APPROACH TO ABNORMAL LIVER FUNCTION TESTS IN FAMILY PRACTICE


Dr.S.ABBAS ALI
MD, DFM, DNB(FAM.MED)
MNAMS (Family Medicine)
FCGP, MCCP (Cardiology)
PGDHSc(Ultrasonography)
PGDHSc(Echocardiogram)


Abnormal LFTs are common observation in family practice. It can be present in majority of patients with no symptoms and in some patients with minor symptoms like lethargy, pruritis, abdominal pain, low grade fever. An expert family physician with the help of detailed history and physical examination can suspect potentially fatal diseases like cirrhosis, primary biliary cirrhosis, primary sclerosing cholangitis, and liver tumors and by following cardinal principles of family practice like referral, sharing of responsibility and continued follow up may save patients lives with liver problems.
I. TEST FOR HEPATOCELLULAR INJURY
Aminotransferases: Alanine aminotransferase (ALT) and Aspartate Aminotransferase (AST) are released in blood stream after hepatocellular injury. Increased ALT activity reflects hepatic damage more specific.
II. TEST FOR CHOLESTASIS
Serum alkaline phosphatase: this enzyme situated in the canicular and sinusoidal membrane of liver cells. A greatly increased alkaline phosphatase activity is main biochemical indicator of biliary obstruction.
Gamma glutamyl transferase: increased plasma GGT occur in biliary obstruction and acute parenchymal damage from any cause

III. TEST FOR HEPATIC FUNCTION
They help in predicting prognosis
Serum albumin: decreasing levels indicate poor prognosis
Serum Bilirubin: increasing levels indicate poor prognosis
Prothrombin time (PT): increasing levels indicate poor prognosis
IV.CHOLESTASIS PREDOMINANT LIVER INJURY
ALT and AST levels are mildly elevated. Serum alkaline phosphatase and GGT levels are high.
Primary biliary cirrhosis: suspect if middle aged women of 50 years with autoimmune disorder like hypothyroidism, Rheumatoid arthritis etc with complaints of lethargy, pruritis, abdominal pain, low grade fever and increased serum alkaline phosphatase. Antimitochondrial antibody (AMA) positive. These patients should be referred to particular subspeciality for further evolution without delay. The definitive treatment was Liver transplantation. It should be considered as early as possible to minimize morbity and mortality. In PBC interlobular bile ducts are damaged by chronic granulomatous inflammation causing progressive cholestasis, cirrhosis and portal hypertension.
Primary sclerosing cholangitis: PSC is a disorder of unknown cause characterized by non malignant non bacterial inflammation, fibrosis and stricture of the intra and extra hepatic bile ducts.
Suspect if middle aged men with autoimmune disorder especially ulcerative colitis with elevated serum bilirubin and serum alkaline phosphatase with no symptoms or with fluctuating symptoms like lethargy, pruritis, abdominal pain and jaundice. P-ANCA is positive. There is no curative medical therapy and liver transplantation is the only option for survival and it should be considered early to minimize morbidity and mortality.
Secondary biliary cirrhosis:this develops after prolonged large duct biliary obstruction due to gall stones, bile duct strictures and sclerosing cholangitis.
Liver tumors: ultrasound of abdomen and abdominal CT are helpful. Alpha feto protein levels are increased in hepatocellular carcinoma.
Screening tests for chronic liver disease
HBV & HCV serology
Haemogram and iron studies for haemochromatosis: in Haemochromatosis ↑ferritin ↑iron ↓total iron binding capacity
Alpha 1 antitrypsin deficiency
Wilson diseases: serum copper low, serum ceruloplasmin low and urinary copper ↑
PBC: ↑AMA ( anti mitochondrial antibody)
PSC: ↑P-ANCA ↑ANA ↑AMA
AIH: ↑ANA ↑ASMA (anti smooth muscle antibody) ↑IgG
Immunoglobulins: ↑IgA in alcoholic liver disease ↑IgM in PBM and ↑IgG in autoimmune hepatitis (AIH)
Hepatocellular carcinoma: increased alpha fetoprotein
V.HEPATOCELLULAR PREDOMINANT LIVER INJURY
High levels of AST and ALT usually observed. If levels are high evaluate further by advising viral markers.
Acute viral hepatitis: AST and ALT raised. Serum bilirubin may be normal. Viral markers positive.
Chronic viral hepatitis: Hepatitis B & C are most common causes of abnormal LFT
Alcoholic liver disease: AST /ALT ratio is typically 2:1 or more. When the history is not reliable, normal serum alkaline phosphatase, ↑↑GGT and macrocytosis suggest this condition.
Fatty liver: is the most common cause mild abnormality of LFT in general population. Risk factors of nonalcoholic fatty liver include obesity, DM and ↑Lipids (triglycerides)
Autoimmune hepatitis: AIH occurs mainly in young and middle aged females with concomitant autoimmune disorders (eg. Rheumatological disorders, autoimmune thyroiditis)
Ischaemic hepatitis: can be seen in condition when effective circulatory volume is low (eg. MI, Hypotension, haemorrhage) AST, ALT and LDH raised.
Toxic hepatitis: paracetamol overdose is the main cause. History is vital.
Management and follow up
Manage according to specific diagnosis: If patient is asymptomatic and all the initial evaluation are negative then features of opportunistic health promotion and prevention are followed eg. life style modification, give help for reducing weight, alcohol, smoking, control DM, control hyperlipidaemia, and stop potentially hepatotoxic medication. Repeat test after 3 months, if abnormalities persists do an Ultrasound, abdominal CT has role. If the diagnosis is not apparent or the suspected diagnosis is beyond the reach of family practice then further testing is needed. In this cases cardinal principles of family practice like timely referral, sharing of responsibility, continued follow up are followed. This type of attitude may save patients lives with liver problems.

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