Cholecystitis — Surgical Management

• Biliary obstruction and increased intraluminal pressure: When the cystic duct becomes obstructed (usually by a stone, but occasionally by sludge, inspissated bile, or mucus), bile cannot drain from the gallbladder. This leads to progressive increase in intraluminal pressure, which initially may be self-limiting if the obstruction is intermittent (biliary colic), but continued ductal obstruction triggers inflammation. The elevated pressure compromises mucosal blood flow and leads to local ischemia, particularly affecting the dependent (fundal) portion of the gallbladder, which becomes the epicenter of inflammation. This pressure-induced mucosal injury initiates the inflammatory cascade independent of infection in many early cases.

• Chemical inflammation and phospholipase activation: Bile salts become increasingly concentrated as water is reabsorbed from obstructed bile, and these concentrated bile salts directly damage the gallbladder mucosa. Additionally, pancreatic phospholipase A2 may reflux into the cystic duct and gallbladder (particularly in the setting of increased ductal pressure), where it catalyzes the hydrolysis of phosphatidylcholine to lysophosphatidylcholine, a potent proinflammatory lipid mediator. This chemical injury precedes and amplifies the subsequent immune response, explaining why acute cholecystitis can develop and progress without bacterial infection.

• Secondary bacterial infection and immune activation: While the initial inflammation is sterile in approximately 80% of acute cholecystitis cases within the first 24-48 hours, bacteria—predominantly Escherichia coli, Klebsiella pneumoniae, Enterococcus species, and anaerobes (Bacteroides fragilis, Clostridium species)—eventually colonize the inflamed gallbladder via hematogenous spread or transmural migration. Bacterial lipopolysaccharides (LPS) and lipoteichoic acids activate pattern recognition receptors (particularly toll-like receptors 2, 4, and 9) on macrophages, mast cells, and epithelial cells, triggering release of tumor necrosis factor-α (TNF-α), interleukins (particularly IL-1, IL-6, IL-8), and activation of the complement cascade. These mediators increase vascular permeability, promote leukocyte recruitment, and amplify the inflammatory response, leading to transmural inflammation and potential perforation if unchecked.

• Mucosal ulceration and ischemic injury: Progressive inflammation compromises the microvascular circulation within the gallbladder wall, leading to transmural ischemia. The relatively tenuous blood supply of the gallbladder (supplied primarily by the cystic artery, which is an end-artery) makes it particularly vulnerable to ischemic injury. In vulnerable populations—particularly the elderly, diabetics, and immunocompromised patients—this ischemic injury can rapidly progress to full-thickness necrosis and perforation, often occurring within 24-72 hours if surgery is delayed.

• Gallbladder edema and wall thickening: Neutrophilic infiltration and increased vascular permeability lead to accumulation of edema fluid within the submucosa and muscular layers, with wall thickness typically increasing from the normal 1-2 mm to 3-10 mm or greater. This edema, while protective in some contexts (potentially "walling off" a perforation), also indicates severity of inflammation and correlates with increased risk of complications.

• Acalculous cholecystitis—distinct pathophysiology: In 5-10% of acute cholecystitis cases (and up to 50% in critically ill patients with multiple organ failure), no stone is present. Instead, the pathophysiology involves primary gallbladder ischemia (from sepsis-induced hypotension, vasculitis, or thrombosis), viscous bile or sludge causing functional obstruction, or direct toxic insult from medications or critical illness. Ischemic injury in this context rapidly progresses to transmural necrosis and carries substantially higher morbidity and mortality (30-50%) compared to calculous cholecystitis (0.5-2% with appropriate management).

• Choledocholithiasis (stone-impacted cystic duct): Approximately 80-90% of acute cholecystitis cases result from a gallstone becoming lodged in the cystic duct, obstructing bile flow. Cholesterol stones (accounting for ~80% of gallstones) form when there is supersaturation of cholesterol in bile, a state promoted by obesity, rapid weight loss, pregnancy, prolonged fasting, and certain medications (estrogen, fibrates, octreotide). Pigment stones (bilirubin-containing) develop in the setting of chronic hemolysis, cirrhosis, or biliary stasis and carry slightly increased risk for acute cholecystitis due to their association with altered bile composition. Stones larger than 3 cm carry lower risk of cystic duct impaction but higher risk of gallstone ileus if they erode through the gallbladder wall.

