Jaundice Flashcards
What is Jaundice?
The clinical manifestation of elevated plasma levels of bilirubin presenting with yellow tinged skin and sclera
What is bilirubin?
Metabolic breakdown product of haemoglobin (RBCs))
Where does bilirubin metabolism/Hb metbolism begin?
Spleen
Describe the process of bilirubin metabolism:
RBC goes to spleen
Hb broken down into Haem and Globin
Haem further broken down into Biliverdin
Biliverdin converted into UNCONJUGATED bilirubin
This travels to the liver to be conjugated
Conjugated bilirubin oxidised to stercobilin in the duodenum
Conjugated bilirubin becomes urobilinogen in the kidneys
What does stercobilin contribute to the faeces?
The brown pigment
What gives the yellow colour in the urine?
The breakdown product of urobilinogen urobilin
What plasma protein carries unconjugated bilirubin to the liver for conjugation?
Albumin
What amino acid is uncojugated bilirubin conjugated with making it water soluble for excretion?
Glucuronic acid
What are the 3 different types of Jaundice?
Pre-hepatic jaundice
Hepatic jaundice
Post-hepatic jaundice
What is Pre-hepatic jaundice?
Also called haemolytic jaundice
It’s when theres an increased amount of Hb being broken down (haemolysis)
What is the mechanism by which pre-hepatic jaundice causes jaundice?
What type of bilirubin levels are elevated as a result?
Inc haemolysis or RBCs
Overwhelms livers ability to conjugate bilirubin
INC levels of UNCONJUGATED bilirubin in bloodstream
Livers function is still perfectly intact (can still conjugate) its just overwhelmed by too much bilirubin
What can cause Pre-hepatic jaundice?
-Haemolytic anaemias (sickle cell anemia, thalassemia)
-Hereditary conditions affecting RBC strucutre/function (hereditary Spherocytosis)
-meds or toxins causing haemolysis
-infections (malaria)
-blood transfusion reactions
What is the key indicator that a patient has a pre-hepatic jaundice?
Elevated levels of UNCONJUGATED Bilirubin in blood
What is hepatic jaundice?
When the jaundice is caused by reduced hepatic function
Leads to reduced ability to conjugate bilirubin
What can cause Hepatic Jaundice?
Acute and chronic liver diseases
Acute viral hepatitis
Paracetamol toxicity
Certain infections affecting liver
Chronic liver diseases such as cirrhosis
What is the key indicator that a patient has hepatic jaundice?
Elevated levels of CONJUGATED and UNCONJUGATED bilirubin
What is Post-hepatic jaundice?
/obstructive jaundice when theres an obstruction in the bile ducts preventing normal flow of bile from liver to intestines
What levels of bilirubin are high in the blood with post-hepatic jaundice?
CONJUGATED bilirubin
Blockage happens after the liver
What can cause post-hepatic jaundice?
Gallstones
Inflammation or scarring of bile ducts (primary sclerosing cholangitis)
Pancreatic tumours compressing biliary tree
Biliary atresia
What are the key presentations of a patient with post-hepatic jaundice?
Elevated CONJUGATED BILIRUBIN
Pale faeces and Dark Urine
Abdominal pain if gallstones cause
Why are the faces pale and the urine dark in post-hepatic jaundice?
Levels of conjugatde bilirubin are high
They are unable to progress through the biliary tree into the small intestine so the conjugated bilirubin is absorbed back in the blood where it gets filtered by the kidney so levels of conjugated bilirubin are high in the urine
Why is a painless post hepatic jaundice worrying?
Could be pancreatic carcinoma compressing duct
How can cirrhosis cause post-hepatic jaundice?
Non expansive liver causes portal hypertension
This can compress bileduct
