Autoimmune hepatic disease Flashcards
What is autoimmune hepatitis? Characterised by? (x4)
CHRONIC inflammatory disease of the liver of unknown aetiology. It is characterised by the presence of circulating auto-antibodies, hyperglobulinaemia, inflammatory changes on liver histology, and a favourable response to immunosuppressive treatment.
What is hyperglobulinaemia?
High concentration of circulating globulins – mostly this concerns immunoglobulins.
What is the difficulty with identifying and managing autoimmune hepatitis clinically?
Disease has variable course and different clinical manifestations.
What is the aetiology of autoimmune hepatitis? (x4)
- Unknown but likely a complex interaction between the following:
- (1) Genetic predisposition: HLA genes on Chr6 – Type 1 associated with HLA-DR3 and HLA-DR4; Type 2 with HLA-DQB1 and HLA-DRB.
- (2) Environmental triggers including viruses (measles, hepatitis) and drugs (some antibiotics and statins)
- (3) Auto-antigens (normal protein that is abnormally recognised by the immune system): autoantibodies against ASGP-R, CYP2D6, and UDP-glucuronosyltransferases.
- (4) Dysfunction of immunoregulatory mechanisms e.g., as part of APECED syndrome’s pathophysiology.
What is the pathophysiology of autoimmune hepatitis?
Hepatocyte expression of HLA antigens become the focus of a principally T-cell mediated autoimmune response. Auto-antibodies lead to chronic inflammatory changes of the liver, lymphoid infiltration of the portal tracts and hepatocyte necrosis, leading to cirrhosis.
What are the classifications of autoimmune hepatitis? (x2)
- Classified according to the pattern of autoantibodies present
- Type 1: ANA, anti-smooth muscle antibody (ASMA), perinuclear anti-neutrophil cytoplasmic autoantibody, anti-actin antibodies (AAA), and anti-soluble liver antigen (anti-SLA)
- Type 2: anti-liver kidney microsomal-1 (anti-LKM) and anti-liver cytosol specific-positive (ALC-1)
What is the epidemiology of autoimmune hepatitis: Ethnicity? Prevalence? Age? (x2) Gender?
Highest prevalence in northern European ancestries. 16.9 per 100,000. Most commonly 10-30 y/o and 40-60 y/o for Type 1; 2-14 y/o for Type 2. Very high ratio are females.
What percentage of autoimmune hepatitis patients present acutely?
25% with acute hepatitis. Remaining are asymptomatic or have insidious onset and picked up on abnormal LFTs.
What are the symptoms of autoimmune hepatitis? (x4)
- Remember, presentation is variable.
- Insidious onset: malaise, anorexia, nausea, jaundice, amenorrhoea, epistaxis
- Acute hepatitis: fever, anorexia, jaundice, nausea, diarrhoea, RUQ pain. Some may also present serum sickness e.g., arthralgia, polyarthritis, maculopapular rash.
- May be associated with keratoconjunctivitis sicca.
- Personal or family history of autoimmune disease such as T1DM.
What is keratoconjunctivitis sicca?
Dryness of conjunctiva and cornea.
What are the signs of autoimmune hepatitis?
- Stigmata for chronic liver disease such as spider naevi
- Ascites, oedema and encephalopathy are late features – all associated with portal hypertension
- Cushingoid features e.g., rounded face, cutaneous striae, acne, hirsutism, may be present even before the administration of steroids
What are the blood investigations for autoimmune hepatitis? (x4)
- LFT: in serious disease – very increased AST, ALT and GGT, high AlkPhos, high bilirubin, low albumin
- Clotting: increased PT in severe disease
- FBC: mild decreased Hb, low platelets, low WCC (latter two from hypersplenism if portal hypertension present).
- Hypergammaglobulinemia is typical (polyclonal gammopathy) with the presence of ANA, ASMA (Type 1) or anti-LKM antibodies (Type 2).
What is hypergammaglobulinemia?
Increase in serum gamma globulins. Gamma globulins include immunoglobulins, though not all immunoglobulins are gamma globulins, and not all gamma globulins are immunoglobulins.
What is polyclonal gammopathy?
A gammopathy is an abnormal increase in the body’s ability to produce antibodies. A monoclonal gammopathy is an abnormal increase in the production of antibodies using the same type of cell. A polyclonal gammopathy is an abnormal increase in the production of antibodies using many different types of cells.
What are the other investigations for autoimmune hepatitis? Definitive diagnosis? (x2)
- Liver biopsy: needed to establish the diagnosis. Shows interface hepatitis or cirrhosis
- USS, CT or MRI of liver and abdomen: to visualise lesions