Autoimmune Hepatitis Unmasked by Acute Viral Hepatitis: A Diagnostic and Therapeutic Challenge

Autoimmune hepatitis (AIH) is a rare disease with unclear pathogenesis. Acute viral hepatitis (AVH) can trigger autoimmunity and unmask underlying AIH, which can be difficult to recognize due to overlapping clinical features.

This case series included 10 patients diagnosed with AIH following confirmed AVH. Demographics, clinical presentation, investigations, biopsy results, and treatment outcomes were analyzed. Diagnosis of AIH was established using the simplified AIH score.

The cohort included seven patients with hepatitis A virus, two with hepatitis E virus, and one with hepatitis B virus. Mean age was 26.9 ± 10.6 years with male predominance (n = 7,70%). Median time to AIH diagnosis was 82 (68-125) days after initial symptoms. Serum immunoglobulin G was elevated in all patients [median: 1834.5(1138-3858 mg/dL); normal <1700 mg/dL]. Anti-nuclear antibody was positive in 40%, anti-smooth muscle antibody in 30%, with 40% being seronegative. Liver biopsies showed interface hepatitis (90%), lobular inflammation (100%), and lymphoplasmacytic infiltrate (100%). Fibrosis (Metavir scoring system) stages were F0 (30%), F1 (20%), F2 (30%), and F3 (20%). All patients achieved complete biochemical remission with prednisolone (dose: 0.5-1 mg/kg/day, and azathioprine (dose: 1-2 mg/kg/day, median initiation time: 45 days after prednisolone start). One attempt at immunosuppression withdrawal resulted in flare.

AVH can unmask underlying AIH and protracted course beyond the expected course of AVH for prompt evaluation of AIH. Standard immunosuppressive therapy is generally effective and long-term maintenance treatment may be required.