Cholecystitis

Acute cholecystitis is inflammation of the gallbladder wall. In the great majority of cases (90-95%), a gallstone impacts in the cystic duct, obstructing outflow and triggering distension, venous congestion, bacterial overgrowth and a secondary inflammatory response — calculous cholecystitis. A distinct minority (roughly 5-10%) occurs without any gallstone at all — acalculous cholecystitis — almost always in critically ill patients (prolonged fasting or parenteral nutrition, mechanical ventilation, major trauma or burns, sepsis) where gallbladder stasis and ischemia, rather than mechanical obstruction, drive the same inflammatory cascade. Acalculous disease carries a higher rate of gangrene and perforation than calculous disease and is easy to miss in a sedated or ventilated patient who cannot report pain.^[1]

Gallstones affect a substantial proportion of adults in North America and Western Europe, the large majority of whom remain asymptomatic for life; acute cholecystitis is the most common serious complication in those who do become symptomatic.^[2] Untreated, the sequence is predictable: obstruction leads to distension, ischemia, and, without intervention, gangrene and perforation. The internationally adopted Tokyo Guidelines (TG18) define explicit diagnostic criteria and a 3-tier severity grade (I mild, II moderate, III severe) that together drive nearly every decision in this chapter, from which imaging to order to whether a patient goes to the operating room today or is stabilized first.^[3]

Definitive treatment is cholecystectomy, and the single biggest change in management over the last decade is timing: early laparoscopic cholecystectomy, performed within the same hospital admission rather than after a course of antibiotics and a planned return in 6-8 weeks, is now the guideline-endorsed standard of care wherever a patient's overall condition and local surgical resources allow it — a position adopted by the World Society of Emergency Surgery's 2020 update, whose panel includes a Canadian co-author (Andrew W. Kirkpatrick, Foothills Medical Centre, Calgary, Alberta).^[2] This chapter also covers the pharmacist-relevant work of choosing and stopping biliary antibiotics correctly, differentiating cholecystitis from the more dangerous entity of ascending cholangitis, and supporting patients through the now much shorter window between diagnosis and surgery.

The classic pattern

Right upper quadrant (RUQ) or epigastric pain, often severe and constant — distinguishing it from the waxing-and-waning pain of simple biliary colic (see Assessment & Diagnosis) — that may radiate to the right scapula or interscapular back. Nausea, vomiting, and anorexia are common, fever is frequent but not universal (especially early), and a history of similar but self-limited episodes after fatty meals is typical: biliary colic that this time "didn't go away."^[3]

Murphy's sign

Ask the patient to take a deep breath while palpating the right subcostal margin; inspiratory arrest from pain as the inflamed gallbladder descends onto the examiner's fingers is a positive Murphy's sign. It is the single most useful individual physical finding for this diagnosis, but — like every other individual history, exam, or basic laboratory finding studied — it is not sensitive or specific enough on its own to rule the diagnosis in or out. A systematic review of the history and physical examination found a positive Murphy's sign carried a positive likelihood ratio of only 2.8 (95% CI 0.8-8.6), and even normal right-upper-quadrant tenderness could not reliably exclude the diagnosis (negative likelihood ratio 0.4, 95% CI 0.2-1.1). Clinical gestalt plus imaging — not any single finding — makes the diagnosis.^[4]

Acalculous cholecystitis looks different

In a critically ill, sedated, or ventilated patient, none of the above may be reportable or elicitable. Suspect acalculous cholecystitis in this population with otherwise-unexplained fever, sepsis, leukocytosis, or abnormal liver enzymes, and image early — this variant progresses to gangrene and perforation more often, and more quickly, than calculous disease.^[1]

• The classic "4 F's" for gallstone disease — Female, Forty (increasing age), Fertile (multiparity/pregnancy), and Fat (obesity) — remains a genuinely useful bedside teaching mnemonic, though gallstones and cholecystitis occur across every age, sex, and body habitus.
• Rapid or substantial weight loss, including after bariatric surgery or very-low-calorie diets, which increases cholesterol saturation of bile and gallbladder stasis.
• Pregnancy — elevated estrogen increases cholesterol secretion into bile, and progesterone reduces gallbladder motility.
• Total parenteral nutrition and prolonged fasting — a specific driver of acalculous cholecystitis through gallbladder stasis when the gallbladder is never stimulated to empty.
• Critical illness generally — mechanical ventilation, major trauma or burns, sepsis, and post-cardiac-surgery states are the classic settings for acalculous cholecystitis.
• Medications that promote biliary sludge or stasis: ceftriaxone (forms a calcium-ceftriaxone precipitate causing reversible "biliary pseudolithiasis," typically after several days of therapy) and octreotide (reduces gallbladder motility and cholecystokinin release with ongoing use).
• Hemolytic conditions (e.g., sickle cell disease, hereditary spherocytosis) producing pigment stones through chronic bilirubin overproduction.
• Diabetes mellitus, cirrhosis, and a family history of gallstone disease.
• Older age broadly increases gallstone prevalence and the risk of a complicated (gangrenous, emphysematous, or perforated) presentation.

