Jaundice Flashcards
What is Jaundice?
due to excessive accumulation of bilirubin in tissues
What are the three metabolism of bilirubin?
- Production of unconjugated bilirubin
- Conjugation of bilirubin
- Excretion of bilirubin
Where are rbc broken down and why?
in the spleen by macrophages
How is unconjugated bilirubin made?
- rbc broken down by macrophage in spleen
2. degrade into hb into iron and unconjugated bilirubin
Where is the iron stored and the unconjugated bilirubin taken?
- Iron stored inside trasnferrin proteins
2. Unconjugated bilirubin travels to liver and binds to albumin
Is unconjugated bilirubin insoluble?
yes
In disease where can unconjugated bilirubin be produce?
by haemolysis of rbc outside of spleen
How is bilirubin conjugated?
- Liver hepatocytes uptake unconjugated bilirubin
2. Gets conjugated to glucuronate
Is conjugated bilirubin soluble?
yes
Once bilirubin is conjugated where is it secreted into?
bile canaliculi
Where does the bilirubin flow?
with the bile down bile ducts into duodenum
How is conjugated bilirubin metabolized?
by bacteria into colourless products
Why is feaces brown?
- reabsorbed by the gut and excreted by kidney but most oxidized in gut into coloured pigement which give faeces brown colour
- If complete obstruction of bile ducts, no flow of CB, no conversion so no urobilinogen in urine
What is prehepatic jaundice?
caused by excess production of bilirubin
What is hepatic jaundice?
due to pathology of liver (hepatocytes and bile canliculi) (e.g. Hepatitis and PCS)
What is post-hepatic jaundice?
problem with biliary flow
What is obstructive jaundice?
cause by lack of bile flow into gut
How does obstructive jaundice manifest?
pale faeces + dark urine
What is cholestatic jaundice?
caused by bilirubin not flowing out via CBD
What can cholestatic jaundice be caused by?
- obstruction e.g. gallstone
2. paralysis (ileus) of the cbd peristalisis e.g. drug induced
What is unconjugated jaundice?
caused by accumulation of unconjugated bilirubin
What causes unconjugated jaundice?
- excessive production of unconjugated bilirubin
2. due to decresed capacity to conjugate bilirubin
What is conjugated jaundice?
accumulation of conjugated jaundice
What types of jaundice are conjugated jaundice?
Post hepatic jaundice is always conjugated but hepatic jaundice can be conjugated or unconjugated
What are the differential diagnosis of increased production of bilirubin jaundice?
- Intravascular haemolysis
- Extravascular haemolysis
What does intravascular haemolysis manifest as?
- black urine due to free haemoglobin being degraded via an alternative pathway into haemosiderin
- shcistocytes on a blood film
What are the congenital causes of intravascular haemolysis?
- G6PDH deficiency
- PK deficiency
- sickle cell disease
- thalassaemia
What are the acquired causes of intravascular haemolysis?
- artifical heart valves
- blood group mismatch
- DIC
- malaria,
- HELLP syndrome in pregnant women
How does extravascular haemolysis present?
if the increased haemolysis is taking place in the spleen:
- splenomegaly
- spherocytes on blood film
What are the congenital causes of extravascular haemolysis?
hereditary spherocytosis
What are the acquired causes of extravascular haemolysis?
autoimmune haemolysis
Why might there be decreased conjugation of bilirubin?
- not enough unconjugated bilirubin getting into the hepatocytes for conjugation (reduced hepatocyte uptake)
- hepatocytes are not conjugating bilirubin adequately (enzymatic problems)
What are the reasons for reduced hepatocyte uptake?
- cholecystographic contrast agents
2. portosystemic shunts to bypass cirrhotic liver
What are the possible congenital enzymatic problems?
- Gilbert’s syndrome
2. Crigler-Naj-Jar syndrom3
Why might there be decreased excretion of bilirubin?
- Can’t make it out of damaged hepatocytes
2. Can’t make to bowel due to obstruction
What are the manifestations of decreased excretion of bilirubin?
- Feaces become pale due to lack of stercobilin, steatorrhea
- Urine become dark (due to conjugated bilirubin which is water soluble)
What are the infective reasons for decreased excretion of bilirubin?
- Viral hepatitis
- Bacterial hepatitis
- Ascending cholangitis
- Liver abscess
- Tapeowrm infection
What are the neoplastic reasons for decreased excretion of bilirubin?
- Metastatic liver cancer
- Hepatocellular carcinoma
- Pancreatic cancer
- Cholangiocarcinoma
What are the vascular reasons for decreased excretion of bilirubin?
Budd-Chaiari syndrome (thrombosis in hepatic vein)
What are the inflammatory reasons for decreased excretion of bilirubin?
- Primary biliary cirrhosis (PBC)
- PSC
- Autoimmune hepatitis
- Pancreatitis
What are the trauma reasons for decreased excretion of bilirubin?
- Gallstones
2. Stricture (after ERCP)
What are the endocrine reasons for decreased excretion of bilirubin?
Intrahepatic cholesatsis of pregnancy
What are the metabolic reasons for decreased excretion of bilirubin?
- Wilson’s disease
2. Haemochromatosis
What are the drug reasons for decreased excretion of bilirubin?
- Paracetemol overdose, valproate, rifampicin, alcohol abus: affect ability of hepatocytes to excrete bilirubin
- Co-amoxiclav, nitrodirantoin, OCP can induce paralysis of the biliary system
What personal information is important to gather in history of jaundice?
Ethnic background
Why is ethnic background important in jaundice?
- sickle cell disease affect West African and afro-caribbean patients
- thalassaemia and G6PDH deficiency affect mediterranean, East Asian and African patients
What must you ask about the presenting complaint with jaundice?
- Acute or chronic
- Pregnant
What conditions in pregnancy can give jaundice?
- intrahepatic cholestasis of pregnancy
- pre-eclampsia with HELLP syndrome
- acute fatty liver of pregnancy
What associated symptoms should you ask about?
- RUQ discomfort, nausea, vomiting and pruritis
- Fever and diarrhoea
- Steatorrhoea, dark urine, pruritus
- Weight loss, fever, night sweats
- Bronzed skins, signs of DM
- Exposure to outdoor water / sewage
