Acute cholecystitis is inflammation of the gallbladder, caused by gallstone-associated cystic duct obstruction in 90–95% of cases (calculous) and by gallbladder-emptying dysfunction without stones in 5–10% (acalculous, typically in critically ill patients). [1] It affects approximately 200,000 people in the US annually, and the definitive treatment is early laparoscopic cholecystectomy, ideally within 72 hours of diagnosis. [1-2]
1. History
- Pain characterization: Acute onset, constant, intense RUQ or epigastric pain lasting >6 hours (distinguishes from biliary colic, which resolves within 5 hours) [3]
- Timing/triggers: Often postprandial, especially after fatty meals; may awaken patient from sleep
- Associated symptoms: Nausea, vomiting, anorexia, fever
- Progression: Ask about prior biliary colic episodes, frequency, and whether pain pattern has changed (longer duration, more severe)
- Important negatives: Absence of jaundice (suggests uncomplicated cholecystitis vs. choledocholithiasis/cholangitis), absence of dark urine/clay-colored stools, no prior biliary surgery
2. Alarm Features
- Charcot's triad (RUQ pain, fever, jaundice) → suggests ascending cholangitis
- Reynolds' pentad (Charcot's triad + altered mental status + hypotension) → septic cholangitis, life-threatening
- Peritoneal signs (rigidity, rebound, guarding) → gangrenous or perforated cholecystitis
- High fever (>39°C), tachycardia, hypotension → sepsis, complicated cholecystitis
- Palpable RUQ mass → gallbladder empyema or phlegmon
- Acalculous cholecystitis should be suspected in ICU patients, post-surgical patients, or immunocompromised patients with unexplained sepsis [1]
3. Medications
- Medication contributors to gallstone formation:
- GLP-1 receptor agonists (RR 1.27), DPP-4 inhibitors (OR 1.22) [3]
- Estrogen-based therapy/oral contraceptives [3-4]
- Ceftriaxone (biliary sludge), octreotide, fibrates, TPN
- Acute treatment:
- NSAIDs (ketorolac, diclofenac) — safe and effective for pain in cholecystitis and biliary colic [3]
- Opioids — for refractory pain; morphine historically avoided due to theoretical sphincter of Oddi spasm, though clinical significance is debated
- Antibiotics — see Treatment Plan below
- Contraindicated/caution: Avoid anticholinergics (worsen gallbladder stasis)
4. Diet
- Acute management: NPO status upon admission in anticipation of surgery [2]
- Dietary triggers: High-fat, fried, or greasy meals classically precipitate biliary colic/cholecystitis episodes
- Risk factors for gallstone formation: High-calorie diets, refined carbohydrates, high fructose intake, low fiber [4-5]
- Protective factors: High fiber, monounsaturated fats (olive oil), omega-3 fatty acids, moderate coffee consumption, moderate alcohol, vitamin C [5]
- Post-cholecystectomy: Low-fat diet initially; most patients tolerate a normal diet within weeks
5. Review of Systems
- GI: Nausea, vomiting, anorexia, bloating, food intolerance (especially fatty foods), change in stool color
- Constitutional: Fever, chills, rigors, malaise
- Genitourinary: Dysuria, hematuria (to rule out nephrolithiasis)
- Cardiopulmonary: Chest pain, dyspnea (cholecystitis can mimic ACS via cholecystocardiac syndrome) [6-7]
- Skin: Jaundice, pruritus (suggests biliary obstruction)
6. Collateral History and Family History
- Prior episodes of biliary colic or known gallstones
- Family history of gallstone disease (genetic component accounts for ~25% of total risk; ABCG8 mutations) [8]
- Pregnancy status in women of childbearing age
- Recent hospitalization, ICU stay, TPN use (risk for acalculous cholecystitis)
- Social history: Rapid weight loss, bariatric surgery history, alcohol use
7. Risk Factors
8. Differential Diagnosis
- Biliary colic — Pain resolves within 5 hours, no fever/leukocytosis, normal US wall [3]
- Choledocholithiasis — Elevated bilirubin, ALP, GGT (OR 3.0); dilated CBD on imaging [3]
- Ascending cholangitis — Charcot's triad; requires urgent ERCP
- Gallstone pancreatitis — Elevated lipase >3× ULN; epigastric pain radiating to back
