14. Jaundice Flashcards Preview

YR3: MM FC Ed. > 14. Jaundice > Flashcards

Flashcards in 14. Jaundice Deck (35)
Loading flashcards...
1

What 3 steps can bilirubin metabolism be summarised into?

Production of unconjugated bilirubin
Conjugation of bilirubin
Excretion of bilirubin

2

What is prehepatic jaundice?

Jaundice caused by excessive production of BR
Extravascular + intravascular

3

What is hepatic jaundice?

Jaundice due to pathology in the liver (hepatocytes + bile canaliculi)

4

What is posthepatic jaundice?

Jaundice caused by problems with biliary flow

5

What is obstructive jaundice?

Jaundice caused by lack of bile flow into the gut
Results in pale faeces (lack of urobilin/stercobilin) + dark urine (conjugated BR)

6

What is cholestatic jaundice?

Jaundice caused by BR not flowing out the common bile duct
Can be due to gallstones, ileus or CBD peristalsis (drug induced)

7

What is unconjugated jaundice?

Jaundice caused by accumulation of unconjugated BR
Due to excessive production of unconjugated BR or decreased capacity to conjugate BR

8

What causes increased production of bilirubin?

Intravascular haemolysis
Congenital: G6PD, PKD, SCD + thalassemia
Acquired: artificial heart valves, DIC, malaria

Extravascular haemolysis
Congenital: hereditary spherocytosis
Acquired: AI haemolysis

9

What causes decreased conjugation of bilirubin?

Decreased hepatocyte uptake: contrast agents + portosystemic shunts to bypass a cirrhotic liver

Congential enzymatic problems: Gilbert's

10

What causes decreased excretion of bilirubin?

INVITED MD
Infection: hepatitis, ascending cholangitis, liver abscess
Neoplastic: mets, HCC, cholangiocarcinoma + pancreatic
Vascular: Budd chiari syndrome
Inflammation: PBC, PSC, AI hepatitis, pancreatitis
Trauma: gallstones, stricture after ERCP
Endo: intraheptic cholestasis of pregnancy
Degenerative: none
Metabolic: Wilson's, haemachromatosis
Drugs: some affect ability of hepatocytes to excrete BR- alcohol, paracetamol, valproate + rifampicin. Some cause biliary ileus: nitrofurantoin, OCP

11

What questions should you ask in the presenting complaint in someone with jaundice?

Acute/ chronic?
Pregnant?
Associated symptoms:
RUQ pain, N+V, pruritus (hepatitis)
Fever or diarrhoea (viral hepatitis/ abscess)
Steatorrhoea, dark urine, pruritus (obstructive jaundice)
Weight loss, fever, night sweats (malignancy)
Bronzed skin + DM (haemochromatosis)
Exposure to outdoor water/ sewage (risk factor for leptospirosis)

12

What should you ask in the PMHx in someone with jaundice?

Gallstones
Liver disease
Haemophilia
Recent blood transfusion/ surgery
Ulcerative colitis
Diabetes
Emphysema (suggests alpa 1 antitrypsin deficiency)

13

What should you ask about in the social history in someone with jaundice?

Excessive alcohol consumption
IV drug use
Unprotected sex/ multiple partners
Foreign travel
Tattoos

14

What physiological processes occur in production of unconjugated BR?

RBCs broken down by macrophages in spleen
Hb degraded into iron + insoluble BR
Insoluble BR travels to liver bound to albumin

15

What physiological processes occur in conjugation of BR?

Hepatocytes uptake unconjugated BR
Conjugate to glucuronate making it water soluble

16

What physiological processes occur in excretion of BR?

Conjugated BR secreted into bile canaliculi
Flows with bile into duodenum
Metabolised by bacteria into colourless urobilinogen + stercobilinogen
Some reabsorbed in gut + excreted via kidneys
Majority oxidised in gut to coloured pigments (urobilin + stercobilin) giving faeces its brown colour

17

What is conjugated jaundice?

accumulation of conjugated BR

18

By what 4 mechanisms can drugs cause haemolysis?

Intravascular: Sulphonamides
AI, extravascular: Methyldopa
Hepatitis: Paracetemol OD
Cholestasis: Co-amoxiclav

19

What 7 familial conditions can cause jaundice?

Gilbert's syndrome
Haemochromatosis
Wilson's disease
Sickle cel disease
Thalassaemia
Hereditary spherocytosis
G6PDH deficiency

20

What is haemochromatosis?

Deficiency of iron regulatory hepcidin.
Allows increased intestinal absorption of iron causing accumulation in tissues, esp. the liver, which may lead to organ damage.

21

What is Gilbert's syndrome?

Defected gene for conjugating enzyme
Results in unconjugated hyperbilirubinaemia

22

What is usually the cause of elevated AST > ALT?

Excessive alcohol intake

23

What is usually the cause of elevated ALT > AST?

Viral hepatitis

24

In which 3 situations may you see AST and ALT elevated into the 1000s?

Viral hepatitis
Paracetamol OD
Ischaemic hepatitis

25

What is suggested by a raised ALP and GGT?

Bile duct pathology (obstruction)

26

What is suggested by a raised ALP and normal GGT?

Increased bone turnover (malignant bone mets, primary hyperparathyroid)

27

What is suggested by a raised GGT in isolation?

Recent alcohol consumption

28

What does bilirubin in the urine signify?

Posthepatic jaundice

29

Which antibodies should you include in an autoimmune screen for cause of jaundice with raised liver enzymes?

Antinuclear antibodies (ANA)
Antismooth muscle antibodies (ASMA): Type 1 AI hepatitis
Antimitochondrial antibodies (AMA): PBC + some AI hepatitis

30

What pathophysiological process occurs in PBC?

AI destruction of the small interlobular bile ducts
Causes intrahepatic cholestasis which damages cells, leading to scarring, fibrosis + eventually cirrhosis.