Investigation of the Liver Flashcards
Hepatocytes constitude what percentage of liver mass?
60%
Each hepatocyte is in contact with what other cells?
Sinusoid
Bile canaliculus
Neighbouring hepatocyte
Role of SER
Bilirubin conjugation
Drug detoxification
Carbohydrate metabolism of the liver
Glycogen storage and synthesis
Glycolysis and gluconeogenesis
Protein functions of the liver
Syynthesis and catabolism
Clotting factors
Amino acid metabolism
Urea synthesis
Lipid functions of the liver
Lipoprotein and cholesterol synthesis
Fatty acid metabolism
Bile acid synthesis
What is excreted by the liver
Bile acid and bilirubin
What does the liver do to drugs?
Detoxification and excretion
Inactivates steroids and excretes iron
What vitamins are stored in the liver
Vit A,D,E and B12
Iron
6 LFTs in routine liver panel
Alkaline phosphatase ALT (alanine aminotransferase) Bilirubin Albumin Total protein GGT (gamma glutamyl transferase)
What would you test to determine the functional production of metabolites?
Urea, plasma proteins
What would you test to measure the clearance of endogenous substances?
Bilirubin
Ammonia
Hormones
What would you test to measure the clearance of exogenous substances?
Drugs, toxins
Measure of the integrity of the hepatocytes- released during damage
Aminotransferases
2 types of aminotransferases
Alamine/ALT
Asparate/AST
Which aminotransferase is more specific for the liver?
ALT
Where else, other than the liver, is AST found?
In the muscle and RBCs
Tumour markers for primary hepatocellular carcinoma (high levels found in children)
alpha fetoprotein
What are the 2 main results of biliary tract damage
Impaired excretory function (increased conjugated bilirubin)
Increased synthesis of enzymes by cells lining the bile canaliculi (ALP and yGT)
When do you get elevevated ALP (alkaline phosphatase)
Due to increased production by cells lining the bile canaliculi and overflow into blood
4 causes of elevated alkaline phosphatase
Cholestasis
Infiltrative diseases
Space-occupying lesions (tumours)
Cirrhosis
Sites of production of ALP
Liver, bone, intestine, placenta
How do you distinguish between ALP isoenzymes
Liver and bone ALP isoenzymes separated by electrophoresis
Enzyme that is elevated due to structural damage, and can support a liver source of raised ALF
Gamma glutamyltransferase (yGT)
When can gamma glutamyltransferase levels be induced?
Alcohol
Enzyme inducing agents e.g. anti-epileptics
Fatty liver e.g. alcohol, diabetes, obesity
Heart failure
Prostatic disease
Pancreatic disease
Kidney damagw
Novel biochemical markers of fibrosis
ELF score (PIIINP, TIMP-1, Hyaluronic acid)
Bilirubin is a measure of what?
Excretory capacity of the liver and free flow of bile
What 3 measurements of bilirubin can be taken?
Total
Unconjugated
Conjugated
What levels of bilirun defines jaundice
> 40micromol/l
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2 examples of pre-hepatic hyperbilirubinaemia
Haemolysis e.g. rhesus incompatibility
Ineffective erythropoiesis e.g. spherocytosis
4 post hepatic (obstructive) causes of jaundice
Gallstones
Bilicary stricutre
Cancer e.g. cholangiocarcinoma
Cholangitis
2 examples of inborn errors of bilirubin metabolism
Decreased activity of UDP glucoronyl transferase
Reduced ability to excrete bilirubin glucuronide
2 inborn errors related to decreased activity of UDP glucuronyl transferase
Gilbert’s
Crigler Najjar
2 inborn errors related to reduced ability to excrete bilirubin glucuronide
Dubin-Johnson
ROTOR
AST/ALT elevated and normal ALP
90% hepatitis
AST/ALT normal and elevated ALP
90% obstructive jaundice
urine results in prehepatic jaundice
No urinary bilirubin
Urine results in post-hepatic obstruction
Dark urine and pale stools
Tests for viral hepititis
Serology (hep A-E, EBV, CMV, HIV)
Tests for chronic active and autoimmune hepatitis
Anti smooth msucle, anti liver/kidney, anti microsomal and anti nuclear antibodies
Test for primary biliary cirrhosis
Anti mitochondrial antibodies
Tests for hereditary haemachromatosis
ferritin, transferrin saturation, liver biopsy, genetic testing
Test for wilson’s disease
Caeruloplasmin, urine copper, plasma copper, liver biopsy
Test for alpha antitrypsin deficiency
Alpha antitrypsin, genetic testing
Test for hepatocellular cancer
AFP
4 effects of oestrogen not being broken down in liver disease
Gynaecomastia
Spider naevi
Liver palms
Testicular atrophy
What percentage of subjects with abnormal LFTs have liver disease?
1%
5 signs/symptoms of liver disease
Pain Itching Jaundice TATT Bruising
Exocrine secretions come from which cells?
Ductal and acinar cells
What 2 exocrine secretions are secreted from the pancreas?
Bicarbonate
Digestive enzymes
Describe the pathology of acute pancreatitis
Acute necrotising liquefaction
Inflammatory
Causes of acute pancreatitis
Gallstones Alcohol Drugs Hypertriglyceridaemia- increased demand on pancreas for digestive enzymes Trauma,infections Rare tumours, autoimmune
Symptoms of acute pancreatitis
Severe epigastric pain
Sudden onset
Radiating to the back
Potential biochemical features of acute pancreatitis
Uraemia Hypoalbuminaemia Hypocalcaemia Hyperglycaemia Metabolic acidosis Abnormal LFTs
Diagnosis for acute pancreatitis
Amylast or lipase
Imaging
Clinical history
Pathology of chronic pancreatitis
Progressive loss of both islet cells and acinar tissues
Presentation of chronic pancreatitis
Abdominal pain
Malabsorption
Impaired glucose tolerance
Alcohol often an important factor
Do amylase/lipase values play a role in the diagnosis of chronic pancreatitis/
No
Diagnosis of chronic pancreatitis
Imaging
Pancreatic function tests for investigating insufficiency
Misc. Vit D, calcium, FBC, LFTs, glucose, lipids
2 types of pancreatic function tests
Direct (invasive) test
Indirect (non-invasive) test
Intubation to collect aspirates in the duodenum.
Secretin, CCK, Lundh Tests
Direct (invasive) tests
Pancreatic enzyme analysis in stools (Elastase)
Trypsinogen (IRT) measured in blood in CF screening
Pancreolauryl & NBT-PABA tests
Indirect (non invasive tests)
