Synopsis
Diagnose autoimmune hepatitis rigorously, identify acute liver failure and use monitored induction and maintenance immunosuppression to prevent progressive fibrosis.
- Autoimmune hepatitis is an immune-mediated necroinflammatory liver disease that can present at any age, from incidental aminotransferase elevation to acute liver failure.
- The diagnosis combines biochemistry, immunoglobulin G, autoantibodies, compatible histology and deliberate exclusion of viral, metabolic, obstructive and drug-related liver injury.
- Antinuclear and smooth-muscle antibodies support type 1 disease; anti-LKM1, anti-LC1 or anti-SLA can help in selected seronegative or atypical presentations.
- Normal IgG or negative conventional antibodies does not exclude acute autoimmune hepatitis, especially early in a severe presentation.
- Interface hepatitis with lymphoplasmacytic inflammation is characteristic but not pathognomonic; biopsy interpretation must include the clinical differential and recent medicines.
- The simplified AIH score organises evidence but should not replace expert judgement, particularly in acute, cholestatic, paediatric or overlap phenotypes.
- Prednisolone is standard induction; the 2025 BSG guideline recommends approximately 0.5 mg/kg once each morning and usually no more than 40 mg daily for typical adults.
- Azathioprine provides steroid-sparing maintenance after thiopurine-methyltransferase assessment and requires structured blood-count and liver-test monitoring.
- Biochemical remission means normal aminotransferases and IgG, not merely improvement; persistent low-grade activity can continue fibrosis silently.
- Stopping treatment is considered only after sustained complete remission and specialist review because relapse is common and some patients need lifelong immunosuppression.
Key red flags
Fatigue, anorexia, nausea, right-upper-quadrant discomfort, dark urine, jaundice and arthralgia accompany a predominantly hepatocellular biochemical injury.
New jaundice with INR prolongation but no encephalopathy requires urgent inpatient hepatology assessment and close trajectory monitoring.
Coagulopathy plus any altered behaviour, sleep reversal, confusion, asterixis or coma in a person without known cirrhosis needs immediate transplant-centre discussion.
Splenomegaly, thrombocytopenia, ascites, varices, muscle loss or a nodular liver may reveal longstanding disease despite modest current aminotransferases.
Investigation priorities
Define injury pattern, severity and trajectory.
Management branches
A hepatitic blood pattern, raised IgG or unexplained inflammatory hepatitis raises autoimmune hepatitis.
- Assess jaundice, encephalopathy, INR, glucose and haemodynamics first and admit urgently when synthetic function is impaired.
- Obtain IgG and a structured autoantibody panel while excluding viral hepatitis, Wilson disease where relevant, biliary obstruction, alcohol and medicine or supplement injury.
- Arrange liver biopsy through the safest route when it will confirm activity, fibrosis or overlap and does not delay emergency care.
- Integrate findings with an AIH score as support, then have a hepatologist resolve seronegative, cholestatic, acute severe and drug-triggered uncertainty.