• Acalculous cholecystitis: Represents 5-10% of acute presentations in the general population but up to 50% in critically ill hospitalized patients. Risk factors include prolonged NPO status with resultant bile stasis and inspissation, critical illness with sepsis-induced splanchnic hypoperfusion, major surgery or trauma, mechanical ventilation, total parenteral nutrition (TPN), and blood transfusions. Multiple medications (diuretics, vasopressors) may contribute by further compromising splanchnic perfusion. Immunocompromised patients (HIV/AIDS with CD4 <200, organ transplant recipients) frequently develop acalculous cholecystitis from cytomegalovirus (CMV) or cryptosporidial infection of the bile ducts.

• Cystic duct obstruction from sludge or tumors: Biliary sludge (viscous bile containing cholesterol crystals, bilirubin pigment, and mucus) develops with prolonged stasis and can cause functional obstruction of the cystic duct. Tumors rarely cause cholecystitis but can do so through biliary obstruction; hepatocellular carcinoma extending into the confluence of hepatic ducts and pancreatic head cancer with bile duct invasion are important examples. Strictures (from previous surgery, primary sclerosing cholangitis, or trauma) rarely cause acute cholecystitis unless they affect cystic duct drainage.

• Predisposing conditions and demographic risk factors: The classic "4 F's" remain clinically useful: Female (threefold higher incidence), Forty (peak incidence 50-60 years, though gallstones form increasingly at younger ages), Fat (obesity with BMI >30 increases risk 2-3 fold), and Fertile (pregnancy and postpartum period increase risk due to estrogen effects on cholesterol metabolism and progesterone-induced gallbladder dysmotility). Additional risk factors include rapid weight loss (especially after bariatric surgery or prolonged dieting), diabetes (associated with increased incidence and more severe disease), cirrhosis (portal hypertension and bile duct dilation increase stone formation), hemolytic anemias, and cystic fibrosis.

• Right upper quadrant (RUQ) pain—cardinal symptom: The classic presentation begins with visceral pain (dull, poorly localized) from the inflamed gallbladder organ itself, transmitted via visceral afferents in the hepatic plexus accompanying the cystic artery. This pain is often precipitated by meals high in fat (which triggers gallbladder contraction via cholecystokinin) and persists for 6-12 hours, distinguishing it from biliary colic (which typically resolves within 15-60 minutes). As inflammation involves the parietal peritoneum, the pain localizes to the RUQ, becoming sharp and reproducible with movement. In some patients, the pain may be epigastric or referred to the right shoulder or scapula (Kehr's sign—diaphragmatic irritation), but RUQ tenderness is the hallmark.

• Nausea and vomiting: Present in 70-80% of patients, these symptoms result from visceral afferent stimulation and the associated peritoneal inflammation, and may lead to volume depletion and electrolyte abnormalities in protracted cases.

• Fever: Low-grade fever (38-38.5°C) is common in uncomplicated cholecystitis due to inflammatory mediator release; higher fevers (>39°C) or rigors suggest complicated disease with suppurative cholecystitis, perforation, or sepsis.

• Murphy's sign: The single most useful physical exam finding, performed by inspiring against the examiner's hand placed on the RUQ; pain that causes inspiration to stop (positive Murphy's sign) suggests gallbladder inflammation, though false positives can occur with RUQ peritoneal irritation from other causes. Conversely, absent tenderness in a febrile patient makes acute cholecystitis less likely and should prompt consideration of acalculous disease or complications.

• RUQ tenderness and guarding: Localized tenderness to palpation at the junction of the rectus abdominis and costal margin (McBurney's point analog) indicates parietal peritoneal involvement; voluntary guarding (patient's protective contraction) is common, while rigid guarding or rebound tenderness suggests perforation or peritonitis.

