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Investigation of Liver Function

From Mediwikis

Liver and pangreas - transparent.png

Core conditions


Discriminating Symptoms

  • Abdo pain, fever and rigors → biliary colic, cholangitis
  • Pruritus (itch) → cholestatic disease
  • Arthritis/arthralgia → haemochromatosis, Hep B, autoimmune hepatitis
  • Pigmentation → Primary biliary cirrhosis, haemochromatosis
  • Bloody diarrhoea → Primary sclerosing cholangitis (80% of patients also have IBD)
  • Weight loss → malignancy
  • SOB → alpha 1 anti trypsin deficiency
  • Dry eyes and mouth → Primary biliary cirrhosis (lots of cases associated with Sjorgen’s syndrome, which causes dry eyes and mouth)

Imaging

Ultrasound

  • 1st line investigation
  • Good for looking at organs
  • Can see stones and malignancies
  • Can also assess blood flow using Doppler

CT

  • Excellent for focal liver lesions
  • Can assess liver architecture
  • Can see vasculature, varices and portal hypertension

MRI

  • Best investigation for focal liver lesions, but some patients find it difficult to do, as they need to lie still and hold their breath for some time
  • Good investigation for biliary tree

Liver biopsy

  • Used only in chronic disease (not acute) to assess cause and severity, as well as in focal lesions and post transplant in cases of rejection

Blood tests

Autoantibodies:

  • ANA (anti nuclear antibody) and anti SMA (anti smooth muscle antibody) in autoimmune hepatitis
  • AMA (anti mitochondrial antibody) in primary biliary cirrhosis
  • p-ANCA in primary sclerosing cholangitis

Immunoglobulins:

  • Raised IgG - in hepatitis viruses and autoimmune hepatitis
  • Raised IgM – in primary biliary cirrhosis and hepatitis viruses
  • Raised IgA – alcoholic liver disease

Iron and Copper studies

  • Raised ferritin and raised transferrin saturation in haemochromatosis
  • Low caeruloplasmin in Wilson’s disease

Tumour markers:

  • α fetoprotein +ve in 50-80% of hepatocellular carcinomas
  • CA19-9 +ve in cholangiocarcinomas

Clotting studies:

  • Raised APTT (measures intrinsic pathway) - liver produces factors II, VII, IX and X

Bilirubin:

  • >17 = abnormal
  • >30 = clinical jaundice
  • Raised unconjugated bilirubin in pre hepatic jaundice (haemolysis) and Gilbert’s syndrome (a hereditary condition that causes a reduced activity of the enzymes that conjugate bilirubin)
  • Raised mixed bilirubin in hepatic jaundice
  • Raised conjugated bilirubin in [Obstructive Jaundice]
  • A bilirubin ten times higher than normal can indicate neoplastic or intrahepatic cholestasis.


LFTs

AST/ALT

  • The transaminases
  • Evidence of hepatocellular damage
  • ALT is typically lower than AST
    • An ALT that is higher than the AST is a sign of hepatitis
    • A really high AST (AST:ALT > 10:1) is a sign of alcoholic liver damage
  • ALT/AST levels do not correlate to the extent of the disease, however, a sudden drop from previously high levels can indicate necrosis.

Alk phos/Gamma GT

  • Raised alk phos and gamma GT indicate cholestasis
  • A very high alk phos indicates obstruction

Alk phos and ALT/AST can be elevated in non-liver conditions (such as some bone and heart problems). Gamma GT is used to differentiate between non-liver and liver conditions, as it is normally only raised in liver problems. Both alk phos/gamma GT and ALT/AST are commonly raised in all sorts of liver conditions, but you must look at the highest of the results to see what type of liver disease is indicated.