S6: liver pathology, jaundice & LFTs

Question 1

Outline the main roles of the liver

Answer 1

Storage – glycogen, vitamins, iron & copper
Synthetic – glucose, lipids/cholesterol, bile, clotting factors & albumin
Metabolic – bilirubin, ammonia, drugs, alcohol, carbohydrates & lipids

Question 2

List acute causes of liver pathology

Answer 2

Alcohol
Paracetamol
Viral
Medications

Question 3

Describe symptoms of liver disease

Answer 3

Jaundice
Oedema/ascites
Bleeding
Confusion

Question 4

Describe drugs as a cause of cirrhosis

Answer 4

Iatrogenic
Alcoholic liver disease
-fatty change: weeks -> hepatomegaly
-alcoholic hepatitis: years -> RUQ pain & jaundice

Question 5

Describe infection as a cause of cirrhosis

Answer 5

Hep B – vaccine, no cure, symptoms
Hep C – cure, no vaccine, asymptomatic
-increased risk of malignancy

Question 6

Describe deposition as a cause of cirrhosis

Answer 6

Fat
-non-alcoholic fatty liver disease: insulin resistance, triglycerides
-non-alcoholic steatohepatitis: liver inflammation
Hereditary haemochromatosis – increased absorption of iron = increased deposition (increased ferritin)
-autosomal recessive & treatment is venesection
Wilson’s disease – decreased copper secretion = increased deposition (decreased ceruloplasmin in CNS)

Question 7

List autoimmune conditions which cause cirrhosis

Answer 7

Autoimmune hepatitis
Primary biliary cirrhosis
Primary sclerosing cholangitis

Question 8

Describe the portal circulation

Answer 8

Circulation of nutrient-rich blood between the gut and liver
Enables the liver to remove any harmful substances that may have been digested before the blood enters the main blood circulation around the body

Question 9

Describe portal hypertension and clinical signs

Answer 9

Can result when blood flow into the liver from the portal vein is restricted 
When pressure increases in the vein, it can result in blood flowing through normally unused connections between the portal venous system & systemic system -> connecting blood vessels can become symptomatic -> oesophageal varices (can bleed torrentially causing haematemesis) 
Splenomegaly 
Ascites (increased hydrostatic pressure)

Question 10

Describe how liver pathology can cause hepatorenal syndrome

Answer 10

Portal hypertension
Arterial vasodilation
Perceived as decreased circulating volume
RAAS
Renal artery vasoconstriction (decreased perfusion -> decreased kidney function)

Question 11

Describe the formation and composition of gallstones

Answer 11

Made up of cholesterol & bile pigments (components come out of solution to form a solid)
Most common: diet, female, forties & pregnancy
Can be asymptomatic but tend to cause problems when they move from the gallbladder into the biliary tree

Question 12

List the 4 most common complications of gallstones

Answer 12

Biliary colic
Acute cholecystitis
Ascending cholangitis
Acute pancreatitis

Question 13

Describe biliary colic as a complication of gallstones

Answer 13

RUQ pain
Temporary obstruction of the cystic duct
No inflammation

Question 14

Describe acute cholecystitis as a complication of gallstones

Answer 14

Gallstone becomes impacted within the cystic duct – inflammation occurs
RUQ pain
Murphy’s sign - pain occurs on inspiration when gallbladder comes into contact with examiner’s hand

Question 15

Describe ascending cholangitis as a complication of gallstones

Answer 15

Charcot’s triad = RUQ pain, fever & jaundice

Gallstone moves into CBD and becomes impacted

Question 16

Describe acute pancreatitis as a complication of gallstones

Answer 16

Gallstone becomes impacted in the distal biliary tree (blocking secretions from the pancreas)
Pro-enzymes that normally are only activated in the lumen of the gut become prematurely activated within the ductal system of the pancreas -> degree of auto-digestion and inflammation

Question 17

Define jaundice

Answer 17

Clinical manifestation of raised plasma bilirubin

Question 18

Describe the different types of jaundice

Answer 18

Pre-hepatic: too much haem breakdown; raised unconjugated bilirubin
Hepatic: reduced liver function; mixture of conjugated/unconjugated bilirubin
Post-hepatic: obstruction of the biliary tree; raised conjugated bilirubin

Question 19

Describe causes of the different types of jaundice

Answer 19

Pre-hepatic: haemoglobinopathies & haemolysis
Hepatic: chronic liver damage & acute liver damage
Post-hepatic: gallstones, biliary stricture & pancreatic carcinoma (head of pancreas)

Question 20

List the different tests in an LFT

Answer 20

Albumin – synthetic function
ALT – alanine transaminase (increased levels = acute)
AST – aspartate transaminase (increased levels = chronic); can be increased in skeletal muscle, cardiac muscles & RBCs damage
ALP – alkaline phosphatase (bile duct damage – confirm with gamma–GT)
Bilirubin

Question 21

Describe symptoms of post-hepatic jaundice

Answer 21

Pathway for bilirubin excretion is blocked
Can get symptoms related to the absence of bilirubin in the gut (pale stools) & presence of bilirubin in the urine (dark urine)

Question 22

Describe the LFT results for haemolysis (pre-hepatic jaundice)

Answer 22

ALT, AST & ALP normal

Increased bilirubin levels

Question 23

Describe the LFT results for hepatocellular damage

Answer 23

ALP & bilirubin normal

ALT & AST raised

Question 24

Describe the LFT results for acute pancreatitis

Answer 24

ALT & AST normal

ALP, bilirubin & amylase raised

Question 25

Describe the LFT results for liver metastases

Answer 25

Mixed picture – hepatic & post-hepatic jaundice

ALT, AST, ALP & bilirubin raised