- Peptic ulcer disease/perforation — Epigastric pain, free air on imaging
- Acute hepatitis — Markedly elevated transaminases (>1000), diffuse liver tenderness
- Right lower lobe pneumonia — Referred RUQ pain; CXR diagnostic [9]
- Appendicitis (retrocecal) — Migrating periumbilical pain, McBurney's point tenderness
- Acute coronary syndrome — ECG changes, troponin elevation; cholecystitis can mimic ACS [6-7]
- Fitz-Hugh-Curtis syndrome — RUQ pain with PID; consider in young women
- Renal colic — Flank pain, hematuria, colicky character
Over one-third of patients initially suspected of having acute cholecystitis have RUQ pain from other causes. [10]
9. Past Medical History
- Prior biliary colic episodes or known cholelithiasis
- Previous cholecystectomy (postcholecystectomy syndrome, retained stones)
- Prior abdominal surgeries (adhesions, altered anatomy)
- Bariatric surgery (especially RYGB — altered biliary access for ERCP) [11]
- Chronic hemolytic conditions (sickle cell, hereditary spherocytosis)
- Cirrhosis (increases surgical risk significantly)
- Diabetes, immunosuppression (atypical presentations, higher complication rates)
10. Physical Exam
- Vital signs: Fever (31–62% sensitivity), tachycardia, hypotension (suggests sepsis) [12]
- Murphy's sign — Inspiratory arrest during RUQ palpation; most specific exam finding (LR+ 11.5–21.3, specificity 96%) [3][12]
- RUQ tenderness — Present in most cases but nonspecific
- Palpable gallbladder — Suggests empyema, hydrops, or Courvoisier sign (malignancy)
- Peritoneal signs — Rebound, guarding → complicated cholecystitis (gangrenous, perforated)
- Jaundice — Low sensitivity (11–14%) but high specificity (86–99%); suggests CBD stone [12]
- Overall clinical gestalt has the highest diagnostic accuracy (LR+ 25–30) [3]
- Caveat: Elderly, immunocompromised, and obese patients often have subtle or atypical presentations [9]
11. Lab Studies
12. Imaging
- First-line: RUQ ultrasound — Sensitivity ~81%, specificity ~83% for acute cholecystitis [1][15]
- Key findings: Gallstones, gallbladder wall thickening (≥5 mm), pericholecystic fluid, sonographic Murphy's sign, gallbladder distension
- Positive predictive value of stones + sonographic Murphy's sign = 92%; stones + wall thickening = 95% [14]
- Gold standard: HIDA scan (hepatobiliary scintigraphy) — LR+ 10.1, LR− 0.1; sensitivity 80–90% [3][14]
- Use when US is negative/equivocal but clinical suspicion remains high
- Non-filling of gallbladder at 60 minutes = cystic duct obstruction
- Limitation: Takes several hours, does not identify extrabiliary pathology
- CT abdomen — Less accurate than US for cholecystitis (LR+ 2.3) but useful for complications (gangrenous cholecystitis, perforation, abscess) and undifferentiated abdominal pain [3][15]
- MRI/MRCP — Comparable accuracy to US; useful for choledocholithiasis evaluation; limited availability in urgent settings [15]
- Imaging unnecessary when: Classic presentation with positive US findings and concordant clinical picture
13. Special Tests
- Tokyo Guidelines 2018 (TG18) Severity Grading: [16-17]
- Grade I (Mild): Does not meet Grade II or III criteria
- Grade II (Moderate): WBC >18,000, palpable RUQ mass, symptom duration >72 hours, marked local inflammation (gangrenous, pericholecystic abscess, hepatic abscess, biliary peritonitis)
- Grade III (Severe): Organ dysfunction (cardiovascular, neurological, respiratory, renal, hepatic, hematologic)
- Bedside Sonographic Acute Cholecystitis (SAC) Score — Combines 3 clinical + 2 POCUS findings; score <2 rules out (sensitivity 100%), score ≥7 rules in (specificity 95.7%) [18]
- Point-of-care ultrasound (POCUS) — High sensitivity (86.6%) but low specificity (17.1%) as standalone; must integrate with clinical and lab data [19]
14. ECG
Acute cholecystitis can produce ECG changes that mimic acute coronary syndrome via the cholecystocardiac syndrome (viscerocardiac reflex through shared T4–T9 spinal innervation): [6-7]
- T-wave inversions (especially anterior leads, mimicking Wellens' syndrome) [7]
- ST-segment elevation or depression [20]
