Abnormal Liver Function Tests

1.  Often abnormal LFTs accompany specific symptoms
2.  Sometimes abnormal LFTs can be seen in well/asymptomatic patients and warrant further investigation
3.  In these patients, the abnormal test may herald an underlying disease and it is then prudent to make a diagnosis to make prognostic and therapeutic decisions.
4.  Causes of abnormal LFTs:
   1. o Common: fatty liver, alcohol abuse*, Hep C virus infection, drug reactions
   2.  CAGE Questionnaire – ever felt the need to: Cut down, Anger when told to cut down, Guilt over drinking, Eye opener in the morning?
   3. o Uncommon: haemochromatosis, chronic Hep B infection, primary biliary cirrhosis
   4. o Rare: alpha-1 antitrypsin deficiency
   5. o Primary sclerosing cholangitis
5.  Clinical features:
   1. o Assess amount of alcohol taken – always under-reported by patient
   2. o Any features suggesting Hep B, C: foreign travel (Far East/Africa), sexual preferences and IVDU (past or present) – even if only tried once.
   3. o Jaundice: past or present?
   4. o Full DH: including OTC, herbs and alternative therapies
   5. o FH of liver disease, multi-organ disease, alcohol use, DM (=haemochromatosis), or emphysema (=a1 antitrypsin def)
6.  Ix:
   1. o LFTs:
   2.  Isolated rise in AST or ALT = hepatic pattern
   3.  Isolated rise in alkaline phosphatase = cholestatic pattern
   4.  Rise in gamma-GT, ethanol levels and raised MCV = alcohol pattern
   5. o Viral serology = Hep A does not cause persistently abnormal LFTs – but Hep B&C do.
   6. o Autoantibodies and immunoglobulins: primary biliary cirrhosis may follow an indolent ‘pre-clinical’ course, raised anti-mitochondrial antibodies, raised IgM levels.
   7. o Iron studies: to detect haemochromatosis – due to inborn error of metabolism
   8.  

1. o a1-AT levels: linked to liver disease and pan-acinar emphysema
2. o Fasting glucose: DM can = abnormal LFTs, as can obesity and oddly starvation
3. o Depressed albumin or prolonged prothrombin: indicates serious liver disease and obligate need for histological diagnosis. Lipid profile is often deranged in significant chronic liver disease
4. o Liver USS: use to exclude focal liver abnormality – such as malignancy
5. o Liver biopsy: definitive way to determine prognosis. It is customary to document 6-12/12 of abnormal LFTs before doing biopsy. Not always needed.

 

Useful tests in asymptomatic liver disease: (Disease – test – results [Alkaline phosphatase/AST/gamma-GT])

1.  Hep B/C – viral serology – normal to mild rise/mild to moderate rise/normal to mild rise
2.  Primary biliary cirrhosis – antimitochondrial antibody and raised IgM – massive rise/normal to mild rise/massive rise
3.  Primary sclerosing cholangitis – ERCP – massive rise/mild rise/massive rise
4.  Autoimmune hepatitis – antinuclear antibody and raised IgG levels – normal/moderate rise/mild rise
5.  Haemochromatosis – Fe studies – normal/mild rise/normal
6.  a1-AT def – a1-AT levels – mild rise/moderate rise/mild rise
7.  Alcohol – ethanol level and MCV – moderate rise/moderate rise/massive rise

 

LFTs – a few other ideas…

1.  Synthetic ability of liver = test albumin and INR (ability to coag). If abnormal = consider chronic liver disease. E.g cirrhosis.
2.  Hepatic enzymes = AST/LDH. If abnormal consider hepatitis (viral or autoimmune)
3.  Cholestatic enzymes = alkaline phosphatase. If abnormal consider cholestasis (intra- or extra-hepatic obstruction), or hepatic mets
4.  Inducible enzymes – gamma-GT. If abnormal consider drug [anticonvulsant]/alcohol abuse
5.  Elevated bilirubin. Consider haemolysis, Gilbert’s syndrome, all other advanced liver diseases