Right upper quadrant ultrasound in a 72-year-old man with acute cholecystitis, showing gallstones, gallbladder wall thickening, and fluid between the gallbladder and liver — the classic sonographic triad. (Mikael Häggström, M.D., CC0, Wikimedia Commons)

The Tokyo Guidelines (TG18) diagnostic criteria

• Suspected diagnosis — 1 item from A plus 1 item from B.
• Definite diagnosis — 1 item from A plus 1 item from B plus C (imaging confirmation).

^[3]

Severity grading — this, not just the diagnosis, drives the management plan

^[3]

Distinguishing biliary colic, acute cholecystitis, and choledocholithiasis/ascending cholangitis

Laboratory testing

White cell count is often mildly to moderately elevated with a left shift, and CRP is typically elevated — both feed directly into the TG18 systemic-inflammation criterion and severity grade above.^[3] Liver enzymes and bilirubin are usually normal or only mildly elevated in isolated cholecystitis; a more substantial rise in bilirubin, ALP, or GGT should prompt evaluation for concurrent choledocholithiasis rather than being attributed to cholecystitis alone.

Imaging

^[6] A practical pathway: RUQ ultrasound first in essentially every patient with suspected acute cholecystitis.^[2][3] If ultrasound is equivocal but suspicion remains high, cholescintigraphy is the most accurate confirmatory test.^[6] Add MRCP, CT, or proceed toward ERCP if there is concern for a bile-duct stone (an elevated bilirubin, ALP, or GGT, or a dilated common bile duct on ultrasound) — see Choose Initial Treatment for the cholangitis pathway.

• Confirm the diagnosis and assign a TG18 severity grade efficiently — grade, not just "cholecystitis, yes or no," drives the whole plan.
• Control pain and nausea while keeping the patient NPO pending a surgical or interventional decision.
• Start appropriate empiric antibiotics promptly for anything beyond the mildest, non-toxic presentations, and stop them on schedule once source control is achieved rather than by default.
• Achieve definitive source control — early laparoscopic cholecystectomy for the great majority of patients — rather than defaulting to a prolonged antibiotics-then-interval-surgery approach that current evidence no longer supports for most patients.
• Identify concurrent choledocholithiasis or ascending cholangitis promptly, since it changes the plan to urgent biliary drainage ahead of cholecystectomy.
• Recognize and escalate gangrenous, emphysematous, or perforated disease immediately rather than treating it as routine cholecystitis.
• Select a genuinely safe path — percutaneous cholecystostomy plus antibiotics, with cholecystectomy deferred or never performed — for patients too unwell for surgery, rather than pushing an unsafe operation.
• Set patients up with clear counselling on fat restriction, warning signs, and the plan for surgery, whether same-admission or interval.

Why "early" changed from a debate to a default

The randomized ACDC trial compared immediate surgery (within 24 hours of admission) with delayed surgery (7-45 days later, after initial antibiotics): immediate surgery reduced overall morbidity with no difference in mortality, and shortened both hospital stay and cost.^[8] A Cochrane review pooling multiple randomized trials of early (within 1 week of diagnosis) versus delayed (6-12 weeks later) laparoscopic cholecystectomy found shorter total hospital stay with early surgery and no meaningful difference in bile-duct injury or conversion-to-open rate — evidence that overturned the older default of "cool it down with antibiotics, operate electively months later."^[9]

Antibiotic selection and stewardship

Choose empiric antibiotics targeting enteric gram-negatives — and, where biliary instrumentation or a healthcare-associated source is likely, anaerobes and Enterococcus — based on TG18 grade and any resistance risk factors (recent hospitalization, prior antibiotic exposure, known ESBL colonization).^[10] See Pharmacologic Treatment Options and Drug Tables for specific regimens.

