10/21- Liver failure and portal HTN Flashcards
What is seen here?
Normal liver (left) vs. cirrhosis (right)
Non-invasive alternatives to liver biopsies?
- Fibroscan
- Magnetic Resonance Elastography (MRE)
Describe Fibroscan
- Pros/cons
Fibroscan
- Works best on thin patients
- Tells you how stiff/soft the liver is (stiffness can indicated cirrhosis)
What do these fibroscan results show?
- Not as steep slope on left (stiffer?)
- Steep slope on right (softer?)
How do liver diseases compare on fibroscan results (grades of stiffness)?
Different diseases cause different fibrotic patterns and different densities. Also happen at different times
Describe Magnetic Resonance Elastography (MRE)
Again, indicates stiffness (blue -> red scale)
- Newer technique
- Good for saying yes/no to cirrhosis
What are the 3 types of liver decompensation?
- Synthetic failure
- Portal HTN
- Hepatocellular Carcinoma (HCC)
What are markers of synthetic failure in terms of liver disease (what symptoms do you see)?
Synthetic Failure
- Jaundice
- Prolonged INR (low clotting factors)
- Hypoalbuminemia
What are signs/symptoms of portal hypertension?
Portal vein entering the base of the liver; dilates; 3x increase in pressure (4->12 mmHg)
- Hypersplenism
- Fluid retention
- Ascites and peripheral edema
- Varices
- With/without bleeding
- Encephalopathy
What are the cardinal signs of liver failure?
If you have any of these, you have liver failure.
Mortality goes up significantly once any of these happen
- Jaundice
- Ascites
- May include SBP
- May include peripheral edema
- Variceal bleed
- Encephalopathy
- Clinical or subclinical
Other signs of liver failure?
- Spider angiomata
- Fed from the middle (blanching)
- Surprisingly common in people with cirrhosis (especially alcoholic)
- Palmar erythema
- Dupuytren contracture
Describe bilirubin synthesis
- RBCs -> hemoglobin -> globin + heme
- Heme is degraded into bilirubin (unconjugated); carried with albumin to liver
- Bilirubin transported into hepatocyte and binds Ligandin
- Glucuronidation -> conjugated bilirubin
- Bilirubin conjugation actually involves clevage site, heme oxygenase conversion into Biliverdin, and then conjugated bilirubin
- Bile excreted into bile duct In the intestine:
- Bilirubin glucuronide (conjugated) converted back into bilirubin (unconjugated) by gut bacteria
- Bilirubin converted into urobilinogen/urobilin
- Urobilin should be reabsorbed and sent to kidney (yellow color of urine)
- Urobilinogen converted to stercobilin and excreted by gut (brown color of stool)
**There is no bilirubin in urine or stool!
What are causes of high unconjugated (indirect) bilirubin?
Excess bilirubin production
- Hemolysis
Failure of conjugation (typ hereditary)
- Gilbert syndrome
- Neonatal jaundice
- Crigler-Najjar
(Other lecture also mentioned decreased uptake such as with Rifampin)
What are causes of high conjugated (direct) bilirubin?
- Biliary obstruction
- Liver damage
- Failed excretion
- Dubin-Johnson
- Rotor
(Other lecture separated this into main liver disease or obstructive causes; important here to also add failed excretion)
How is clinical testing for direct vs. indirect bilirubin done?
Uses a color assay (diazo)
- Conjugated bilirubin is soluble and direct-reacting
- Unconjugated bilirubin is not soluble and only reacts after alcohol is added
After initial and then alcohol stages, the total amount has reacted
- Indirect is calculated by subtracting direct from total
- A small amount of unconjugated reacts without alcohol (5-10% of total), so direct levels might be a tad high
- Normal unconjugated levels are 0, but will get a low amount using this assay
What is cholestasis?
Failure of bile excretion
What are effects of cholestasis?
- Bile contents in the circulation
- Bilirubin -> jaundice
- Bile salts -> pruritis
- Hepatocyte effects
- Obstruction -> alkaline phosphatase
- Damage -> ALT and AST
- Malabsorption of fats and fat-soluble vitamins
- Absence of stercobilin in stool (clay-colored) and urobilin in urine (colored instead by bilirubin, darker?)
Look at these pictures of dilated bile ducts due to obstruction
What is shown here?
ERCP
- Large duct obstruction
- Can see stone and dilated duct leading into liver
What is seen here? Main features?
Normal liver histology
- Portal tract (triad)
- Terminal hepatic venule
- Zones 1-2-3 moving from tract -> venule
What are diseases of small duct obstruction
- Primary biliary cirrhosis (aka non-suppurative
- Primary sclerosing cholangitis
What happens in primary biliary cirrhosis?
- PBC – cells and lymphocytes destroy bile duct
- Granulomas
What happens in primary sclerosing cholangitis?
- Primary sclerosing cholangitis
- Bead signs (dilated and strictured areas
- Thick onion-skin appearance of fibrous tissue obstruction the duct
What is seen here?
Primary biliary cirrhosis
- PBC – cells and lymphocytes destroy bile duct
- Granulomas
What is seen here?
- Primary sclerosing cholangitis
- Bead signs (dilated and strictured areas
- Thick onion-skin appearance of fibrous tissue obstruction the duct
What is seen here?
- Primary sclerosing cholangitis
- Bead signs (dilated and strictured areas
- Thick onion-skin appearance of fibrous tissue obstruction the duct
Look at these key anatomic features of the liver
- Hepatic vein: entering superiorly
- Sinusoid
- Portal vein: entering base of the liver
- Coronary vein: comes int quite high off of the liver
- Splenic vein
What happens vascularly in cirrhosis (think of key anatomic features just mentioned)
Portal HTN- result of increased portal venous inflow and sinusoidal resistance
- Splanchnic vasodilation and increased flow into mesenteric veins (leading to:)
- Increased flow into portal vein
- Distorted sinusoidal architecture -> increased resistance
What is the pathophysiology of ascites and HRS (hepato-renal syndrome)?
- Cirrhosis causes portal HTN and NO overproduction
- NO overproduction causes splanchnic and arterial vasodilation
- This splanchnic arterial vasodilation results in both (1) decreased effective BV and (2) splanchnic lymph production
- Decreased effective blood volume stimulates ADH production, Sympathetic nervous system activation, and the RAAS system
- All of these cause (1) sodium/water retention and (2) decreased renal blood flow
- Ascites results from this sodium/water retention (from decreased effective blood volume) and splanchnic lymph production (both of these are a result of splanchnic and arterial vasodilation)
- HRS results from decreased renal blood flow
What causes hyponatremia?
- Cirrhosis is the leading cause of ____
- Indication of outcomes
- Associations
- Treatment
NOT a shortage of salt
Cirrhosis is the leading causes of dilutional (hypervolemic) hyponatremia
- Water retention exceeds Na retention
- Complications and outcomes are worse in pts with hyponatremia
- May be associated with diuretics
- Treated with WATER restriction
What sign/symptom is a big turning point?
- Prognosis?
Ascites
- 50% mortality at 2 yrs
What causes ascites?
- Complications
- Treatment
- Requires 10 mm transhepatic pressure gradient
- May be infected- spontaneous bacterial peritonitis (SBP)
Treatment: paracentesis
- Direct aspiration of fluid
- Bleeding is not related to coagulopathy
- Fluid shift after paracentesis