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2008A Q18

The initial luminal digestion of dietary starch by salivary and pancreatic amylase leads to the formation of which disaccharide?
A. Fructose.
B. Galactose.
C. Glucose.
D. Maltose.
E. Sucrose.



D. Maltose.



Exocrine pancreas insuffiency can be caused by CF, Shwachman-Diamond Syndrome and diabetes.

What enzymes are secreted by the pancreas and what do they digest?

  • Trypsin and chymotrypsin - proteins
  • Amylase - starch, carbohydrate, glycogen
  • Lipase, cholesterol esterase, phospholipase - fats


Describe carbohydrate digestion.

Small digestion by salivary amylase.

Mostly due to pancreatic amylase in small intestine.

Hydrolized to maltase, isomaltase, sucrase and lactase.

Absorbed by brush border.


Describe protein digestion.

Pepsin in stomach degrades protein into peptides.

Trypsin and chymotrypsin continue the digestion in small intestine.




Discribe fat digestion.

Bile salts emulsify fats in the small intestine forming micelles.

Pancreatic lipase and co lipase degrades most of fatty acids.

Further hydrolized by phospholipase and pancreatic cholesterol esterase.

Absorbed in small intestine.


Low ALP, consider ??

Zinc deficiency


Alagille syndrome

Mutation of chromosome 20p

  • Pulmonary artery stenosis
  • paucity of small intrahepatic ducts
  • butterfly vertebrae
  • abnormal radius/ulna
  • embryotoxin of eye
  • characteristic facies - pointed chin, prominent forehead


How should neonatal transmission of Hep B be managed?

  • Vaccinate at birth
  • VZIG at birth and vaccinate at 6/52, 3/12, and 5/12
  • Check HBsAG and anti HBs at 5/12

2-3% don't respond to vaccinations

2-3% develop Hep B anyway


What does HBeAg indicate?

Present after HBsAg and indicates a high level of infectivity and replication.


What indicates an inactive carrier state in Hep B?

HBeAg negative

Anti HBe Antibody positive

Lower viral load

Normal LFTs


At delivery, what events increase risk for maternal transmission of Hep C

  • PROM
  • Internal fetal monitoring


Is breastfeeding contraindicated in a mother with Hep C?

No, not contraindicated.

HCV detected in breast milk and colustrum, however, rates of infection are the same b/w breast fed and BMS babies.


What is Wilsons disease?

Difficulty excreting excess absorbed copper from the liver.

Look for raised liver enzymes and reports of decreased performance at school.


  • serum copper
  • free ceruloplasmin
    • decreased in Wilsons because it is mostly bound to copper. It is the copper carrying protein)
  • Urine copper with penicillamine challenge
  • Liver copper
  • Eye R/V


Gilbert Syndrome

  • 2-10% population
  • Benign genetic condition
  • Mild indirect hyperbilirubinaemia
  • Jaundice increased during stress or fasting
  • No treatment necessary


Autoimmune Hepatitis (AIH)

Types 1 and 2

Present with malaise, wt loss, anorexia due to cirrhosis, portal HTN

Albumin low, total protein high

Raised immunoglobulins increase the total protein (TP = albumin + globulin)

Diagnosis by serum antibodies, increased aminotransferase, increased protein.

Treat with immunosuppression

  • steroids
  • azathioprine


Intrahepatic biliary atresia causes......

pale stool and conjugated hyperbilirubinemia


In portal hypertension, you see splenomegally, oesophageal varices and low platelets, but bleeding unlikely.

Why do these signs occur?

In congested liver, blood flow which normal is directed from stomach to liver, is instead directed to spleen which becomes enlarged from excessive blood product breakdown. The only platelets not removed are the very young, sticky platelets which are in such good condition they can prevent bleeds even tho platelets low.

After leaving the spleen, blood flows to the oesaphagus and then back to the heart. This increased flow accumulates in varicose veins causing varices.


In a jaundiced infant, what should you think of? (per gastro exam tips)

Pale stool

Heart murmur


Pale stool = biliary atresia

Heart murmur = Alagilles

Low GGT = Progressive Familial Intrahepatic cholestasis


In teenagers what should you think of for the following (per gastro exam tips)

  1. Decreasing school performance
  2. High globulin or any mention of autoimmunity


  1. Decreasing school performance = wilsons
  2. High globulin or autoimmunity = Autoimmune hepatitis


In the treatment of chronic Hep C with Ribavirin, what is the most common side effect?

Haemolytic anaemia


What type of virus is HCV?

Single stranded, enveloped RNA


Ribavirin is used in the treatment of acute Hep C infection. What is the most common side effect?



What is the risk of vertical transmission to the neonate is mother is HBsAg +tive and HBeAG positive?



What is the risk of vertical transmission to the neonate if mother is HBsAg +tive and HBeAg -tive?



If mother gets an acute Hep B infection during pregancy, what is the risk of transmission to the neonate:

a. in the first trimester?

b. in the third trimester?

a. 10%

b. 80-90%


What managment should apply at birth to the babies of the following mothers?

1. HBsAg -

2. HBsAg +, HBeAg +

3. HBsAg +, HBeAg -

4. Unknown

1. Routine immunisation

2. Hep B vacc and Hep B IG

3. Hep B vacc and Hep B IG

4. Hep B immunisatin at birth and check HBsAg status


So....any baby with HBsAg positive gets the immunoglobulin


In a a patient with IBD, what other autoimmune conditions should be considered in the context of deranged LFTs?

Autoimmune hepatitis and sclerosing cholangitis.


In autoimmune hepatitis and sclerosing cholangitis, what additional investigations to LFTs would you expect to be deranged?



LKM + (liver/kidney microsomal antibody)

IgG ++

Normal USS and MRCP



IgG +

USS and MRCP abnormal


What LFT derangements would you expect to see in a patient with non alcoholic fatty liver disease?

Elevated AST and ALT, typically 2-5 times the upper limit of normal. 

AST:ALT ratio <1 (cf etoh liver disease which is >2)


In a faecal analysis what do fat globules and fatty acid crystals indicate?

Fat malabsorption.

Crystals indicate partial hydrolysis.

Common causes included coealiac disease, pancreatic insufficiency, cholestasis, bacterial overgrowth.