What is the management of autoimmune pancreatitis (AIP) with jaundice, abdominal pain, elevated Immunoglobulin G4 (IgG4), and a stricture of the common bile duct?

Management of Autoimmune Pancreatitis with Bile Duct Stricture and Obstructive Jaundice

Initiate corticosteroid therapy with prednisolone 0.6 mg/kg/day (or 30-40 mg/day) as first-line treatment, with concurrent endoscopic biliary stenting via ERCP to relieve the obstructive jaundice from the common bile duct stricture. 1, 2

Initial Management Approach

Confirm the Diagnosis

• Your patient's presentation with elevated IgG4, bile duct stricture, jaundice, and abdominal pain is consistent with IgG4-related sclerosing cholangitis (IgG4-SC), which is part of the autoimmune pancreatitis disease spectrum 3
• Serum IgG4 >4× upper limit of normal is highly specific for IgG4-SC 4, 2
• Before initiating steroids, you must exclude pancreatic cancer and cholangiocarcinoma, as these malignancies can mimic AIP radiographically 5, 6
• Obtain brush cytology and/or endoscopic biopsy during ERCP to exclude malignancy 3

Immediate Biliary Decompression

• Perform ERCP with biliary sphincterotomy and stent placement to relieve the obstructive jaundice 6, 7
• Endoscopic biliary stenting during steroid therapy is both valid and safe, with significantly lower rates of recurrent biliary obstruction (100% vs 82% at 1 month) and acute cholangitis (100% vs 90% at 1 month) compared to stenting without steroids 7
• Administer perioperative antibiotics to prevent cholangitis when instrumenting an obstructed duct 3
• Balloon dilatation of the stricture may be performed in conjunction with stenting 3, 1

Corticosteroid Therapy Protocol

Initial Dosing

• Start oral prednisolone at 0.6 mg/kg/day (typically 30-40 mg/day) for 2-4 weeks 1, 8
• An alternative lower-dose approach of 10-20 mg daily may be considered for elderly patients or those with contraindications like insulin-dependent diabetes or severe osteoporosis 1
• Evaluate treatment response after 2-4 weeks using clinical symptoms, biochemical markers (liver enzymes, bilirubin), and imaging before proceeding with tapering 1

Tapering Schedule

• Reduce prednisolone by 5 mg every 1-2 weeks based on clinical and biochemical response 1, 5, 8
• Taper over 2-3 months to reach a maintenance dose of 2.5-5 mg/day 1, 8
• The corticosteroid response rate is 62-100%, with most patients showing dramatic improvement 1, 5

Maintenance Therapy

• Continue maintenance treatment with low-dose prednisolone (2.5-5 mg/day) plus a steroid-sparing agent for up to 3 years to prevent relapse 1
• Add azathioprine (up to 2 mg/kg/day) as a first-line steroid-sparing agent, starting during prednisolone tapering 1, 3
• Azathioprine is particularly important for patients with proximal extrahepatic and intrahepatic bile duct involvement, who have higher relapse risk 3

Adjunctive Therapies

Ursodeoxycholic Acid

• Add UDCA at 10-15 mg/kg/day for its anticholestatic and anti-inflammatory effects in IgG4-related cholangiopathy 1, 3

Stent Management

• Remove the biliary stent approximately 1 month after initiating steroid therapy, as 96% of patients can have stents safely removed at this timepoint without complications 7
• If the stricture remains unresponsive to medical treatment, repeat endoscopic balloon dilatation may be required 1

Monitoring and Relapse Management

Follow-Up Protocol

• Monitor serological markers (liver enzymes, bilirubin, IgG4 levels) and imaging findings periodically after commencing steroid therapy 5, 8
• Patients achieving complete radiological improvement can discontinue medication, though maintenance therapy is often preferred 5

Managing Relapse

• The relapse rate is approximately 30% during tapering or after withdrawal 1
• Proximal bile duct stenosis and elevated serum IgG4 levels are predictive of relapse 8
• For relapse, re-initiate high-dose corticosteroids tapered to maintenance treatment with low-dose prednisolone (2.5-10 mg daily) plus azathioprine or mycophenolate mofetil 1
• Rituximab induction with or without maintenance rituximab is an alternative for relapsed or steroid-resistant disease 1, 2

Critical Pitfalls to Avoid

• Poor response to steroid therapy should immediately raise suspicion for pancreatic cancer or cholangiocarcinoma, necessitating further examination including possible laparotomy 5
• Do not delay biliary decompression while awaiting steroid response, as obstructive jaundice is a clear indication for both ERCP and steroid therapy 5, 9
• Unlike primary sclerosing cholangitis (PSC), which does not respond to steroids and is associated with inflammatory bowel disease in 70% of cases, IgG4-SC shows prompt clinical and radiographic response to corticosteroids 2
• Avoid futile pancreatic resection by maintaining high clinical suspicion for AIP in elderly patients with obstructive jaundice and pancreatic masses 9