alimentary disease

Question 1

what is jaundice

Answer 1

yellow discolouration of sclerae and skin due to raised bilirubin, and is clinically detectable when serum bilirubin >40umol/litre

Question 2

3 categories of jaundice

Answer 2

haemolytic, jaundice caused by congenital hyperbilirubinamias, cholestatic

Question 3

what is affected in prehepatic jaundice

Answer 3

conversion of Hb to bilirubin

Question 4

cause of prehepatic jaundice

Answer 4

haemolysis

Question 5

what is affected in intrahepatic cholestatic jaundice

Answer 5

conjugation of bilirubin

Question 6

causes of intrahepatic cholestatic jaundice

Answer 6

viral hepatitis, drugs, alcoholic hepatitis, cirrhosis, pregnancy, recurrent idiopathic cholestasis, some congenital disorders, infiltrations

Question 7

what is affected in extrahepatic cholestatic jaundice

Answer 7

failure of bile secretion by liver, or bile duct obstruction

Question 8

causes of extrahepatic cholestatic jaundice

Answer 8

common duct stones, carcinomas in bile duct, head of pancreas and ampulla, biliary structure, sclerosing cholangitis, pancreatitis, pseudocyst

Question 9

example of haemolytic anaemia

Answer 9

sickle cell disease

Question 10

process of haemolytic jaundice

Answer 10

increased erythropoiesis → increased production of bilirubin → jaundice

Question 11

does bilirubin in haemolytic jaundice pass into urine

Answer 11

no as not water soluble as unconjugated

Question 12

liver biochemistry for haemolytic jaundice

Answer 12

increased serum urobilinogen, otherwise normal

Question 13

cause of jaundice caused by congenital hyperbilirubinaemia

Answer 13

impaired conjugation of bilirubin with glucoronic acid, or bilirubin handling by liver

Question 14

liver biochemistry for jaundice caused by congenital hyperbilirubinaemia

Answer 14

raised bilirubin, otherwise normal

Question 15

what is the commonest cause of congenital hyperbilirubinaemia

Answer 15

Gilbert’s syndrome

Question 16

how does Gilbert’s syndrome lead to congenital hyperbilirubinaemia

Answer 16

autosomal dominant; mutation in gene coding for UDP-glucuronyl transferase → reduced enzyme activity → reduced conjugation of bilirubin

Question 17

how is Gilbert’s syndrome picked up

Answer 17

incidental finding of slightly raised serum bilirubin as asymptomatic

Question 18

triggers of Gilbert’s syndrome that lead to jaundice

Answer 18

dehydration, fasting, viral illness

Question 19

diagnosis of jaundice caused by congenital hyperbilirubinaemia

Answer 19

raised unconjugated hyperbilirubin, otherwise normal liver biochemistry, normal full blood count, smear and reticulocyte count (differentiate from haemolysis), absence of signs of liver disease

Question 20

management of jaundice caused by congenital hyperbilirubinaemia

Answer 20

reassurance that no further investigation or treatment necessary

Question 21

other causes of jaundice caused by congenital hyperbilirubinaemia

Answer 21

Crigler-Najjar, Dubin Johnson, Rotor’s syndromes

Question 22

what causes intrahepatic cholestasis

Answer 22

hepatocellular swelling or abnormalities at cellular level of bile excretion

Question 23

what causes extrahepatic cholestasis

Answer 23

obstruction of bile flow at any point distal to bile canaliculi

Question 24

characteristics of cholestatic jaundice

Answer 24

conjugated bilirubin, pale stool, dark urine, abnormal liver biochemistry