ILA 6 - Jaundice Flashcards
Describe the cycle of bilirubin metabolism
- Erythrocytes are formed from reticulocytes from bone marrow via erythropoiesis
- Erythrocytes combine with haemoglobin to carry oxygen in the blood
- They have a lifespan of around 120 days
- Macrophages in the spleen and bone marrow engulf and degrade old and damaged erythrocytes
- erythrocytes release the haemoglobin which is broken into globin (formed from aminoacids so broken down and recycled) and heme (Fe2+ and unconjugated bilirubin)
- Unconjugated bilirubin is toxic so it needs to be removed, it is yellow/orange in colour
- UCB is lipid soluble and so it must be carried around via albumin to the liver
- The liver has two sources of UCB, this is because Kuffer cells (macrophages of the liver) also breakdown erythrocytes
- In the liver UCB combines with GLUCORONIC acid to form conjugated bilirubin - this is water soluble and is excreted via bile from the liver through the common bile duct into the intestine
- At the ileum and the beginning of the large intestine intestinal bacteria convert CB to UROBILINOGEN by removing GLUCOLROMIC acid
- Urobilinogen is lipid souble
- 10% binds to albumin and is reabsorbed by the liver
- The remaining 90% is oxidised to form STEROCOBILIN (brown) and is excreted in faeces
- Of the other 10% about 5% participates in the entero-hepatic circulation and is excreted into bile again, the other 5% is taken to the kidneys and excreted in urine
Describe the macroscopic anatomy of the liver
Ligaments - falciform, coronary, ligamentum teres, R and L triangular ligaments
Lobes - R (caudate and quadrate), L
Describe the microscopic anatomy of the liver
Hepatocytes (stain pink) - thin plates seperated by sinusoids
- VAD hepatic portal vein, hepatic artery, bile duct
Describe the anatomical regions of the abdomen
R and L hypochrondriac
R and L lumbar
R and L iliac
epigastric, umbilicus, hypogastric
How can jaundice be classified?
- Pre hepatic, increased haemolysis (increased RBC breakdown so increased levels of bilirubin)
- Intracellular, function of the liver is compromised, damage due to infection, alcohol
- Post hepatic, when the bile-duct system is compromised (damaged, inflamed, obstructed), this means that the gall bladder cannot move bile into the digestive system = causes build up of bilirubin in the liver
Give 2 examples of causes for each of the following; pre-hepatic, post hepatic and intrahepatic jaundice
Pre-hepatic = increased haemolysis, Malaria (targets RBCs, malaria’s rapid multiplication destroys RBCs and releases more parasites = feedback loop), Sickle-cell (RBCs have shorter life span, so increased bilirubin)
where? spleen/blood/periphery
Post-hepatic = gall stones/cancer (can block common bile duct), pancreatic cancer, pancreatitis (both can compress common bile duct)
where? biliary tract
Intracellular = infection or alcohol, compromises liver’s ability to process bilirubin (hep a,b, c, alcoholic liver disease -cirrhosis, glandular fever, gilbert’s syndrome, drug misuse, autoimmune)
where? the liver/hepatocytes
What symptoms are associated with jaundice?
- yellow eyes and skin
- itchiness
- fatigue
- weight loss
- vomiting
- blood clotting
- fever
What symptoms are associated with post/pre hepatic or intracellular jaundice?
Pre-hepatic
a) increased unconjugated bilirubin (so jaundiced), increased CB and urobilinogen
b) normal LFTs
c) normal stools
d) normal urine
e) splenomegaly (increased size of spleen)
Post hepatic, increased conjugated bilirubin cannot make it to small intestine from liver
a) dark urine (less yellow urobilinogen in urine)
b) pale stools (less brown sterobilin)
c) no splenomagaly
d) normal LFTs
e) may have abdomen pain due to obstruction
Hepatic, liver disease, problem transporting from blood to bilary canaliculi, and problems conjugating
a) increased UCB
b) increased CB
c) normal/pale stools (less brown sterobilin gets to urine)
d) dark urine (less yellow urobilinogen in urine)
e) splenomegaly (increased to cope)
f) deranged LFT
