Module 3 - Hepatic & Lipid Tests Flashcards
(88 cards)
1
Q
What are some functions of the liver?
A
- cholesterol synthesis and excretion
- removal of old RBCs
- activation of vitamin D
- detoxification and metabolism
- synthesis of proteins and clotting factors (albumin, INR)
- processes nutrients
- storage (glycogen, fats, iron, copper, vitamins)
2
Q
What are considered “synthesis tests”?
A
- INR
- albumin
3
Q
What are considered “cholestatic tests”?
A
- ALP
- GGT
- Bilirubin (conjugated)
4
Q
What are considered “hepatocellular damage tests”?
A
- AST/ALT
- LDH
- Bilirubin (total)
5
Q
What are LFTs?
A
liver function tests
*not really accurate since many of the tests included in a LFT panel don’t measure function, they measure damage
6
Q
_____ is responsible for producing clotting factors
A
Liver
*If liver is substantially diseased (>80% loss of function) clotting factors are dysfunctional or l=not produced
7
Q
Abnormal clotting factors = _______ INR
A
increased
8
Q
What things can increase INR?
A
- warfarin
- antibiotics (decreased vitamin K production in gut)
- malabsorption of vitamin K
- genetic clotting factor deficiencies
9
Q
______ is a protein synthesized from amino acids in the liver
A
Albumin
10
Q
What is albumin important for?
A
- maintaining osmotic pressure in the blood (albumin expands blood volume)
- transport of hormones, drugs, fatty acids and ions
11
Q
Half life of albumin?
A
Long half-life (20 days)
12
Q
Possible reasons for albumin to be low?
A
- malnutrition
- loss in the urine (kidney disease)
- severe burns
- large amounts of fluid administration (dilution)
- pregnancy (dilution)
13
Q
Bilirubin metabolism:
Starts off with ?
A
Breakdown of RBCs
14
Q
Bilirubin metabolism:
Hemoglobin converted to bilirubin in _____
A
spleen
15
Q
Bilirubin metabolism:
Liver makes bilirubin ______ ______
A
water soluble (direct or conjugated bilirubin)
16
Q
Bilirubin metabolism:
_____ bilirubin is excreted into the bile
A
Conjugated
17
Q
Bilirubin metabolism:
Conjugated bilirubin ends up in the ______ to be excreted in stool (brown color)
A
intestines
18
Q
Bilirubin metabolism:
If there is a blockage in the bile duct (cholestastis), conjugated bilirubin can be found in the _____
A
urine
19
Q
Direct bilirubin = ______
A
soluble (in water)
20
Q
Indirect bilirubin = _______
A
insoluble
21
Q
Should direct/conjugated bilirubin be in the blood?
A
NO WAY
22
Q
What does an elevated direct bilirubin level indicate?
A
that something is preventing bile flow to the intestines
**liver is working (conjugating) but it can’t get rid of the water-soluble bilirubin due to obstruction or damaged liver cells
23
Q
What are potential causes of having increased levels of direct bilirubin?
A
- obstruction of the bile duct
- intrahepatic cholestasis
- hepatitis
- toxins
- cirrhosis
24
Q
What is ALP?
A
Alkaline Phosphatase (ALP) -A group of isoenzymes that remove phosphate groups from molecules (exact function of these isoenzymes still being discovered)
25
ALP:
| ____% in liver and bone
80
26
ALP:
| ___% in the intestine
20
27
What types of people may have an elevated ALP?
- children and adolescents have higher ALP due to bone development
- pregnancy (placental ALP)
- elevated in bone disorders (i.e. fractures, cancers)
28
ALP is also elevated in pts with _______ disease
cholestatic
| *bile accumulation = increased ALP synthesis
29
How long does it take for ALP to be elevated in patients with cholestatic disease?
4-6 weeks for elevation to occur (SLOW)
30
Once obstruction is resolved, ALP returns to normal in _____ weeks
2-4
31
Since ALP is a non-specific test, what do you need to interpret it with?
GGT
32
What is GGT?
Gamma-Glutamyl Transferase
| -enzyme that carries gamm-glutamyl functional groups
33
GGT is ______ for cholestatic disorders but not ______.
it is sensitive but not specific
| good for ruling out cholestasis but not good for ruling it in
34
GGT may be elevated after an _____ ______
myocardial infarction
35
GGT is strongly associated with ?
alcoholic liver disease
36
GGT/ALP ratio > 2.5 is indicative of what?
ethanol abuse
37
Abstinence from alcohol can reduce GGT by ___% in 2 weeks
50
38
List a few drugs that can cause cholestasis
- NSAIDs
- oral contraceptives
- B-lactams
- amiodarone
* more on slide 16
39
ALT converts what?
alanine to glutamate
40
AST converts what?
