Waters Flashcards
complications of liver disease
- synthetic impairment
- cholestasis
- decreased clearance
- portal HTN
Tests of liver synthetic capacity
clotting factors
albumin
cholesterol: late complication of severe dysfunction
cholestasis
impairment of bile flow
Tests that measure liver clearance
bilirubin: imperfect
ammonia
portal HTN
portal blood is shunted around liver rather than processed by the liver
bilirubin
balance btwn input and removal by liver
increases with intrahepatic/extrhepatic obstruction
normal: 1
Tests that detect liver injury
aminotransferases: ALT, AST
ALP
AST (aspartate aminotransferase))
liver and muscle injury
ALT (alanine aminotransferase)
more specific for liver
ALP (alkaline phosphatase)
bile ducts: correlates with intrahepatic and extra hepatic injury or obstruction
level associated with increases synthesis
isoenzymes: Gut, Liver, Bone
Cholylglycine
serum bile salt
correlates with degree of cholestasis, intrahepatic of extra hepatic obstruction to bile flow
GGT (Gamma Glutamyl Transferase/Transpepidase)
many tissues
biliary
increased: cholestasis, biliary obstruction; Phenytoin and ethanol
limited clinical utility: many meds and chemicals increase it
isolated GGT elevation
due to medications or ETHANOL
ammonia
detoxified in liver by urea cycle and glutamine synthetase
correlation: hepatic encephalopathy
prolonged prothrombin time
clotting factor deficiency: I, II, V, VII, X
Vit. K deficiency
correlates with hepatic synthetic function
international standardized ratio (INR)
correlates with hepatic synthetic function
albumin
correlates with hepatic sun.
half life 20 days
rapidly changes with acute illness, malnutrition
Child Pugh score
score 1; 2; 3
prognosis after vatical bleeding
1. albumin: greater than 3.5; 2.8-3.5; less than 2.8
2. bilirubin: less than 2; 2-3; greater than 3
3. ascites: none; mild; mod.-sev.
4. encephalopathy: none; 1-2; 3-4
5. PT/INR: less than 1.71; 1.71-2.2; greater than 2.2
Grade A: 5-6
Grade B: 7-9
Grade C: 10-15
prognosis: grade A better survival (C nearly half die in 1-2 months)
Model of End-Stage Liver Disease (MELD)
predictor of ALD survival 1. INR 2. bilirubin 3. creatinine: high is bad (should be low due to muscle wasting and malnutrition in liver disease) High MELD: increase 90 day mortality
Where does the majority of liver blood flow come from?
Portal vein (splenic vein, splanchnic circulation)
rest: hepatic artery
How does chronic portal HTN lead to increased splanchnic blood flow and perfused capillary density?
- increased transvascular pressure gradient
- portosystemic shunting
- increase circulating levels of Glucagon and other vasodilators: decreases catecholamine sensitivity
- decreases splanchnic arteriolar resistance
How does chronic portal HTN lead to increased lymph flow?
- venous stasis
- capillary and postcapillary venule pressure (also due to decreased splanchnic arteriolar resistance)
- increase capillary filtration rate (also due to increased perfused capillary density)
What do venous collaterals in portal HTN cause (via what vein)?
- anterior
- posterior
- superior
- inferior
- caput medusa (via umbilical vein)
- splenorenal shunt (via retroperitoneal veins)
- esophageal varcies (azygous)
- hemorrhoids/ anorectal varices
varices
- how many have them in newly Dx cirrhosis
- how many bleed within 2 year
- why do they bleed
- Tx
tortuous venous collaterals under high pressure
1. half (increases each year after Dx)
2. 1/3
3. high pressure, thrombocytopenia, impairment of clotting factors
4. volume resuscitation, correct coagulopathy, splanchnic vasoconstriction (decrease blood flow to intestine, stomach, collaterals); VASOPRESSIN, SOMATOSTATIN (blocks vasodilators like Glucagon)
MAJOR CAUSE of DEATH in liver disease
Tx of variceal hemorrhage
- endoscopic therapy to sclerose or band varices
- decrease portal pressure: Beta blockers, portosystemic shunt (surgical or transjugular intrahepatic), liver transplant
What causes ascites (3 pathways)?
