Gi Week 4 Objective 5

Front 1

The causes of jaundice can be classified into 3 main categories, what are they?

Back 1

pre-hepatic, hepatic, post-hepatic (obstructive)

Front 2

True/False. Pre-hepatic jaundice causes conjugated bilirubinemia.

Back 2

false. It causes unconjugated bilirubinemia

Front 3

List some causes of pre-hepatic jaundice.

Back 3

- overproduction – hemolysis, extravasation, shunt hyperbilirubinemia
- reduced uptake – drugs, Gilbert’s syndrome, portosystemic shunt
- conjugation defect – acquired (neonatal, wilson’s disease, hyperthyroidism, chronic persistent hepatitis); inherited (Gilbert’s syndrome, Crigler-Najjar)

Front 4

What is the mechanism leading to jaundice from hemolysis?

Back 4

excessive breakdown of haemoglobin occurring in the reticuloendothelial cells of the spleen, bone marrow, and liver and the kidneys. These phagocytic mononuclear cells are rich in heme oxygenase and biliverdin reductase activities and rapidly degrade heme to bilirubin.

Front 5

Can you measure unconjugated bilirubin in the blood?

Back 5

No. Unconjugated bilirubin is an indirect bilirubin measurement obtained from total bilirubin and direct (conjugated) bilirubin. Note: some labs will give their results and total and direct, others with give the results as total and conjugated.

Front 6

Does hepatitis result in conjugated or unconjugated hyperbilirubinemia, or both?

Back 6

It is predominantly conjugated hyperbilirubinemia due to a problem with impaired hepatic excretion

Front 7

How does viral or drug induced hepatitis lead to jaundice?

Back 7

Hepatitis causes inflammation of the liver cells and eventually necrosis which inhibits hepatic excretion leading to the accumulation of predominantly conjugated bilirubin.

Front 8

Can drug induced hepatitis occur other than by overdose?

Back 8

Yes. Certain medications have risks of hepatitis even at normal recommended doses (ie. methotrexate, acutaine, etc).

Front 9

How can drug-induced hepatitis present if bile duct injury results?

Back 9

It can mimic extrahepatic biliary obstruction, primary biliary cirrhosis, and sclerosing cholangitis, among others therefore it is imperative in every patient with cholestasis to investigate past medication history including prescribed and over the counter drugs.

Front 10

What is a complication of drug induced hepatitis and which class of jaundice might it present as? (pre-hepatic, hepatic, or post hepatic)

Back 10

Cholestatic hepatitis is a complication that can result from excretion impairment in the canaliculus or bile ducts and present predominantly as a post hepatic jaundice.

Hint 10

remember from the pathology lab that toxins generally effect a certain zone within the hepatic lobule.

Front 11

Is conjugated bilirubin a direct or indirect measurement of serum bilirubin?

Back 11

direct

Front 12

What is Gilbert’s syndrome?

Back 12

the most common hereditary cause of increased bilirubin. The main symptom is jaundice which does not require treatment, caused by elevated levels of unconjugated bilirubin in the bloodstream. The source is reduced activity of the enzyme glucuronyltransferase which conjugates bilirubin, preventing bilirubin from being excreted in the bile into the duodenum

Front 13

True/False. Post-hepatic jaundice causes conjugated bilirubinemia

Back 13

True. The problem here is after conjugation and can involve getting the conjugated bilirubin out of the hepatocytes or obstruction in the biliary tract. Note, that there can also be an increase in uncojugated bilirubin in post hepatic jaundice.

Front 14

List a few causes of post-hepatic (obstructive) jaundice.

Back 14

Cancer of the bile ducts, common bile duct stones, cancer of the head of the pancreas, sclerosing cholangitis

Front 15

What would the blood work (specifically bilirubin) look like in a patient with hemolysis?

Back 15

The total bilirubin would be elevated and the conjugated (direct) bilirubin would be normal. This would indicate high unconjugated bilirubin.

Front 16

What is the mechanism of jaundice in the post-hepatic disorders?

Back 16

Obstruction of the bile ducts will eventually cause backup of conjugated bilirubin into the sinusoid of the liver and into the central vein. Furthermore, the bilirubin is unable to reach the duodenum and be excreted in the feces.

Front 17

What does the term "hepatitis" refer to and what class of jaundice would this fall into (pre-hepatic, hepatic, post-hepatic)?

Back 17

It is a broad category of conditions resulting from damage produced by viral, toxic, metabolic, pharmacologic, or immune-mediated attack on the liver. It produces hepatic jaundice.

Front 18

A patient with a strong family history of Gilbert’s syndrome presents to your office with jaundice. What tests could you order and what findings would you expect to support this as a diagnosis?

Back 18

Total and conjugated bilirubin in the blood. Gilbert’s syndrome would cause increased total bilirubin with a normal conjugated bilirubin. Note: The unconjugated bilirubin is an indirect measurement obtained from the total and conjugated (direct) bilirubin results.

Front 19

A patient appears to have high total bilirubin but the conjugated bilirubin is within normal range. What does this mean and how would you classify the cause of this jaundice? (pre-hepatic, hepatic, post hepatic)

Back 19

High total bilirubin with normal conjugated bilirubin indicates unconjugated bilirubin is elevated and the jaundice could have a pre-hepatic cause.

Front 20

A patient with a history of sudden onset jaundice comes in to the office to review her recent bloodwork. The lab results show an increase in total bilirubin and an increase in conjugated bilirubin. What would you expect to see on your differential diagnosis?

Back 20

Obstruction disorders (ie. common bile duct stones, sclerosing cholangitis, tumours (bile duct or head of pancreas). You may also include hepatitis and other hepatic causes of jaundice.

Front 21

What would the blood work look like in a patient with gall stones obstructing the common bile duct?

Back 21

Elevated total bilirubin AND elevated conjugated (direct) bilirubin.