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lfts

liver function tests (LFTs)

introduction

Ix of the patient with "hepatitic picture"

Ix of the patient with a "cholestatic picture":

  • the most common cause of “cholestatic picture” is biliary, thus a biliary USS is indicated to exclude cholelithiasis (gallstones) or CBD obstruction due to other causes
  • USS shows dilated CBD:
  • if biliary USS normal:
    • it may still be extrahepatic cholestasis with normal CBD and intrahepatic duct diameters if either:
      • partial obstruction of the bile duct
      • scarred ducts preventing the ducts from dilating
        • eg. cirrhosis or primary sclerosing cholangitis
    • causes of intrahepatic cholestasis:
      • primary biliary cirrhosis (PBC) - check antimitochondrial antibodies and if +ve, consider liver biopsy
      • primary sclerosing cholangitis - consider MRCP to Dx
      • infiltrative diseases:
      • drug toxicity
      • viral hepatitis
      • cholestasis of pregnancy
      • benign postoperative cholestasis
      • total parenteral nutrition

Ix of isolated raised GGT

  • an isolated raised GGT levels is usually not worth extensive Ix as it tends to be non-specific and occurs in:
    • pancreatic disease
    • myocardial infarction
    • renal failure
    • chronic obstructive pulmonary disease
    • diabetes mellitus
    • alcoholism
    • patients taking medications such as phenytoin and barbiturates

Ix of isolated raised AP

  • exclude raised AP arising from bone:
    • children and adolescents with rapidly growing bones
    • those with healing bone fractures
    • those with bone disorders such as osteomalacia, etc.
      • these patients may require work up for these bone conditions
  • isolated raised AP arising from the liver may occur in:

Ix of isolated hyperbilirubinaemia

  • determine if bilirubin is mainly:
    • conjugated (“direct hyperbilirubinaemia”):
      • due to:
        • decreased excretion into the bile ductules
          • Dubin-Johnson syndrome
        • leakage of conjugated bilirubin from hepatocytes into serum
        • Rotor syndrome
    • unconjugated (“indirect hyperbilirubinaemia”):
      • due to:
        • bilirubin over-production:
          • haemolysis
            • haemolytic anaemia - check urine for Hb, and check blood reticulocyte count
            • emphysematous cholecystitis - mild to moderate unconjugated hyperbilirubinemia may be present because of haemolysis induced by clostridial infection
          • ineffective haematopoiesis
        • impaired bilirubin uptake into liver or conjugation:
          • Gilbert's disease (especially during periods of stress)
          • Crigler-Najjar syndrome
          • drugs

Ix of isolated hypoalbuminaemia

1)
Dig Dis Sci. 1979;24(11):835
lfts.txt · Last modified: 2020/05/24 17:28 by gary1