Praxis Medical Insights

Diagnosis and Initial Management

The American Gastroenterological Association recommends continuing prednisone therapy at a dose of 60mg daily for at least 4 weeks, as IgG4-related disease typically responds well to corticosteroid therapy, with a common steroid regimen being prednisolone 40mg daily for 2-4 weeks 1
A comprehensive liver panel, including ALT, AST, bilirubin, alkaline phosphatase, and GGT, should be monitored closely, with liver enzymes checked every 1-2 days initially if severely elevated (>5× ULN), as recommended by the European Association for the Study of the Liver (EASL) 2, 1
Serum IgG4 levels and autoimmune markers, such as ANA, ASMA, and ANCA, should be measured to confirm the diagnosis of IgG4-related hepatitis, and coagulation studies should be performed to assess the risk of bleeding in patients with immune-mediated hepatitis 2, 1
Imaging, such as cross-sectional hepatobiliary imaging, may be considered to exclude biliary obstruction, hepatic metastases, and thromboembolic disease, as recommended by the American Gastroenterological Association 3, 1

After 2-4 weeks at the initial dose, prednisone should be tapered by 5mg every week over approximately 8-12 weeks, with slower tapering required if liver enzymes worsen during taper, as recommended by the American College of Gastroenterology 1
The American College of Gastroenterology recommends considering maintenance immunosuppression after initial response, with options including low-dose prednisone (5-7.5mg daily) or addition of a steroid-sparing agent, such as azathioprine (2mg/kg/day) or mycophenolate mofetil, with a target dose of 1.5-2g/day in divided doses 1, 4, 5
Azathioprine (2mg/kg/day) may be considered as a second-line agent, and mycophenolate mofetil (MMF) 1000mg three times daily may be added if no improvement is seen after 3-5 days, or if prednisone is suspected to be causing hepatotoxicity 6, 1, 5
Calcineurin inhibitors, such as tacrolimus or cyclosporine, may be considered if there is no improvement with MMF within 2-3 days, as recommended by the European Association for the Study of the Liver (EASL) 2

Most patients with IgG4-related hepatitis show rapid and favorable disease control after initial corticosteroid therapy, but relapse after cessation of steroid treatment may occur in at least 60% of patients with IgG4-SC, making long-term immunosuppression often required to prevent relapse, as recommended by the American College of Gastroenterology 1
Regular monitoring of liver function tests is essential during treatment and after tapering, with consideration of dose adjustment based on serum albumin levels in severe liver dysfunction, and liver enzymes should be monitored daily or every other day initially, and for AST/ALT >8× ULN, inpatient monitoring should be considered 1, 5

The following grading system is recommended:

Grade	Hepatitis (AST/ALT)	Colitis	Treatment
1	1-3× ULN	Mild	Monitor LFTs weekly, consider holding immunotherapy if symptomatic [3, 5]
2	>3-5× ULN	Moderate	Hold immunotherapy, consider steroids 0.5-1 mg/kg/day [3, 5]
3-4	>5× ULN	Severe	Permanently discontinue immunotherapy, high-dose steroids, consider hepatology consultation and liver biopsy [5, 3]

IgG4-related hepatitis may require more aggressive immunosuppression than typical autoimmune hepatitis, and rituximab may be considered for refractory cases based on expert consultation, as recommended by the European Association for the Study of the Liver (EASL) 2
Multi-organ involvement, such as pancreas, biliary tree, and lungs, is common in IgG4-related disease and should be monitored, and CTLA-4 inhibitors are associated with a higher incidence of hepatitis, up to 10% of cases, particularly in patients receiving ipilimumab, while PD-1 inhibitors, such as nivolumab and pembrolizumab, cause hepatitis in 5-10% of patients 2, 7
Combination immunotherapy, especially CTLA-4 plus PD-1 inhibitors, significantly increases the risk of hepatitis, with an incidence of 25-30% and 15% being grade 3, and avoid infliximab in checkpoint inhibitor hepatitis due to potential hepatotoxicity, as advised by the European Medicines Agency 7, 3, 5
Consider liver biopsy for steroid-refractory cases or when diagnosis is uncertain, as suggested by the American College of Gastroenterology, and permanently discontinue immune checkpoint inhibitors and initiate systemic corticosteroids, such as methylprednisolone 1-2 mg/kg/day, for patients with concurrent immune-related hepatitis and colitis, as recommended by the American Society of Clinical Oncology 5, 7