Gallstone Pancreatitis

Acute pancreatitis caused by a gallstone or sludge passing through, or impacting at, the ampulla of Vater, with obstruction of the pancreatic duct and reflux of bile.

• The commonest cause of acute pancreatitis worldwide (about 40%, and more in women and older patients); about 3 to 7% of people with gallstones develop pancreatitis, and the risk is highest with small stones (less than 5 mm) and microlithiasis.
• Risk is highest in the first weeks after symptoms; recurrence without definitive treatment is about 30 to 50% in the next 6 months.
• Mechanism: transient obstruction of the ampulla by stone passage raises pancreatic duct pressure and triggers premature enzyme activation, inflammation and, in severe cases, necrosis; persistent impaction produces cholangitis.
• Severity: about 80% mild, 15 to 20% moderately severe or severe; severe disease has mortality of about 20 to 40%.

Sudden epigastric pain radiating to the back, often after a fatty meal or at night, with nausea and vomiting; previous biliary colic or jaundice.

• Fever, jaundice, and right upper quadrant pain (the Charcot triad) indicate cholangitis; hypotension and confusion add to Reynolds pentad.
• Examination: epigastric tenderness, guarding, reduced bowel sounds, tachycardia, jaundice, Murphy sign in coexisting cholecystitis.
• Differential diagnosis: acute cholecystitis, biliary colic, cholangitis alone, perforated ulcer, bowel obstruction, mesenteric ischaemia, inferior myocardial infarction, aortic dissection, alcoholic and other causes of pancreatitis.
• Complications: cholangitis, necrotising pancreatitis, infected necrosis, pseudocyst, organ failure, persistent common bile duct stone, recurrent attacks, and gallstone ileus (rare).

Lipase of more than 3 times the upper limit of normal, with typical pain; alanine aminotransferase of more than 150 U/L (or 3 times normal) predicts a gallstone cause with about 95% positive predictive value; bilirubin, alkaline phosphatase and gamma glutamyl transferase rise with duct obstruction.

• Transabdominal ultrasound within 24 hours: gallstones or sludge, gallbladder wall thickening, common bile duct dilatation (more than 6 mm, or more than 8 mm after cholecystectomy), common bile duct stone.
• MRCP or endoscopic ultrasound when stones are not seen but a biliary cause is suspected, or when the common bile duct is dilated with abnormal liver tests; both are preferred to diagnostic endoscopic retrograde cholangiopancreatography, which carries a 3 to 5% risk of pancreatitis.
• Blood tests for severity (full blood count, urea, creatinine, calcium, glucose, C-reactive protein, lactate), blood cultures if febrile, and triglycerides to exclude a second cause.
• CT with contrast at 72 hours or more for suspected necrosis or complications.

Fluids: lactated Ringer solution 5 to 10 mL/kg/hour for 12 to 24 hours, with reassessment every 6 hours for urine output of more than 0.5 mL/kg/hour, mean arterial pressure of 65 to 85 mmHg, and falling urea; avoid excess fluid.

• Analgesia: paracetamol 1 g IV or oral every 6 hours (maximum 4 g daily); morphine 2 to 5 mg IV every 2 to 4 hours as needed, or fentanyl 25 to 50 micrograms IV, or hydromorphone 0.5 to 1 mg IV.
• Nutrition: oral low fat diet within 24 hours as pain allows; nasojejunal or nasogastric enteral feeding (30 kcal/kg/day) if intake fails after 48 to 72 hours.
• Oxygen to SpO2 94 to 98%; enoxaparin 40 mg SC daily for thromboprophylaxis; monitoring for organ failure; critical care for persistent failure.
• Biliary decompression:
  • Cholangitis or biliary sepsis: endoscopic retrograde cholangiopancreatography with sphincterotomy and stone extraction within 24 hours, plus antibiotics (ceftriaxone 2 g IV daily with metronidazole 500 mg IV every 8 hours, or piperacillin-tazobactam 4.5 g IV every 6 hours, or meropenem 1 g IV every 8 hours for severe illness) for 4 to 7 days after drainage.
  • Persisting common bile duct obstruction (bilirubin rising or more than 85 micromol/L (5 mg/dL), or a stone seen on imaging) without cholangitis: endoscopic retrograde cholangiopancreatography within 72 hours.
  • No urgent endoscopic retrograde cholangiopancreatography for mild disease without obstruction or cholangitis; protect the pancreas during the procedure with rectal indomethacin 100 mg and a prophylactic pancreatic stent in high-risk patients.
• No prophylactic antibiotics; antibiotics for infected necrosis: meropenem 1 g IV every 8 hours for 2 to 4 weeks, guided by culture.
• Definitive treatment (prevents recurrence):
  • Mild disease: laparoscopic cholecystectomy during the same admission (within 2 to 4 days of recovery, with intraoperative cholangiography where common bile duct stones are possible).
  • Moderately severe or necrotising disease: delay cholecystectomy until collections have resolved or stabilised (about 6 weeks, or 4 weeks if collections are absent), with a planned operation after discharge.
  • Patients unfit for surgery: endoscopic sphincterotomy lowers recurrent pancreatitis but not other biliary events.
• Necrotising pancreatitis and collections: manage by drainage after 4 weeks when infected or causing obstruction (endoscopic transluminal drainage with a lumen-apposing metal stent, then necrosectomy); percutaneous drainage as a bridge.
• Special groups: children (stone or sludge, usually haemolytic disease, obesity or cystic fibrosis; ursodeoxycholic acid 10 to 15 mg/kg/day in two doses, cholecystectomy); pregnancy (fluids, paracetamol, endoscopic retrograde cholangiopancreatography with lead shielding for cholangitis, laparoscopic cholecystectomy in the second trimester, ursodeoxycholic acid 10 to 15 mg/kg/day when surgery is delayed); elderly (higher risk of severe disease, early decompression, laparoscopic surgery when fit); renal impairment (adjust antibiotics, avoid NSAIDs); cirrhosis (higher risk, specialist care).
• Red flags: fever and jaundice, persistent organ failure, bilirubin rising, shock, bleeding, infected necrosis, failure to improve in 72 hours.
• Follow-up: liver tests and clinical review at 1 to 2 weeks; confirm cholecystectomy date before discharge; repeat ultrasound if jaundice persists; imaging at 6 weeks for collections; dietary advice (low fat), weight management, and stopping alcohol.