BT_PO 1.103 Describe the storage, synthetic, metabolic, immunological and excretory functions of the liver and identify the physiological consequences of hepatic disease

T/F  liver failure can result in hypoglycaemia due to limited / absent –  (i) glycogen storage and (ii) gluconeogenesis

T/F  liver disease can result in coagulopathy, because the liver produces all of the clotting factors

T/F  Kupffer cells are macrophages which line the hepatic sinusoids – with severe liver disease these may be absent, placing the patient at risk of sepsis from GIT flora

T/F  biliverdin (from haem breakdown) undergoes active transport into hepatocytes where it is metabolised to bilirubin – this is why liver disease can produce jaundice

T/F  one cause of hepatic encephalopathy is high ammonia levels – this results from impaired conversion of nitrogenous compounds (derived from protein), to urea. Lactulose is used in patients with encephalopathy because it decreases intestinal ammonia production.

T/F  portal hypertension leads to intestinal wall oedema, which reduces the absorptive capacity of the GIT

T/F  (not in the primary exam) gynaecomastia occurs in men with chronic liver disease because the free oestrogen : testosterone ratio is altered by a reduction in sex-hormone binding globulin

References
1. Miller 8th edition, Chapter 22
2. Kam and Power 3rd edition, Chapter 6

Hepatic metabolism of drugs

BT_PO 1.108

Describe the alteration to drug response due to hepatic disease.

Metabolic clearance is usually constant and independent of dose. TRUE/FALSE

For drugs with an extraction ratio of nearly 0, a change in liver blood flow produces a nearly proportional change in clearance. TRUE/FALSE

Alfentanil is an example of a drug whose hepatic metabolism is capacity-limited. TRUE/FALSE

In cirrhosis, hepatic drug clearance is usually reduced. TRUE/FALSE

CYP3A4 is responsible for nearly half of all drug metabolism. TRUE/FALSE. Hint…this is the enzyme system affected by grapefruit juice (and interestingly, propofol).

2017.1 : SAQ 15

Outline the clinical laboratory assessment of liver function

BT_PO 1.106

Many of our drugs are metabolised by the liver, and many of our procedures rely on normal coagulation status.

An elevation in AST is related to zone 1 damage   TRUE/FALSE

Hypoalbuminaemia is seen within 48 hours of a hepatic insult  TRUE/FALSE

There will be hyperglycaemia in severe hepatic insufficiency  TRUE/FALSE

Urea will be low in severe hepatic insufficiency  TRUE/FALSE

Biliary obstruction can cause a high INR  TRUE/FALSE