- increased resistance to portal venous flow, increased flow to portal vein, increased lymphatic flow, leakage of lymphatic flow from the liver and intestines
- increased portosystemic shunting of vasodilators, systemic vasodilation
- decreased renal perfusion, increased renal vasoconstriction, increased Renin-Angiotensin, increased Na reabsorption
Hypotheses of Ascites
- traditional underfill concept
- overflow hypothesis
- revised underfill theory
- ascites formation, decreased effective volume, renal Na retention, ascites and edema
- primary renal tubular retention of Na, increase plasma volume, translocation of fluid out of splanchnic circulation as ascites
- primary peripheral vasodilation, imbalance of capacitance and volume (relative underfilling), renal Na retention
complications of ascites
- tense ascites: pressure on diaphragms and stomach, difficulty breathing and eating
- hepatic hydrothorax
- spontaneous bacterial peritonitis
- spontaneous bacterial peritonitis
spontaneous bacterial peritonitis
due to ascites (therefore liver disease)
- large amount of undrained fluid, low protein and complement
- bacterial translocation from intestines to blood, bacteremia infects ascites
Tx of ascites
- Na restriction
- diuretics
- Tx the underlying liver disease
- large volume paracentesis
correct portal HTN
other: transjugular/surgical portosystemic shunt, liver transplant
Two important effects of portal HTN
- ascites
2. varices
normal serum lab values
- ALT, AST, GGT
- ALP
- 10-60 U/L
2. 45-150 U/L
normal serum lab values
albumin
3.5-5.2 g/dL
normal serum lab values
alpha-1 antitrypsin
100-200 mg/dL
normal serum lab values
ammonia
7-27 micromol/L
normal serum lab values
amylase
30-110 U/L
normal serum lab values
bilirubin (total)
0.2-1.9 mg/dL
normal serum lab values
ceruloplasmin
25-63 mg/dL
normal serum lab values
copper
26-190 mcrgm/dL
normal serum lab values
creatinine
0.7-1.4 mg/dL
What population has a very high prevalence of alcoholic liver disease?
Native American
stages of alcoholic liver disease
- steatosis
- alcoholic hepatitis
- alcoholic cirrhosis
What can liver cirrhosis lead to?
- hepatocellular carcinoma
2. cholangiocarcinoma
How many drinks/day for alcoholic liver disease and how many years?
5 yrs
men: more than 6 drinks
women: 3 drinks
Why do women require less drinking than men to get alcoholic liver disease?
- differences in volume of distribution
- decreased alcohol dehydrogenase activity
- differences in first pass metabolism
alcoholic hepatitis
40-60 yrs old
Sx: jaundice, muscle wasting, ascites, tender hepatomegaly, FEVER
AST over 2x ALT (both are rarely over 300)
also: elevated INR, leukocytosis
normal prothrombin time (PT)
10.7-15 s
normal INR
below 1.1
2-3 if on warfarin
ADH2*1 polymorphism
East Asian
increased susceptibility to alcoholic liver disease (flushing due to acetaldehyde build up)
TNF a-238 polymorphism
Caucasians
increased susceptibility to alcoholic liver disease
Mechanism of ALD pathogenesis
- ethanol, acetylaldehyde cause intestinal injury and increased permeability
- results in endotoxemia
- results in inflammatory response by Kupffer cells
Two hit theory of ALD
Hit 1: Fatty Liver: oxidative stress, increased NADH/NAD ratio, obesity/DM
fat sensitizes liver to 2nd hit
Hit 2: inflammation and necrosis; oxidative stress/hypoxia/immunological rxn
Maddrey score
modified discriminant function: predictor of survival in ALD
[4. 6 (PT- control)] + bilirubin
greater than 32: one month mortality is 1/3 to 1/2
Glasgow Alcoholic Hepatitis Score
score: 1, 2, 3
predictor of survival in ALD
greater than 9: bad
1. age: less than 50, greater than 50; no 3 score
2. WBC: less than 15,000, more than 15,000; no 3 score
3. BUN: less than 14, more than 14; no 3 score
4. INR: less than 1.5, 1.5-2, greater than 2
5. bilirubin: less than 7.4, 7.4-14.7, more than 14.7
C282Y mutation
location: HFE gene
missense: Cys to Tyr
hemochromatosis
decreased sensing of iron stores leads to excess iron absorption in intestine
decreases hepcidin
HFE gene
type I hemochromatosis
defect: can’t sense iron: absorb iron you don’t need
ALD patients with C282Y mutations had?
increased hepatic iron scores
higher rates of HCC
MZ or SZ
heterozygous
alpha-1 antitrypsin deficiency
ZZ
homozygous
alpha-1 antitrypsin deficiency
most important environmental factors in determining ALD risk
ethanol pattern
obesity and hyperglycemia