16. Hepatic physiology Flashcards
Liver characteristics
600-800g
80% from celiac plexus, rest SMA
C.O. 25%
75% blood flow from portal vein
Zones of liver
- Zone 3 more distant to the artery, more sensible to ischemia. Glycolysis
Phases of liver metabolism
- Oxidation, reduction, hydrolysis. Inducer Phenytoin
- Conjugation. Mainly gluconization
Primary sclerosing cholangitis
Woman 30 / 40
Typical with U.C.
inflammation and fibrosis of the bile ducts
Liver transplantation is the only effective therapy.
TIPS indication
Increase portal pressure
Prevent encephalopathy
Ascitis
Bleeding from medula
Pringle maneuver
Block of hepatic artery / portal vein
Factors sensitize in the liver
fibrinogen, prothrombin, factor V, VII, IX, X, XI, XII, as well as protein C and S, and antithrombin
Gilberts syndrome
Asymptomatic unconjugated hyperbilirubinemia
Hepatorenal syndrome
Kidney failure in patients with cirrhosis. Dx. creat x 2 in two weeks
40% patients with ESLD
No responsiveness to fluids
Dialysis from prevention
No treatment (only transplant)
type I fast
Type 2 slow
West raving rating for encephalopathy
- Changes only in mood
- Mood + performance + Lethargy/apathy
- Somnolence, apathy
- Coma
In acute liver injury, what’s first
Increase in PT, after changes in albumin
Child pugh score
Primary biliary cirrhosis
90% woman, 60 years old
Autoimmune disease, due to decrease tolerance to mitochondrial antigens.
At diagnosis tiredness and itching
Treatment consists of ursodeoxycholic acid (UDCA)
Raynaud phenomenon
CYP3A inh
Saquinavir
Bile
400-600 ml day
95% water
Reabsorption in terminal ileum
participated in the elimination of toxins
Half life of albumin
20 days
What is the half-life of coagulation factor VII?
4 hours
The earliest laboratory sign in blood tests for liver cirrhosis
Thrombocytopenia
Kupffer cells are
resident hepatic macrophages and found in the sinusoids.
CYP3A inducers
Phenytoin, rifampin, St. John’s wort, efavirenz, etravirine, nafcillin, prednisone
Heme group in the liver
10% 90% bone marrow
Not dependent on iron
For Cytokine p450
Deficiency en synthesis leads to porphyria
Porphyria
The most common porphyria is
acute intermittent porphyria, It is caused by a deficiency in porphobilinogen deaminase
Hyponatremia in 40%. Sensitivity to the sun
AST and ALT
ALT is mainly a cytoplasmic liver enzyme.
In contrast, cytoplasmic and mitochondrial
isozymes of AST are found in many extrahepatic tissues
AST/ALT elevated in Wilson/alchoholic
Lactate Dehydrogenase
Lactate dehydrogenase (LDH) is a nonspecific marker of hepatocellular injury. Extremely elevated LDH signifies massive hepatocyte damage, usually from ischemia or drug-induced hepatotoxicity (such as acetaminophen overdose)
Albumin and prelalbumin
Prealbumin is another protein synthesized in
the liver that is also involved in transport and binding. It has a much shorter half-life than albumin (20 days).
The level of prealbumin reflects the status of protein nutrition
Factor 7 1/2 life
fibrinogen
4 hours
4 days
Gold standard for HCV
Antibodies HCV
Main reason for death in liver cirrhosis
Portal hypertension
Decompensated cirrhosis
Ascitis + bleeding + Encephalopathy
Portal hypertension characteristics
Portal hypertension is defined as a hepatic venous pressure gradient (HVPG) greater than 5mm Hg.
Patients with an HVPG greater than 10 mm Hg
are deemed to have clinically significant portal hypertension.
Tx. nonspecific beta-blockers (i.e., propranolol, timolol), carvedilol or endoscopic variceal ligation to prevent variceal hemorrhage.
Hepatitis B and cirrhosis
Not connected
Beta blockers and portal hypertension
Decrease HVPG (hepatic venous portal gradient)
After hepatic resection, values come back to normal…
INR POD 1-2
Ptl lowest POD 3-4
Return to baseline POD 4-5