• Palpable gallbladder mass: A tender mass may be palpated in the RUQ if the gallbladder is distended and if inflammatory exudate has created a localized collection; this finding, when present, suggests more advanced disease with possible abscess formation.

• Important clinical variants:
• Acalculous cholecystitis in critically ill patients: Often presents insidiously without fever or significant pain, with unexplained metabolic derangement or sepsis being the primary clue. High clinical suspicion is needed as diagnosis is frequently delayed.
• Elderly patients: May present with minimal pain but greater systemic toxicity, sepsis, or hypotension; delayed recognition is common and associated with worse outcomes.
• Diabetic patients: Tend to have more severe disease with higher rates of complications, including perforation, gallbladder necrosis, and sepsis.
• Emphysematous cholecystitis: A rare but severe form caused by gas-forming organisms (typically Clostridium perfringens or E. coli) with pneumatosis of the gallbladder wall; presents with severe pain, sepsis, and carries mortality >30%.

• Clinical history and physical exam: RUQ pain lasting >6 hours (distinguishing from transient biliary colic), especially if precipitated by fatty meal, combined with positive Murphy's sign, establishes pretest probability >90% for acute cholecystitis. However, clinical diagnosis alone is insufficiently sensitive or specific (sensitivity 65-78%, specificity 54-94% depending on series), necessitating objective confirmation.

• Laboratory studies:
• White blood cell (WBC) count: Elevated WBC (>10,000/μL) is present in 60-80% of cases and reflects inflammatory response; higher counts (>15,000/μL) suggest more severe disease or complications. Normal WBC does not exclude cholecystitis.
• Liver function tests (LFTs): Mild elevations in aspartate aminotransferase (AST) and alanine aminotransferase (ALT) (2-3 times upper limit of normal) are common; marked elevation (>5 times normal) suggests associated choledocholithiasis with biliary obstruction or hepatitis. Elevated alkaline phosphatase or total bilirubin (>2 mg/dL) indicates common bile duct obstruction.
• C-reactive protein (CRP) and procalcitonin: Nonspecific markers of inflammation; CRP >5 mg/L supports diagnosis of cholecystitis, and values >10 mg/L correlate with more severe disease. Procalcitonin >0.5 ng/mL suggests bacterial infection or severe inflammation.
• Lipase and amylase: Mild elevations may occur if there is edema at the ampulla of Vater or associated biliary pancreatitis, but marked elevations (>3 times normal) should prompt investigation for acute pancreatitis as primary diagnosis.

• Imaging—Ultrasonography (gold standard for initial diagnosis):
• Murphy's sign on ultrasound: Maximal tenderness elicited by applying the ultrasound probe directly over the gallbladder while visualizing it. Present in 87-95% of acute cholecystitis, compared to positive clinical Murphy's sign in 65-78%, making it highly specific.
• Gallbladder wall thickening: >3 mm (measured perpendicular to the wall in the non-dependent aspect) is abnormal; thickening >5-6 mm suggests severe inflammation or complications. Note that wall thickening from congestive heart failure, hypoalbuminemia, or renal failure can cause false positives.
• Pericholecystic fluid: Anechoic (sonolucent) fluid surrounding the gallbladder indicates inflammatory exudate and suggests more advanced disease; when loculated, indicates abscess formation.
• Gallbladder distension: Anteroposterior diameter >4 cm or longitudinal length >8 cm suggests prolonged obstruction.
• Sonographic or physical tenderness: Both constitute positive findings that increase likelihood of cholecystitis.
• Overall accuracy: Ultrasound sensitivity 88-98%, specificity 80-98% for acute cholecystitis when Murphy's sign is positive on sonography.

• CT imaging: Computed tomography is less sensitive than ultrasound for detecting gallstones but excellent for identifying complications (perforation, abscess, emphysematous cholecystitis, hepatic abscess). CT findings of acute cholecystitis include gallbladder wall thickening, distension, pericholecystic fat stranding, and pericholecystic fluid collection. MDCT (multidetector CT) with multiplanar reconstruction and multivolume datasets provides superior definition of anatomy for preoperative planning in complex cases.

