Jaundice Flashcards
what is jaundice
yellow discolouration of the skin, sclera and mucous membranes
due to the deposition of bilirubin in the tissues
when does jaundice occur
it develops when serum bilirubin levels are elevated about 34mmol/L
normal level of serum bilirubin
5-17mmol/L
where is jaundice seen on the body
bilirubin has a high affinity for elastin
jaundice is detected earliest in tissues with high elastin eg. sclera
bilirubin is a waste product of
the breakdown of team from red blood cells
how is bilirubin transported
transported by albumin because it is water insoluble (unconjugated bilirubin)
how is bilirubin taken up by the liver
taken up passively into hepatic cytoplasm with some active uptake as well
inefficient process
what happens to bilirubin in the liver cytoplasm
conjugated to bilirubin glucuronosides (conjugated bilirubin)
this is water soluble
how does conjugated bilirubin leave the liver
excreted actively against the gradient by energy dependant transporters
what happens to conjugated bilirubin after leaving the liver
may diffuse back into hepatic sinusoids passively
majority will be excreted into bile and then into small intestine
how does bilirubin leave the body
in the terminal ileum and the colon, bacteria remove the glucuronic acid
bilirubin becomes unconjugated again and is called urobilinogen
what happens to urobilinogen
further oxidation by bacteria to form stercobilin and is released in faeces
bilirubinuria
conjugated bilirubin being excreted in urine
why can’t unconjugated bilirubin be excreted in urine?
it is fat soluble and water insoluble therefore doesn’t dissolve in urine
is the presence of bilirubin in urine normal?
no
it is a marker of conjugated hyperbilirubinaemia
can be an early sign of hepatic or biliary disease
what may the urine of a patient with conjugated hyperbilirubinaemia look like
tea or cola coloured urine
what may the urine of someone with unconjugated hyperbilirubinaemia look like
normal
describe two reasons someone may be jaundiced
- they are producing more bilirubin than the liver can process
- they are unable to excrete bilirubin and it is accumulating
why might you not be able to excrete bilirubin?
- you can’t conjugate it due to enzyme dysfunction (either ineffective or lack or enzyme, or due to unhealthy hepatocytes)
- you can’t excrete the bilirubin either due to ineffective transport out of hepatocytes or obstruction of biliary system
what is the cause of being unable to conjugate bilirubin enzymatically?
caused by ineffective or lack of enzymes, which is usually a genetic issue
Crigler-Najjar syndrome type 1 is life threatening due to almost complete lack of activity
Crigler-Najjar syndrome type 2 causes significant reduction in activity
what happens when you can’t conjugate bilirubin enzymatically
predominantly unconjugated jaundice
why does hepatocyte damage cause jaundice?
come conjugation occurs but bilirubin leaks out of cytoplasm due to cell damage
usually inflammatory issue or related to infection
progressive damage will deplete functioning enzymes and ultimately no conjugation will occur
what kind of jaundice does hepatocelular damage cause?
both conjugated and unconjugated
what kind of jaundice does ineffective or lack of enzymes cause?
predominantly unconjugated
why might you not be able to transport bilirubin out of hepatocytes
a problem with transporters which is genetic
eg.
Dublin-johnson syndrome
rotor syndrome
what happens when you can’t transport bilirubin out of hepatocytes
conjugated bilirubin accumulates causing jaundice with conjugated bilirubin
why might you be unable to excrete bilirubin into the intestine
obstruction of biliary system
must affect a large portion of liver drainage to be a problem
what type of jaundice to you get when the biliary system is obstructed
predominantly unconjugated
jaundice in neonate
can accumulate and cause brain damage
kernicterus
what is the type of brain damage caused to neonates due to accumulation of bilirubin in blood
kernicterus
jaundice with abdominal pain
stone
jaundice with high temp
infection
jaundice with weight loss
cancer
jaundice with bleeding
coagulopathy
jaundice with ascites
liver failure
jaundice and low blood pressure
sepsis
jaundice and portal hypertension
cirrhosis
jaundice and itching
obstructive jaundice
jaundice with fatigue
haemolytic anaemia
4 most common causes of jaundice
gallstone
infectious hepatitis
carcinoma head of pancreas
haemolytic anaemia
additional symptoms in gallstones
episodic indigestion
flatulent dyspepsia
pruritus
additional symptoms in infectious hepatitis
anorexia, nausea, malaise
additional symptoms in cancer in head of pancreas
anorexia, weight loss, pruritus
additional symptoms in haemolytic jaundice
general malaise, dyspnoea, weight loss
Charcot’s triad
RUQ pain
jaundice
fever
raynold’s pentad
RUQ pain
jaundice
fever
hypotension
altered mental status
Courvoisier’s sign/law
enlarged, non tender, and palpable gallbladder in patients with obstructive jaundice due to tumours of the biliary tree or pancreatic head
Murphy’s sign
positive if patient experiences RUQ tenderness and stops breathing upon inspiration as the gallbladder moves down in contact with the examiner’s hand
suggestive of acute cholecystitis
pre hepatic cause of jaundice
excessive haemolysis leading to increased bilirubin delivered to the liver
intrahpetic cause of jaundice
defective conjugation
impaired cellular uptake
abnormal secretion
post hepatic causes of jaundice
mechanical obstruction of bile flow causing impaired secretion
nature of pre hepatic jaundice
unconjugated
normal urine and stool colour
no pruritus
nature of intrahepatic jaundice
unconjugated and conjugated
dark urine
normal stool
no pruritus
nature of post hepatic jaundice
conjugated
dark urine
acholic faeces
pruritus
what to look for on FBC
anaemia (haemolysis and chronic disease)
infection (high WCC)
platelet function (low in cirrhosis)
what to look for on U&Es
assess renal and electrolyte status
severe sepsis can damage kidney
what to check for with lipase
assess associated pancreas obstruction
what to look for with CRP
indicated inflammation and complication of inflammation (but has delayed response)
extra hepatic cholestasis
in the duct: stones/ foreign bodies / parasites
in the wall: atresia/ traumatic stricture/ tumour/ PSC
outside the duct: 1° or 2° tumour/pancreatitis
benign causes of extra hepatic cholestasis
choledocholithiasis
mitizzi syndrome
bile duct stricture
chronic pancreatitis
primary sclerosing cholangitis
choledochal cyst
ischaemic strictures
malignant causes of extra hepatic cholestasis
pancreatic cancer or ampullarf cancer
bile duct cancer (cholangiocarcinoma)
using ultrasound to image cholestasis
assess for signs of obstruction (dilatation of biliary tree and at what level)
assess for gall stones in gall bladder or bile duct
assess liver parenchyma for massess, oedema, contour
measure fibroids (sign of cirrhosis)
endoscopic ultrasound for imaging cholestasis
allows for a closer view of the ampulla, bile duct and pancreas
can contain biopsies via core needle
abdo CT scan to investigate cholestasis
good resolution
helps assess anatomy and level of obstruction
may not always seen stones as they are radiopaque (cholesterol)
very good for staging cancer
needs contrast and had radiation hazard to patient
cholangiogram is used for
assessing anatomy of bile duct and look for obstruction and cause
ERCP
side viewing endoscope passed into duodenum to view ampulla of Vater
cannula is placed through ampulla of Vater
contrast injected and x-rays taken to evaluate latency of the ducts
a stone can be retrieved after incising the sphincter
sometimes a stent can be placed to bypass the obstruction to allow bile drainage