Adequate source control achieved stop antibiotics within about 24 hours after cholecystectomy for mild-to-moderate (Grade I-II) disease with the gallbladder fully removed — this is an explicit TG18 management-bundle recommendation, not a judgment call, and unnecessary continuation adds cost and resistance pressure without benefit.^[11] Incomplete source control, or Grade III disease continue a longer course, commonly 4-7 days and guided by clinical response — see Drug Tables.^[10]

Percutaneous cholecystostomy — for whom, and what happens after

Reserve for patients whose surgical or physiologic risk is judged too high for even early laparoscopic cholecystectomy, and for Grade II/III disease with local inflammation too severe for safe immediate surgery. It achieves source control (drainage) without removing the gallbladder, buying time for acute inflammation and any organ dysfunction to resolve. A Cochrane review found insufficient high-quality evidence to define precisely which high-risk patients benefit most, or whether cholecystostomy improves survival over antibiotics alone — treat it as a bridge, or as a definitive option for a genuinely poor surgical candidate, not as an automatic substitute for surgery in someone who could otherwise tolerate an operation.^[12] Reassess for interval cholecystectomy once the patient has recovered, since the gallstones — and the risk of recurrence — remain unless the gallbladder is eventually removed.

• NPO (nothing by mouth) while a surgical or interventional decision is pending, with IV fluid resuscitation.
• Early laparoscopic cholecystectomy is preferred over open surgery and over delayed/interval surgery for the great majority of patients — shorter stay, faster recovery, and, per current trial evidence, no increase in bile-duct injury or conversion-to-open rate compared with delayed surgery.^[9]
• Percutaneous cholecystostomy (image-guided, under local anesthesia) for patients too unwell for surgery — see Choose Initial Treatment.
• Urgent ERCP for confirmed choledocholithiasis or ascending cholangitis, ahead of cholecystectomy — see Choose Initial Treatment.
• Correct coagulopathy and optimize hemodynamics before any procedure.
• Nasogastric decompression only for significant vomiting or ileus, not routinely.
• For patients ultimately not undergoing cholecystectomy — a poor surgical candidate managed definitively with drainage alone, or awaiting an interval operation — counsel on a low-fat diet to reduce symptomatic biliary colic episodes; this does not treat the underlying gallstone disease itself.

Pregnancy

Acute cholecystitis is the second most common non-obstetric surgical emergency of pregnancy after appendicitis. Ultrasound remains first-line imaging throughout pregnancy given its safety profile. Do not delay indicated surgery for suspected acute cholecystitis on the basis of gestational age alone — laparoscopic cholecystectomy is considered safe in every trimester where expertise is available, and unresolved intra-abdominal inflammation carries its own risks to the pregnancy. For antibiotic selection, beta-lactams (penicillins, cephalosporins, carbapenems) are generally preferred and considered compatible throughout pregnancy; avoid fluoroquinolones and tetracyclines.

Breastfeeding

Cefazolin, ceftriaxone, piperacillin-tazobactam, ertapenem, meropenem, and metronidazole at standard multidose regimens are all considered compatible with breastfeeding; confirm specifics against each drug's own Drug Database entry. Avoid fluoroquinolones (ciprofloxacin) when a suitable alternative exists.

Pediatrics

Acute cholecystitis is uncommon in children and, when it occurs, is disproportionately linked to hemolytic disease (pigment stones, e.g., sickle cell disease, hereditary spherocytosis) or to acalculous disease following a systemic viral or bacterial illness. The same TG18 diagnostic and severity framework applies, adapted with pediatric surgical and imaging expertise and weight-based antibiotic dosing.

Older adults

Presentation is more often atypical and blunted — less pronounced fever and pain than the underlying severity would suggest — and gangrenous, emphysematous, and perforated disease are more common at presentation. Maintain a lower threshold for imaging and for early surgical involvement. Frailty and comorbidity burden, not age alone, should determine the choice between early cholecystectomy and a cholecystostomy-first approach in the Grade III pathway.

Critically ill / ICU patients

This is the population at real risk of acalculous cholecystitis: presentation is frequently limited to unexplained sepsis, and diagnosis relies on a lower threshold for imaging rather than a classic history the patient cannot provide. Gangrene and perforation are more common than in calculous disease, and percutaneous cholecystostomy is frequently the preferred initial step given the high surgical risk typical of this population.^[1]

Renal impairment

Dose-adjust piperacillin-tazobactam, the carbapenems (ertapenem, meropenem), ciprofloxacin, and ketorolac (avoid in significant impairment) for reduced renal function; monitor vancomycin levels or AUC closely. Ceftriaxone and cefazolin typically need little to no adjustment. Consult a renal dosing reference or pharmacist for the specific adjustment.

Hepatic impairment

Reduce the metronidazole dose in severe hepatic impairment given reduced clearance of active metabolites, and use acetaminophen cautiously (lower total daily dose) in significant hepatic impairment. Note that mild transaminase or bilirubin elevation is common in cholecystitis itself and does not necessarily indicate drug-related hepatotoxicity. Most cephalosporins and carbapenems do not require specific hepatic dose adjustment.