• HIDA scan (hepatobiliary iminodiacetic acid scan): Functional imaging that assesses biliary excretion and cystic duct patency; failure of gallbladder visualization at 4 hours despite normal biliary-to-bowel excretion indicates cystic duct obstruction. Sensitivity 94-98%, specificity 85-90% for acute cholecystitis. Primary indications are suspected acalculous cholecystitis or when ultrasound is inconclusive. Less commonly used now due to longer acquisition time compared to ultrasound and cross-sectional imaging.

• Diagnostic criteria for acute cholecystitis: The Tokyo Guidelines 2018 established diagnostic criteria integrating clinical, laboratory, and imaging findings:
• Inflammatory markers: Elevated WBC, CRP, or both
• Imaging findings: Characteristic findings on ultrasound (positive Murphy's sign, wall thickening, pericholecystic fluid, distension) or CT
• Diagnosis: Definite if one inflammatory marker present plus imaging findings; suspected if imaging findings present without inflammatory markers or inflammatory markers present without imaging confirmation
• Severity assessment: Mild (no organ dysfunction), moderate (associated with systemic inflammatory response), or severe (with organ dysfunction—respiratory, cardiovascular, or renal failure)

• Differential diagnosis: Must exclude acute hepatitis (marked transaminitis, jaundice without RUQ stone), pneumonia with pleurisy (chest imaging, respiratory symptoms), pulmonary embolism (risk factors, D-dimer, CTA), acute myocardial infarction (troponin, ECG), perforated viscus (free air on imaging), pyelonephritis (dysuria, pyuria

Initial stabilisation (all patients)

• Bowel rest and IV crystalloid: vomiting and third-spacing from transmural inflammation produce volume depletion; correct hypovolaemia and electrolytes before induction of anaesthesia.
• Analgesia: NSAIDs (e.g., ketorolac) reduce gallbladder prostaglandin-mediated wall tension and are effective in biliary pain; opioids (e.g., hydromorphone) are added as needed. Concern about morphine-induced sphincter of Oddi spasm is largely theoretical and should not delay analgesia.
• Empiric antibiotics: aimed at enteric gram-negatives and anaerobes per the Tokyo Guidelines 2018 and IDSA/SIS intra-abdominal infection guidance — a third-generation cephalosporin (ceftriaxone) plus metronidazole for community-acquired disease, escalating to a beta-lactam/beta-lactamase inhibitor (piperacillin-tazobactam) or carbapenem for severe, healthcare-associated, or grade III disease. Antibiotics are adjunctive, not definitive; TG18 supports stopping them shortly after cholecystectomy in uncomplicated disease.

Definitive management

• Early laparoscopic cholecystectomy: the standard of care, ideally during the index admission and within roughly 72 hours of symptom onset (Tokyo Guidelines 2018; SAGES; WSES). Early surgery shortens hospital stay without increasing bile duct injury compared with delayed interval surgery.
• Critical view of safety: SAGES Safe Cholecystectomy Program requires clearing the hepatocystic (Calot) triangle of fat and fibrous tissue, separating the lower third of the gallbladder from the cystic plate, and identifying exactly two structures entering the gallbladder before clipping anything.

Escalation and bail-out options

• Subtotal (fenestrating or reconstituting) cholecystectomy or conversion to open: correct response when the critical view cannot be achieved in a severely inflamed or fibrotic hilum.
• Percutaneous cholecystostomy: temporising drainage for Tokyo grade III disease or the prohibitive-risk patient (critically ill, acalculous cholecystitis), with interval cholecystectomy once recovered.
• ERCP with sphincterotomy: for concurrent choledocholithiasis or cholangitis, stratified by ASGE high-risk predictors; otherwise intraoperative cholangiography or laparoscopic common duct exploration.

Contraindicated or wrong

• Nonoperative management alone in gangrenous, emphysematous, or perforated disease.
• Ursodeoxycholic acid or dissolution therapy has no role in acute cholecystitis.
• Deferring surgery in pregnancy: SAGES supports laparoscopic cholecystectomy in any trimester; expectant management increases recurrence and fetal loss.

