Flashcards in Portal HTN and Ascites Deck (21)
Two blood supplies to the liver are?
Hepatic artery (30%)
Portal vein (70%)
Influence of Cirrhosis on blood flow thorugh the liver?
Cirrhosis causes fibrosis with distortion of the vasculature. Sinusoids turn into capillaries. You get increased blood flow to the stomach and intestines
During portal hypertension, venous collaterals form from teh distal esophagus to where
Anterior collaterals form via which vein?
Posterior collaterals form via what veins?
Retroperitoneal, you get splenorenal shunts.
What is a varice?
Varices are tortuous venous collaterals under high pressure
treatment of variceal bleeds
- Volume replacement
- Correct the coagulopathy
- Vasoconstriction of the splanchnic vessels
- decrease blood flow to the stomach and intestines as much as possible
- decrease blood flow via the collaterals
What is the classic triad of bad variceal bleeds
1) High Pressure Bleeding
2) Thrombocytopenia- low plateletts
3) Coagulopathy- synthetic impairment of clotting factors
Mechanism of ascites
- Increased resistance to portal venous flow
- Increased flow to the portal vein because of the increased flow to stomach and intestine from the arterial side due to vasodilators being where they shouldnt
- Increased lymphatic flow
- LEAKAGE of lymphatic flow from the liver and intestines into peritoneal space (liters of fluid)
- Increased portosystemic shunting of vasodilators leads to increased systemic vasodilation
Systemic vasodilation leads to
low blood pressure....kidneys are not perfused
When the kidneys are not perfused how do they react?
Increased vasoconstriction in the kidneys
Increased Renin- ANgiotensin- Aldosterone leading to sodium reabsorption and water holding
The pattern, starting with ascites is
Ascites forms when you get too much blood backed up in the portal vein and lymph system and fluid begins to leak out into the peritoneum---> Shunting of blood away from the portal system brings vasodilators out into systemic circulation where they are not supposed to be --> You get total body hypoperfusion---> Kidneys react by increasing fluid retention through RAAS---> this worsens ascites and leads to edema
Ascites has what effect on kidney function
Decreased renal clearance
Increased sodium retention
Decreased creatinine clearance
Know...Ascites can cause so much pressure in the peritoneum that you have difficulty breathing and eating due to pressure on the stomach and diaphragm
Fluid can get out of the abdomen, past the diaphragm, and into pleural space which can give you
Any fluid that is undrained can get infected.
Gram negative can get into the peritoneal fluid and cause massive infection. This is an emergency
Treatment of ascites
- sodium restriction
- Treat the liver disease
- Large volume paracentesis
So, Chronic portal hypertension causes an increased transvascular pressure gradient between the portal system and the systemic circulation (b/w the portal vein and the hepatic vein). This blood has to get back to the heart though so it will take the path of least resistance,,, portosystemic shunting occurs. As this occurs, vasodilators that our body generally doesn't see because they are confined to the splanchnic circulation, enter the systemic circulation. This leads to increased blood flow to the splanchnic system arteries yet still tons of resistance on the venous side.
Remember, what causes the portal hypertension?
The Cirrhosis of the liver
Decrease the risk of variceal bleed by lowering the bloodflow to the splanchnics