Mid-sem test 1: B

Question 1

What is paediatric hyperbilirubinaemia

Answer 1

AKA paediatric jaundice, it is the yellowish discolouration of the sclera and skin in a newborn baby due to high bilirubin levels.

Question 2

List the diseases or syndromes where there are high levels of UNCONJUGATED bilirubin

Answer 2

• Haemolysis eg. HDFN (haemolytic disease of the fetus and newborn)
• Gilbert’s syndrome
• Crigler-Najjar Syndrome (CNJ) I and II
• Physiological Jaundice
• Glucose 6 Phosphate Dehydrogenase Deficiency (G6PD Deficiency)

Question 3

List the diseases or syndromes where there are high levels of CONJUGATED bilirubin

Answer 3

• Dubin-Johnson Syndrome

- Rotor’s Syndrome

Question 4

What is prehepatic jaundice a result of?

Answer 4

High bilirubin production due to excess red blood cell haemolysis (which can be due to an autoimmune disease or HDFN).
The result is an increase in unconjugated bilirubin as hepatocytes cannot keep up with demand for conjugation

Question 5

What is Intrahepatic jaundice a result of?

Answer 5

Impaired uptake, conjugation or secretion of bilirubin due to hepatocyte dysfunction

Question 6

What is posthepatic jaundice a result of?

Answer 6

Increased conjugated bilirubin in circulation due to obstruction to bile tree/canaliculi.
The result is pale stool and dark faeces

Question 7

What can happen if there is hyperbilirubinaemia in neonates and is this pathological or physiological?

Answer 7

1. Jaundice
2. Acute bilirubin encephalopathy
3. Kernicterus

physiological

Question 8

Fully explain the three phases of acid secretion

Answer 8

• Cephalic
the sight, smell, taste or thought of food stimulate processes in the brain to activate enteric neurons via the parasympathetic preganglionic neurons travelling in the vagus nerve
• Gastric
food in the stomach stimulates acid secretion. Peptides and amino acids in food stimulate G cells to release gastrin, a hormone which stimulates acid secretion. Food also acts as a buffer for lowering the pH – this removes stimulus for somatostatin secretion (which would inhibit acid secretion)
• Intestinal
chyme enters the duodenum. Intestinal phase stimuli activate negative feedback mechanisms to reduce acid secretion and prevent chyme from becoming too acidic. Enterogastrones are the hormones which do this (CCK, secretin, GIP, GLP-1)