Jaundice (oxford clin cases) Flashcards
What causes jaundice?
A build up of bilirubin in tissues
Where are RBCs broken down?
Spleen mainly
What breaks down RBCs
Macrophages
What are RBCs broken down into? (and what part of the RBC is broken down to give these products?)
Heamoglobin is broken down into:
Unconjugated bilirubin
Iron
How does unconjugated bilirubin circulate?
Bound to albumin
Where does unconjugated bilirubin go?
From the spleen to the liver
What happens to unconjugated bilirubin in the liver?
It is conjugated
What is conjugated bilirubin called? What are its characteristics?
Glucuronate, it is water soluble
Where is bilirubin secreted into from the liver?
Bile cancliculi (duct)
What happens to bilirubin in the gut?
It is metabolized by bacteria into urobilinogen and stercobilinogen which give faeces their colour
What will happen to urine if there is complete obstruction of the bile duct?
There will be no trace of urobilinogen in the urine
What are the 3 ways bilirubin can cause jaundice?
Problems with bilirubin production
Problems with bilirubin conjugation
Problems with bilirubin excretion
What is prehepatic jaundice?
Jaundice due to excess bilirubin production eg increased breakdown of RBC in vessels or spleen
What is hepatic jaundice?
Jaundice due to failures in the liver eg reduced uptake by hepatocytes, reduced conjugation of bilirubin by enzymes or damage to hepatocytes
What is post hepatic jaundice?
Problems with bile flow
What is obstructive jaundice?
Jaundice due to lack of bile flow into the gut
What will faeces and urine look like in obstructive jaundice?
Faeces will be pale due to lack of sterco/uro bilinogen amd urine will be dark in colour due to conjugated bilirubin in them
What is cholestatic jaundice?
Jaundice due to bilirubin not flowing out of the common bile duct
What are the 2 types of haemolysis?
Intra and extra vascular
What will intravascular haemolysis present with? Explain why
Dark urine due to free haemoglobin being excreted
What are congenital causes of intravascular haemolysis?
G6PDH deficiency
PK deficiency
Sickle cell
Thalassaemia
What are accquired causes of intravascular haemolysis?
Heart valve replacement Blood transfusion mismatch DIC Malaria Medication HELPP syndrome in pregnant women
What are congenital causes of extravascular haemolysis
Hereditary spherocytosis
What are acquired causes of extravascular haemolysis
Autoimmune spherocytosis
What will be seen on blood film in someone with intravascular haemolysis?
Schistocytes (fragmented blood cells)
What will be seen on blood film in someone with extravascular haemolysis?
Spherocytes
What are some congenital enzyme problems that may reduce conjugation of bulirubin
Gilbert’s syndrome (common)
Crigler-Naj-jar syndrome (rare)
What acronym is used to remember acquired cuases of decreased bilirubin excretion?
INVITED MD Infection- viral/bacterial hepatitis etc Neoplasia- tumors of the liver, pancreas, bile duct Vascular- budd chiari syndrome (thrombosis in the hepatic vein) Inflammation Trauma- gallstones, stricture Endocrine- due to hormones in pregnancy Degenerative Metabolic Drugs
What symptoms alongside jaundice would steer you towards a diagnosis of hepatits?
Right upper quadrant pain
Itching
Nausea and vomitting
What does fever and diarhoea alongside jaundice make you think could be the cause?
Infection of the liver
What symptoms alongside jaundice would you suspect if there is an obstruction to bile outflow?
Steatorrhea
Dark urine
Itching
What symptoms alongside jaundice would you suspect if they have haemochromatosis?
Bronzed skin and diabetes mellitus signs
What are the 4 mechanisms by which medications can cause haemolysis?
Intravascular haemolysis
Extravascular haemolysis
Cholestasis
Hepatitis
What should you ask about/ look for in past medical history when a patient has jaundice?
History of gallstones Pregnancy Medication they're on Liver disease (infection, alcohol) Haemophilia Recent blood transfusion Ulcerative colitis Emphysema Psychosis
What should you ask about/look for in family history when a patient has jaundice?
Wilson's Gilbert's syndrome Haemophilia Sickle cell Thalassaemia
What should you ask about/look for in social history when a patient has jaundice?
IV drug use Unprotected sex/multiple partners Foreign travel Alcohol consumption Tattoos
What is meant when a patient is described as jaundiced?
They have yellow skin
What is the medical name for yellow eyes?
Icteric
What may be seen on inspection when a patient has chronic liver disease?
Spider naevi Palmar erythema Clubbing Bruising Gynaecomastia
What is seen in the eyes that indicates Wilson’s disease?
Green rings (kayser-fleischer)
What does right upper quadrant tenderness suggest when a patient has jaundice?
Hepatitis
Gallbladder disease
When should you do a blood film to investigate jaundice?
If FBC shows anaemia
If serum unconjugated bilirubin is raised
When should you do viral serology/ASMA/ANA to investigate jaundice?
If liver enzymes are raised
When should you do ultrasound of the biliary tree if the patient has jaundice?
Raised gallbladder enzymes
Positive urine bilirubin
Positive serum amylase
What are the 2 main liver enzymes vs 2 main gallbladder enzymes?
Liver= ALT, AST Gallbladder= ALP, GGT
What investigation should be done if you suspect hepatocyte damage and what will results be?
Check liver enzymes, they will be raised
What does AST>ALT suggest?
Excessive alcohol intake
What does ALT>AST suggest?
Viral hepatitis
What are causes of AST/ALT in the thousands?
Viral hep
Paracetamol overdose
Ischaemic hep
What will serum bilirubin be if the problem is obstruction of bile flow? Why?
Conjugated bilirubin >20% of total bilirubin because this shows the liver is conjugating the bilirubin that goes through it
Where is ALP released from?
Damaged biliary epithelial cells and the placenta
Where is GGT released from?
Biliary epithelial cells
What does high ALP and high GGT suggest?
Bile duct pathology
Could also be hepatitis
What does high ALP but normal GGT suggest?
High bone turnover (mets in bone or hyperparathyroidsm) or pregnancy
What does high GGT alone suggest?
Recent alcohol consumption
What type of jaundice manifests as dark urine?
Posthepatic jaundice
What does bilirubin in the urine suggest?
Posthepatic obstruction- the bilirubin has to be excreted via an alternate route
Why is there no urobilinogen in the urine of patients with posthepatic jaundice?
Because bilirubin cannot reach the gut so it isn’t broken down into urobilinogen and excreted in the urine
What might you look at in investigations if you suspect jaundice is due to haemolysis?
Haptoglobins- will be depleted
Lactate dehydrogenase- will be raised
Direct antiglobulin test (DAT)- if you suspect haemolysis
Blood film
What disease increases risk of PSC?
Ulcerative colitis