aspartate to glutamate
41
Describe AST
Aspartate Transaminase (AST):
- found in liver as well as heart, skeletal muscle, kidneys, brain, pancreas, spleen, lungs and RBCs
- less specific to the liver than ALT
- half life of 17 hours
42
Describe ALT
Alanine Transaminase:
- More specific to the liver than AST (but can still be found in other tissues such as kidneys, heart, muscle and pancreas)
- Half life of 47 hours
43
AST & ALT are generally higher in the _______
afternoon
44
Vigorous exercise can ______ AST/ALT (muscle breakdown)
increase
45
Dialysis can _____ AST/ALT levels
decrease
46
Transaminase levels don't correlate with disease _______
severity
47
Most of bilirubin is ______
unconjugated
48
Why might total bilirubin be elevated in hepatocellular injury?
hepatocyte damage = decreased bile production/flow
49
Symptoms of hyperbilirubinemia?
- jaundice
- pruritus
- xanthomas (lipid deposits in skin)
50
In premature babies, high bilirubin can cause _____
kernicterus
51
What is kernicterus ?
rapid RBC breakdown - BBB not formed + liver enzymes not formed = bilirubin buildup in the brain = DAMAGE
52
What is LDH?
Lactate dehydrogenase:
| -an enzyme responsible for converting lactate to pyruvate (and vice versa) in anaerobic metabolism
53
Why is LDH not really that clinically useful?
it is non-specific to the liver
54
What may LDH be helpful in differentiating?
Causes of acute liver injury
55
ALT/LDH ratio > 1.5 = ?
viral hepatitis
56
ALT/LDH ratio < 1.5 = ?
ischemic hepatitis or acetaminophen toxicity
57
What are some signs and symptoms of hepatic injury/disease?
- right upper quadrant pain
- jaundice
- pruritus
- ascites (fluid accumulation in peritoneal cavity)
- malaise/fatigue
- malnutrition/anorexia/muscle wasting
58
What test results would indicate cholestasis?
```
increased ALP
AND
increased GGT
AND
increased conjugated bilirubin
```
59
What test results would indicate hepatoceullar injury?
```
increased AST/ALT
AND/OR
increased bilirubin
AND/OR
increased LDH
```
60
What does idiosyncratic mean?
not dose-related
61
What are examples of idiosyncratic causes (not dose-related)?
Allergic reaction
Bile duct injury
Hepatocellular injury
62
What are examples of drugs that can cause dose-related hepatotoxicity?
- TYLENOL MAN
| - Also cocaine and meth
63
LDL = _____
bad
64
HDL = _____
good
65
LDL formula
LDL = total cholesterol - HDL - (TGs/2.2)
66
If TGs are too high (> 4.5 mmol/L) LDL is _____
inaccurate
67
What does HDL do?
scavenges cholesterol out of vessels and tissues
68
After eating, TGs appear in plasma ____ hrs after a meal and peak in _____ hours and can persist for up to 14 hours
2 hrs
| 4-6 hrs
69
What type of patients have high TGs?
- diabetes
- kidney disease
- obesity
- liver disease/alcoholism
70
What type of medications can increase TG and LDL levels?
steroids, antipsychotics, thiazide diuretics
71
For most patients, LDL target is ??
50% reduction or < 2 mmol/L
72
What is CK?
Creatine Kinase:
| -enzyme that stimulates transfer of high-energy phosphate groups
73
CK can be used as a marker for what?
muscle injury/death (MI, myopathies)
74
What type of people can have elevated CK?
marathon runners or people who do intense physical activity
75
What is a myopathy?
A general term referring to any muscle disease
| *CK levels N/A
76
What is myalgia?
Muscle pain or weakness
| *CK levels normal
77
What is myositis?
A myalgia with increased CK levels
| *Increased but <10x ULN
78
What is rhabdomyolysis?
Muscle symptoms with marked CK elevation and renal symptoms (creatinine elevation)
*CK levels > 10-25x ULN with renal symptoms
79
When should CK decline if you stop a statin and that was the cause of the muscle pain?
in 3-4 days
80
What lipid ab tests do you order when a pt is on statin?
| **THIS IS DIFFERENT FROM WHAT WE LEARNED IN CLINICAL
TC, LDL, HDL, TC/HDL, TG
81
When do you order these lipid lab tests when on a statin?
Baseline, 6-8 weeks after initiation, then every 6 months
82
What lab tests do you order for liver injury?
AST/ALT
83
When do you order liver injury lab tests?
Baseline, then only if symptoms are present
84
If AST/ALT > ____ ULN consider stopping statin
3x
85
What lab tests do you order for muscle injury when on statin?
CK
86
When do you order muscle injury lab tests?
Baseline, then only if symptoms present
87
If CK > ____ ULN then STOP statin. When resolved, decrease dose or switch statin
10x
88
If CK < 10x ULN, what do you do?
continue but lower statin dose