- Arrhythmias: Sinus bradycardia, AV block (Cope sign), atrial fibrillation [6][21]
- Troponin may be mildly elevated due to demand ischemia
- ECG changes typically resolve within 24–48 hours after biliary decompression [6]
- Pearl: Obtain ECG in all patients >40 years or with cardiac risk factors presenting with epigastric/RUQ pain to differentiate from ACS; if ECG changes are present, consider both diagnoses simultaneously [22]
15. Assessment
Acute cholecystitis is a clinical diagnosis supported by imaging, requiring a combination of local signs (RUQ pain/tenderness, Murphy's sign), systemic signs (fever, leukocytosis, elevated CRP), and imaging findings (US evidence of gallbladder inflammation). [13][15] No single finding can establish or exclude the diagnosis. [13]
- Typical presentation: Postprandial RUQ pain >6 hours, fever, nausea, positive Murphy's sign, US showing stones with wall thickening
- Atypical presentations: Elderly (afebrile, vague abdominal pain), diabetics (painless), ICU patients (acalculous), pregnant women
- Complications: Gangrenous cholecystitis (most common complication), gallbladder perforation, pericholecystic abscess, cholecystoenteric fistula, gallstone ileus, Mirizzi syndrome, sepsis
16. Treatment Plan
Initial stabilization
- NPO, IV fluid resuscitation, electrolyte correction
- Analgesia: Ketorolac 15–30 mg IV or diclofenac as first-line; opioids for refractory pain [3]
- Antiemetics as needed
Antibiotic therapy: [13-15][23]
- Uncomplicated cholecystitis: Post-operative antibiotics are not routinely needed if adequate source control achieved by cholecystectomy [13]
- Complicated cholecystitis: 4-day postoperative antibiotic course recommended [15]
Definitive treatment
- Early laparoscopic cholecystectomy (ELC) — Within 72 hours of diagnosis (WSES: within 7 days of admission / 10 days of symptom onset) [1][13][15]
- Pregnancy: ELC recommended during all trimesters (maternal-fetal complications: 1.6% early vs. 18.4% delayed) [1]
- Elderly (>65): Cholecystectomy associated with lower 2-year mortality (15.2%) vs. nonoperative management (29.3%) [1]
- High surgical risk / critically ill: Percutaneous cholecystostomy tube as bridge or definitive therapy; however, higher complication rates (65%) vs. cholecystectomy (12%) [1][17]
- Delayed cholecystectomy: If ELC not feasible, delay at least 6 weeks from acute presentation [2][13]
The following figure illustrates the Tokyo Guidelines severity-based management algorithm:
17. Disposition
- Admit (most patients): Confirmed acute cholecystitis for IV antibiotics, surgical consultation, and ELC
- ICU admission: Grade III (severe) cholecystitis with organ dysfunction, sepsis, hemodynamic instability [16]
- Observation: Equivocal diagnosis awaiting HIDA scan or serial exams
- Surgical consultation: All confirmed cases — urgent for peritoneal signs, gangrenous/perforated cholecystitis [26]
- GI consultation: If concern for choledocholithiasis (for ERCP) or need for endoscopic gallbladder drainage
- Discharge considerations: Rarely appropriate from the ED for confirmed acute cholecystitis; patients with biliary colic (pain resolved, normal labs, no US signs of cholecystitis) may be discharged with urgent surgical follow-up
18. Follow Up / Return Precautions
- Post-cholecystectomy: Surgical follow-up in 1–2 weeks
- If discharged with biliary colic: Surgical consultation within 1–2 weeks for elective cholecystectomy; ~30% of conservatively managed patients develop recurrent gallstone complications [13]
- Return immediately for:
- Worsening or persistent abdominal pain
- Fever, chills, rigors
- Jaundice or dark urine
- Persistent vomiting or inability to tolerate fluids
- Lightheadedness, dizziness, or signs of hemodynamic instability
- Expected course: With ELC, most patients are discharged within 1–3 days; postcholecystectomy syndrome (pain, bloating, diarrhea) occurs in a minority and is usually self-limited [3]
- Long-term: Counsel on dietary modifications for gallstone prevention in patients with risk factors
References
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