Complications of the disease

• Gangrenous cholecystitis: end-artery cystic arterial supply plus rising intraluminal pressure produces transmural necrosis; suspect with high fever, marked leukocytosis, and a paradoxically absent Murphy sign from denervation. Most common complication and a surgical emergency.
• Perforation: necrosis progresses to full-thickness breakdown, usually at the fundus. Localized perforation walls off as a pericholecystic abscess; free perforation causes biliary peritonitis with rigidity and shock — emergency laparotomy.
• Emphysematous cholecystitis: gas-forming organisms (Clostridium perfringens, E. coli) in an ischemic wall, classically in the elderly diabetic man; gas in the gallbladder wall or lumen on CT or plain film. Emergency — high mortality, urgent cholecystectomy or drainage.
• Empyema (suppurative cholecystitis): frank pus in an obstructed gallbladder; sepsis physiology with a tense, tender RUQ mass.
• Cholecystoenteric fistula and gallstone ileus: chronic pressure necrosis erodes into the duodenum; Rigler triad — pneumobilia, small bowel obstruction, ectopic gallstone. Obstruction at the duodenum is Bouveret syndrome.
• Mirizzi syndrome: stone impacted in the cystic duct or Hartmann pouch extrinsically compresses the common hepatic duct → obstructive jaundice; raises bile duct injury risk at surgery.
• Ascending cholangitis: Charcot triad; Reynolds pentad with hypotension and altered mentation signals suppurative cholangitis requiring emergent biliary decompression.

Complications of treatment

• Bile duct injury: the feared laparoscopic complication, caused by misidentifying the common bile duct as the cystic duct in a foreshortened, inflamed hilum; presents postoperatively with pain, jaundice, or biloma. Prevented by the critical view of safety.
• Bile leak: from the cystic duct stump or a duct of Luschka; persistent pain and fever days postoperatively, confirmed by HIDA or MRCP, managed with ERCP stenting and drainage.
• Cystic/right hepatic artery hemorrhage, dropped gallstones causing delayed intra-abdominal abscess, retained ductal stones, and postcholecystectomy bile-acid diarrhea round out the recognized morbidity.

• RUQ ultrasound is always the first imaging step: pain >6 hours plus sonographic Murphy sign, wall thickening, and pericholecystic fluid seals the diagnosis. If the ultrasound is equivocal, the single best next step is a HIDA scan — nonvisualisation of the gallbladder confirms cystic duct obstruction.
• Early laparoscopic cholecystectomy on the index admission is the answer for acute calculous cholecystitis (Tokyo Guidelines 2018, SAGES). "Discharge on antibiotics with interval surgery in 6 weeks" is the classic distractor.
• Calot (hepatocystic) triangle: bounded by the cystic duct, the common hepatic duct, and the inferior liver edge; it contains the cystic artery and the lymph node of Lund. An aberrant right hepatic artery running through it is the vessel most often injured.
• Critical view of safety, not the infundibular technique, prevents bile duct injury. When inflammation obliterates the anatomy, the correct move is subtotal cholecystectomy or conversion to open, never blind clipping.
• Percutaneous cholecystostomy is the answer for the septic, ventilated, or otherwise prohibitive-risk patient — including most acalculous cholecystitis in the ICU.
• Gas in the gallbladder wall in a diabetic man = emphysematous cholecystitis: emergent operation, not observation.
• Jaundice plus cholecystitis: think Mirizzi syndrome or choledocholithiasis; use ASGE high-risk predictors (visualized ductal stone, cholangitis, markedly elevated bilirubin with a dilated duct) to decide on preoperative ERCP rather than reflexively ordering it.
• Pregnancy is not a contraindication: SAGES supports laparoscopic cholecystectomy in any trimester; delaying to the postpartum period is the wrong answer.
• Porcelain gallbladder and gallbladder polyps raise carcinoma concern and prompt cholecystectomy — an association examiners like to pair with an incidentally calcified gallbladder on CT.