Normal and abnormal liver function: Waters

Question 1

Describe some complications of liver dz.

Answer 1

Synthetic impairment
Cholestasis- impaired bile flow
Decr. clearance of waste/toxins from blood
Portal hypertension- blood shunted around liver and therefore not processed

Question 2

Describe how liver functions tests test liver function.

Answer 2

They measure how quickly the liver clears certain drugs, such as lidocaine, from the blood. Other tests measure hepatocellular injury or bile flow as indirect function measurements.

Question 3

Which tests measure liver injury?
Which is more specific for liver injury?
Under what circumstance is the liver isoenzyme of ALP elevated?

Answer 3

Aminotransferase tests (ALT, AST) and ALP. 
AST also incr. w/ muscle injury (distance runners, weight lifters, autoimmune dz attacking muscle)
ALT more specific for liver injury.

ALP incr. when bile ducts obstructed.

Question 4

Which tests measure clearance?

Answer 4

Bilirubin

Ammonia- high nitrites in blood = hepatic encephalopathy = severe confusion (don’t recognize relatives)

Question 5

Which tests measure synthetic capacity?

Answer 5

Clotting factors made by liver (I, II, V, VII, X)
Albumin
Cholesterol- late complication of severe dysfunction

Question 6

What would high choleglycine levels indicate?

What is choleglycine?

Answer 6

Cholestasis

It is a bile salt.

Question 7

What is GGT?
What induces its elevation?
Is it a specific test for determining cause of liver damage?
What would an isolated GGT elevation indicate?

Answer 7

Gamma glutamyl transferase (GGT) is an enzyme present in many tissues including biliary ductules.
It incr. w/ cholestasis and biliary obstruction.
Many chemicals can induce its elevation so it has limited clinical utility bc it is not very specific.

ISOLATED rise in GGT indicates medication or EtOH abuse, although even moderate use of EtOH can cause isolated rise in GGT.

Question 8

This test helps give good estimates of prognosis, operative risk, transplantation need.
Describe the balance it represents and what circumstances could cause its elevation in the blood.

Answer 8

Bilirubin

Its levels represent a balance between input and hepatic removal of waste.
It increases w/ impaired clearance by the liver.
It also increases w/ intrahepatic and extrahepatic obstruction.

Question 9

Your friend is post-call, has not been sleeping or eating as well as they should. They appear a bit jaundiced. They are part of the ~3-12% of the gen. pop. with this condition:

Answer 9

Gilbert’s syndrome- It produces elevated levels of unconjugated bilirubin in the bloodstream (hyperbilirubinemia), but this normally has no serious consequences, although mild jaundice may appear under conditions of exertion or stress. -Wiki

Tell them they look like shit and should go sleep/eat.

Question 10

How well does measure of clotting factors I, II, V, VII, X (PT/INR) correlate w/ liver synthetic function?
What would be a superficial sign of poor PT/INR?

Answer 10

Quite well, indeed.

Bruising would be a good indicator of poor PT/INR.

Question 11

What are the Child-Pugh scores? What are they used for?

What factors does this score take into account?

Answer 11

They are scores used to assess severity of liver impairment and surgical risk.
The score takes into account: Alb, Bili, ascites, encephalopathy, and PT/INR

Question 12

What are the 3 factors measured in the Model of End Stage Liver Disease (MELD)?

Answer 12

Bilirubin, PT/INR, Creatinine

Elevated creatinine is a poor prognostic factor for any surgical procedure, and frankly, in general.