Flashcards in Diseases of the liver and pancreas Deck (49)
Which organelle conjugates bilirubin?
Smooth endoplasmic reticulum
What are the functions of the liver?
- Glycogen storage & synthesis
- Glycolysis & gluconeogenesis
- Synthesis & catabolism
- Clotting factors
- Amino acid metabolism &urea synthesis
- Lipoprotein & cholesterol synthesis
- Fatty acid metabolism
- Bile acid synthesis
Excretion & detoxification
- Bile acid & bilirubin excretion
- Drug detoxification & excretion
- Steroid hormone inactivation & excretion
- Iron storage
- Vitamin A, D, E & B12 storage & metabolism
What is measured by LFTs?
ALT (alanine aminotransferase)
AST (aspartate transaminase)
GGT (glutamyl transferase)
What tests might be used for specific liver functions?
- prothrombin (clotting factors)
- bile acids
Excretion and detoxification
- steroid hormones
- Ferritin (iron storage)
- Prothrombin time (Vit K)
What tests give an indication of hepatocyte damage?
- Found in the cell and only released by cellular damage.
ALT is more specific for liver than AST
AST also found in muscle and red blood cells
Tumour markers – α-fetoprotein (primary hepatocellular carcinoma)
What tests give an indication of biliary tract damage?
Impaired excretory function
- Increased Conjugated bilirubin
Increased synthesis of enzymes by cells lining the bile canaliculi
What might be the causes of increased ALP in biliary tract damage?
Cholestasis (intra- or extrahepatic)
Space-occupying lesions (tumours)
Which organs also secrete ALP isoenzymes?
If γGT and ALP are raised, what might this mean?
A raised γGT supports a liver source of ALP (as opposed to any other isoenzyme).
Elevated due to structural damage
What can cause biliary tract damage?
enzyme inducing agents
- e.g. anti-epileptics
- e.g. due to alcohol, diabetes or obesity
- acute & chronic pancreatitis, cancer
- ARF, nephrotic syndrome, rejection
What are the biochemical markers of fibrosis?
- Hyaluronic acid
What is bilibrubin a measure of?
Excretory capacity of the liver and free flow of bile.
What is bilirubin measured as?
- Pre-hepatic & Hepatic
- Post-hepatic (Obstructive) & Hepatic
What serum level of bilirubin is considered to be jaundice?
> 40-50 μmol/L
What happens to bilirubin in the liver?
It is conjugated to bilirubin glucuronide by glucuronyl transferase.
What protein is bilirubin bound to in the blood?
What are the pre-hepatic causes of jaundice?
- e.g. Rhesus incompatibility
- e.g. spherocytosis
What are the post-hepatic (obstructive) causes of jaundice?
- i.e. cholangiocarcinoma, head of pancreas
What are the hepatic causes of jaundice?
- Inherited disorders of conjugation e.g. Gilberts, Crigler-Najjar
- Post-microsomal/impaired excretion
- Intrahepatic obstruction
- Inherited disorders of excretion e.g. Dubin-Johnson, Rotor.
What are the inborn errors of bilirubin metabolism?
Decreased activity of UDP glucuronyl transferase
Reduced ability to excrete bilirubin glucuronide
What is the pathway from haemoglobin to bilirubin glucuronide?
Haemoglobin -> bilirubin albumin-bound bilirubin -> bilirubin -> bilirubin glucuronide -> bile duct
The patient is jaundiced, their AST/ALT is elevated and their ALP is normal. What will are they likely to have?
Approx 90% of these patients will have hepatitis
The patient is jaundiced, their AST/ALT is normal and their ALP is elevated. What will are they likely to have?
Approx 90% will have obstructive jaundice
What will urine tests show in prehepatic jaundice?
Unconjugated bilirubin - no urinary bilirubin
What will urine tests show in hepatic jaundice?
Variable depending on degree of obstruction due to either disease or inflammatory oedema
What will urine tests show in post-hepatic jaundice?
Dark urine (&pale stools)
What are the systemic effects of liver disease?
- spider naevi
- liver palms
- testicular atrophy
osteomalacia / osteoporosis
What specific tests can be used in chronic active and autoimmune hepatitis?
Anti smooth muscle, anti liver/kidney, anti microsomal and anti nuclear antibodies
What test can be used for primary biliary cirrhosis?
Anti mitochondrial antibodies
What test can be used for hereditary haemachromatosis?
What tests can be used to detect Wilson's disease?
Are routine LFTs useful?
No - only 1% of people with abnormal LFTs have liver disease
What should LFTs be measured?
Signs and symptoms ?
- recent travel
- drug use
Is liver disease present ?
- liver cancer,
What is the severity ?
- chronic hepatitis vs acute onset
How does the pancreas drain?
Drains via main pancreatic duct joined to the common bile duct.
Opens into duodenum via Sphincter of Oddi.
What part of the pancreas produces endocrine secretions?
Islets of Langerhans
What are the endocrine secretions of the pancreas?
What part of the pancreas produces exocrine secretions?
Ductal and acinar cells
What are the exocrine secretions of the pancreas?
- Trypsin, Chymotrypsin & Elastase
What is acute pancreatitis?
Acute necrotising liquefaction
What is the aetiology of acute pancreatitis?
Rare tumours, autoimmune, Scorpion Toxins!
What are the symptoms of acute pancreatitis?
Severe epigastric pain
Radiating to the back
What are the potential biochemical features of acute pancreatitis?
What tests might be used in the diagnosis of acute pancreatitis?
Amylase or Lipase
What is chronic pancreatitis?
Progressive loss of both islet cells and acinar tissue.
What is the presentation of chronic pancreatitis?
- often presenting feature
Impaired glucose tolerance
Alcohol often an important factor
Are tests of exocrine function of any use in chronic pancreatitis?
No - only in acute exacerbations
How does one perform the diagnosis and management of chronic pancreatitis?
Pancreatic Function test for investigating insufficiency
- Vitamin D
What are direct (invasive) tests of pancreatic function?
Intubation to collect aspirates in the duodenum.
Secretin, CCK, Lundh Tests