After laparoscopic cholecystectomy for uncomplicated (Grade I-II) disease, routine postoperative monitoring (vitals, wound check, tolerance of oral intake) is generally all that is needed, and same-day or next-day discharge is standard. Track the antibiotic stop date explicitly — about 24 hours after surgery with adequate source control — rather than defaulting to a longer "standard" course left over from an earlier era of practice.^[11]

After percutaneous cholecystostomy: monitor drain output, plan a tube cholangiogram before removal, and explicitly schedule reassessment for interval cholecystectomy once the patient has recovered, rather than leaving the drain (or a drain-free but gallbladder-in-situ state) as the default long-term plan.

Watch specifically for new fever, worsening pain, or jaundice in the days after cholecystectomy — these suggest a retained common bile duct stone, a bile leak, or a missed injury, and warrant reimaging rather than an assumption of ordinary post-surgical discomfort (see Treatment Failure / Next Step). Confirm routine histopathology is reviewed on every cholecystectomy specimen — unexpected findings, though uncommon, do occur and change follow-up. Complete medication reconciliation at discharge, including the antibiotic end date and any analgesic taper.

1. Persistent fever, pain, or leukocytosis 48-72 hours into appropriate antibiotics without surgery: reimage for gangrene, abscess, or perforation rather than simply broadening or prolonging the antibiotic course.
2. A Grade II/III patient managed initially with percutaneous cholecystostomy who is not improving: reassess for an undrained collection, a malpositioned or occluded tube, or the need to escalate to surgery.
3. Postoperative fever or bile-stained drain output: evaluate for a bile leak or bile-duct injury (imaging, with ERCP as needed) rather than assuming simple surgical-site infection.
4. New or worsening jaundice at any point: reassess for a retained or previously missed common bile duct stone and arrange MRCP or ERCP.
5. A poor surgical candidate managed with cholecystostomy whose comorbidities later improve: reassess for interval cholecystectomy rather than leaving the tube — or a tube-free, gallbladder-in-situ state — as permanent by default, given the ongoing gallstone and recurrence risk.
6. Recurrent biliary symptoms after cholecystostomy tube removal without interval surgery: offer cholecystectomy rather than repeating drainage indefinitely.

• Treating "gallstones on ultrasound" alone as diagnostic of acute cholecystitis without true local and systemic inflammatory signs — gallstones are common and often entirely asymptomatic.
• Defaulting to "antibiotics now, elective surgery in 6-8 weeks" — current trial evidence supports early, same-admission laparoscopic cholecystectomy for the great majority of patients.
• Continuing antibiotics on a fixed multi-day schedule after adequate source control instead of stopping at about 24 hours per the TG18 management-bundle recommendation.
• Missing ascending cholangitis by treating jaundice, RUQ pain, and fever as simply "a bad cholecystitis" rather than recognizing Charcot's triad and pursuing urgent biliary drainage.
• Failing to consider acalculous cholecystitis in a critically ill patient with unexplained sepsis, simply because no gallstones were mentioned on a prior scan.
• Reflexively avoiding morphine for biliary pain over outdated sphincter-of-Oddi-spasm concerns, while reaching for meperidine instead, which carries a real toxicity risk and is not preferred.
• Missing emphysematous or gangrenous cholecystitis by anchoring on "the patient doesn't look that sick," particularly in a patient with diabetes.
• Choosing percutaneous cholecystostomy reflexively in a patient who could actually tolerate early laparoscopic cholecystectomy, rather than reserving it for genuinely high-risk patients or severe local inflammation.
• Forgetting to schedule interval-cholecystectomy reassessment after cholecystostomy in a patient whose condition later improves.

How to use this table: Doses are adult doses and require patient-specific confirmation (renal/hepatic function, weight, allergy history). Pediatric dosing is weight-based per the current product monograph unless stated. Drug pricing is intentionally omitted. Select any drug name to open its complete Pharmasist Drug Database page.

Empiric Antibiotics — Grade I/II (Mild-to-Moderate) Community-Acquired Disease

Stop within about 24 hours after cholecystectomy once source control is adequate; a full listed course applies only when the gallbladder is not removed promptly.

Empiric Antibiotics — Grade III (Severe) or Healthcare-Associated / High Resistance-Risk Disease

Broader single-agent or combination coverage; continue for a defined course (commonly 4-7 days) guided by clinical response and adequacy of source control.

Beta-Lactam Allergy Alternative

Analgesia and Antiemesis

Scheduled multimodal analgesia (acetaminophen plus an NSAID where appropriate) is preferred over an opioid-first approach; reserve opioids for breakthrough pain.