autoimmune hepatitis Flashcards
definition of autoimmune hepatitis
chronic hep of unknown aetiology
characterside by autoimmune features, hyperglobinaemia, abnormal T cell func and presence of circulating autoAb
classification is by auto-Ab
aeitiology of autoimmune hep
genetically predisposed person, env agent (virus/drugs) = hepatocyte expression of HLA antigens - focus of T cell mediated autoimmune attack
The raised titres of ANA, ASMand anti-liver/kidney microsomes (anti-LKM) are not thought to directly injure the liver.
The chronic inflammatory changes are similar to those seen in chronic viral hepatitis: lymphoid infiltration of the portal tracts and hepatocyte necrosis = fibrosis and, eventually, cirrhosis.
Patients with variant forms of autoimmune hepatitis have clinical and serologic findings of autoimmune hepatitis plus features of PBC or PSC
Ab in type 1 hep
ANA
anti-smooth muscle Ab (ASMA)
anti-actin Ab (AAA)
anti-soluble liver ag (anti-SLA)
Ab in type 2 autoimmune hep
Ab to liver/kidney microsomes (ALKM-1, directed at an epitope of CYP2D6)
Ab to a liver cytosol Ag (ALC-1)
associations and RF for autoimmune heop
pernicious anaemia
UC
glomerulonephritis
autoimmune thyroiditis
autoimmune haemolysis
dm
PSC
HLA A1 B8 and DR3 haplotype
female
genetic predisposition
immune dysregulation
measles
cytomegalovirus
EBV
hep A C D viruses
drugs
epidemiology of autoimmune hep
type 1 in all age gps - mainly young women
type 2 - disease of girls and young women
mainly affects 10-30yr or >=40yr women
sx of autoimmune hep
may be asymptomatic - incidental by LFT
insidious onset
- malaise
- fatigue
- anorexia
- weight loss
- nausea
- jaundice
- amenorrhoea, disease attenuates in preg
- epistaxis
keratoconjunctivitis sicca
personal/FH autoimmune - T1dm, vitiligo
full history to rule out other causes of hep - alcohol/drugs
acute autoimmune hep sx
fever
anorexia
jaundice
nausea
vom
diarrhoea
RUQ pain
pleuracy
pul infiltration
glomerulonephritis
serum sickness - arthralgia, polyarthritris, maculopapular rash
signs of autoimmune hep
stigmata of chronic liver disease eg spider naevi
ascites, oedema and encephalopathy are late features
Cushingoid features (e.g. rounded face, cutaneous striae, acne, hirsuitism) may be present even before the administration of steroids
ix for autoimmune hep
blood
liver biopsy - needed to establish the ddx - shows interface hep/cirrhosis
viral serolgy
caeruloplasmin and urinary copper - wilson’s
ferritin and transferrin saturation - haemochromatosis
a1-antitripsin (a1-antitripsin def)
antimitochondrial Ab (PBC)
US, CT, MRI liver and abdo - visualise structural lesions
ercp - rule out PSC
Mononuclear infiltrate of portal and periportal areas and piecemeal necrosis ± fibrosis; cirrhosis ≈worse prognosis.
MRCP: Helps exclude PSC if ALP raised disproportionately
bloods for autoimmune hep
LFT: raised AST, ALT, GGR, alkphos, BR. low albumin in severe disease
clotting: raised PT in severe disease
FBC: mild low Hb, low platelets and WCC from hypersplenism if portal hypertension present
hypergammaglobuminaemia especially IgG - typical (polyclonal gammopathy) with presence of ANA, ASMA or anti-LKM Ab
mx of autoimmune hep
immunosuppression - pred / azathioprine
vaccination against hep a and b
ca and vit d supplements
dexa scans
check for glaucoma and cataracts
liver transplant
what is mod-severe autoimmune hep
- AST >5 times the normal serum level
- Immunoglobulins >2 times the normal serum level
- Liver biopsy showing necrosis
