 8 hours instead, then de-escalate to an appropriate oral antibiotic from cultures or Infection Team advice; the same 5–7-day total course is governed by severity and progress.

This named local example applies to adults without penicillin hypersensitivity or previous co-amoxiclav-associated jaundice or hepatic dysfunction. Check renal function before dosing: the current 1,000/200 mg intravenous SmPC uses an initial 1,000/200 mg then 500/100 mg every 12 hours when creatinine clearance is 10–30 mL/min, or every 24 hours below 10 mL/min; seek pharmacy advice for oral step-down. Monitor hepatic function and use the hospital allergy pathway or infection-team advice instead of co-amoxiclav after a serious beta-lactam reaction. For piperacillin/tazobactam, the current SmPC specifies infusion over 30 minutes, no renal change above 40 mL/min, 4 g/0.5 g every 8 hours as the maximum at creatinine clearance 20–40 mL/min, and 4 g/0.5 g every 12 hours below 20 mL/min. Avoid it after penicillin hypersensitivity or a severe immediate reaction to another beta-lactam.

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

Gangrene and perforation

Rising intraluminal pressure can compromise gallbladder-wall perfusion, leading to necrosis, local abscess, free bile peritonitis or systemic sepsis.

Empyema

An obstructed gallbladder may fill with infected pus, creating a source that requires prompt drainage or removal.

Bile-duct involvement

Migrating stones or inflammatory compression can produce obstructive jaundice and ascending cholangitis, creating a separate need for duct imaging and drainage.

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

Repeat observations and urine output during resuscitation, especially after each fluid or opioid intervention.
Trend pain distribution, tenderness, temperature, white count and CRP rather than judging response from one measurement.
Review bilirubin and cholestatic enzymes if jaundice develops or recovery stalls.
After operation, monitor wound, respiratory function, oral intake and signs of bile leak or retained duct stones.
If non-operative management is chosen, document the review date, recurrence plan and whether definitive surgery remains intended.

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

Murphy sign is contextual

Analgesia, age and body habitus alter examination; a negative sign cannot overrule convincing systemic and imaging evidence.

Antibiotics are support

They reduce infection burden but cannot reliably resolve continuing obstruction, gangrene or a perforated gallbladder.

Early means diagnosis based

The NICE timing window begins from diagnosis, so avoid serial deferrals that repeatedly reset the clock.

Acalculous disease is different

In critical illness, gallbladder ischaemia and stasis can progress without stones or a classic pain history.

11Common pitfallsFrequent interpretation and management errors.

01
Calling a short self-limited pain episode acute cholecystitis without inflammatory evidence.
02
Treating jaundice as an expected feature and overlooking an infected obstructed common duct.
03
Delaying definitive planning while giving repeated antibiotic courses.
04
Assuming a drain has succeeded without checking physiology, output and repeat imaging when needed.

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