Page created on April 20, 2022. Last updated on December 18, 2024 at 16:58

Autoimmune hepatitis

Introduction and epidemiology

Autoimmune hepatitis (AIH) is a cause of hepatitis which presents acutely but becomes chronic, possibly progressing to cirrhosis.

AIH mostly affects females. It can present at any year but mostly begins in the teens or in elderly. As with most autoimmune diseases, there is associated with other autoimmune diseases.

It has a good response to therapy and a good prognosis, but a 40% mortality rate if untreated. 70% of patients relapse at some point after having reached remission.

Etiology

The development of AIH often involves an environmental trigger (viral infection, drug, etc.) in a genetically susceptible person. The following alleles are associated with AIH:

• HLA-B8
• HLA-DR3
• HLA-DR4

Clinical features

AIH may present asymptomatically (only abnormal laboratory parameters), as acute hepatitis, or with cirrhosis.

Some extrahepatic manifestations of AIH include:

• Vitiligo
• Acne
• Vasculitis
• Erythema nodosum
• Rheumatological disease

Diagnosis and evaluation

As with any hepatitis, liver enzymes (AST, ALT, GGT, ALP) are elevated. AST and ALT may be significantly elevated, often >10x the upper limit of normal. However, the following findings are typical for AIH:

• Autoantibodies (ANA, SMA)
• Hypergammaglobulinaemia

Biopsy and histology are obligatory to confirm the diagnosis, to determine the activity and stage, and to exclude other diseases. Typical for AIH is lymphocytic infiltration in the portal tract.

Treatment

Immunosuppressive therapy to induce and maintain remission is indicated, in all but very mild cases. Remission is induced with glucocorticoids ± azathioprine and maintained with azathioprine or other immunosuppressants. Once remission has been maintained for a long time (>18 months), drug withdrawal may be attempted as many don’t require long-term immunosuppressive therapy to prevent relapse.

In very severe cases, liver transplantation is an option.

Primary biliary cholangitis

Introduction and epidemiology

Primary biliary cholangitis (PBC), previously known as primary biliary cirrhosis, is an autoimmune chronic liver disease characterised by progressive destruction of intralobular bile ducts leading to intrahepatic cholestasis. Eventually, cirrhosis develops.

It almost exclusively affects middle-aged women and is associated with other autoimmune disorders.

Clinical features

PBC may present asymptomatically (only abnormal laboratory parameters) as it remains asymptomatic for a long time. Then, nonspecific symptoms like fatigue and pruritus appear. Later, symptoms of cholestasis appear, like jaundice, itching, and xanthelasmas.

Diagnosis and evaluation

As with any cholestasis, ALP, GGT, and bilirubin are elevated. However, the following findings are typical for PBC:

• Autoantibodies (ANA, AMA)
• Hyperlipidaemia
• Mildly increased AST and ALT

Symptoms of cholestasis often prompts morphological examination of bile ducts with ERCP or MRCP, but these are normal in case of PBC. Ultrasound can also be used to in the evaluation

Biopsy and histology are not necessary for the diagnosis but may give information on stage and prognosis. It will show destruction of the interlobular bile ducts.

Treatment

There is no cure for PBC, and so treatment aims at slowing disease progression and improving symptoms.

Ursodeoxycholic acid (UDCA) is a hydrophilic bile acid which stimulates bile secretion and has a hepatoprotective effect and is used in the treatment of PBC. It slows the progression and improves the symptoms. Obetichoic acid is another option.

Cholestatic pruritus is a common and possibly disabling symptom. UDCA improves it, but bile acid sequestrants like cholestyramine or rifampin may also help.

Liver transplantation is the only definitive treatment but is reserved for end-stage disease or intractable pruritus.