Jaundice And Lfts Flashcards
Define jaundice
Clinical manifestation of raised bilirubin
Hyperbilirubinaemia
What are the clinical eateries of jaundice
Yellow discolouration. Eg in sclera of eye, skin. Can be quite hard to detect in skin.
Look for other signs of liver disease. Hepatomegaly? Portal hypertension? Ascites varices? Splenomegaly - backlog can cause enlargement of the spleen/
What is bilirubin
Bilirubin Breakdown product of haem ◦ Unconjugated state bound to albumin Conjugated in the liver ◦ Water soluble Excreted in urine and faeces It
How can the causes of jaundice be categorised
PRE-HEPATIC Too much haem HEPATIC Reduced hepatocyte function POST-HEPATIC Obstructive causes
What is pre hepatic jaundice
Caused by increased degradation of haemoglobin
◦ Liver conjugating ability is fine
◦ Excretion pathway is fine
Too much demand on the liver Therefore, the levels of bilirubin that are raised tend to be unconjugated
Harm broken down into bilirubin . Building up too much haem - cant be processed by liver bc too mcuh demand on it.
What are common causes of pre-hepatic jaundice
Haemoglobinopathies ◦ Sickle cell ◦ Thalassaemia ◦ Spherocytosis Damage to red blood cells ◦ Haemolysis
Why can newborns get jaundice1
Newborns can develop jauncie bc liver is immature - normal physiologically - can be jaundiced for first day or so of lie. Unconjugated bilirubin can cross the BBB and cause alterations in brain
Describe hepatic jaundice
This is caused by reduced conjugating ability of the liver
◦ Damage to hepatocytes
◦ Amount of bilirubin is fine
◦ Excretion pathway is usually fine
Therefore, you get a mixed picture of conjugated and unconjugated bilirubin
Some of the liver can conjugate, other areas are damaged. Duct system - inflammation and compression can occur. Both conjugated nd unconjugated
What are causes of hepatic jaundice
Chronic Cirrhosis - (hallmark featur = hepatocyte necrosis) — Hepatitis B or C (viral hep) — autoimmune hepatitis — alcoholic liver disease — some long term medications eg methotrexate can cause hepatocyte damage — hereditary haemochromatosis — Wilson’s disease
Acute Also bear in mind that jaundice can occur in acute liver damage ◦ Paracetamol toxicity ◦ Viral hepatitis ◦ Other infections
Describe post hepatic jaundice
This is caused by obstruction to the excretion pathway
◦ Amount of bilirubin is fine
◦ Conjugating ability of the liver is fine Therefore, the raised bilirubin tends to be conjugated
Bilirubin cant enter GI tract easily bc obstruction - goes down other athwart.
Descrbe teh biliary tree anatomy
Cystic duct - acute choecystitis
Common bile duct stones - ascending cholangitis?
Stone blocking ampulla of vaster can cause pancreatitis ss
What is a key symptom of post hepatic jaundice
NOTE: Bilirubin is pigmented Conjugated bilirubin is water soluble More is going to be excreted by the kidneys
Therefore, pathologically high levels of conjugated bilirubin can lead to dark urine and pale stools
Needs to be water soluble so. T can be excreted thru gut or absorbed into blood and then excretedd by kidney
If there is an obstruction to gut - more goes to kidney - pigment more in urine less in stools.- shunt of bilirubin to kidney rather than gut
What are common causes of post hepatic jaundice
Gallstones Any intrahepatic pathology compressing the bile ducts
◦ PBC
◦ PSC
◦ Malignancy Biliary stricture
Pathology of the head of the pancreas eg malignancy Can compress biliary tree and cause obstruction
Painless jaundice
What are LFTs
Bilirubin ◦ Conjugated vs unconjugated Albumin Alanine transaminase (ALT) Aspartate aminotransferase (AST) Alkaline phosphatase (ALP) LFTS - assesses enzymes that have been released due to damage.
Wat is abumin
Major serum protein
This assesses synthetic function of the liver
◦ i.e. if liver function is reduced, it makes less albumin
◦ Usually seen in chronic cases
Low albumin contributes to ascites
Link to urinary
◦ Low levels of albumin - Lowe protein in urine eg due to nephrotic syndrome
Other proteins made by the liver can also be measured to assess its synthetic function
Clotting can be measured - inr - but this is not included in an left
