Portal Hypertension (Module 3)

What is portal hypertension?

Increased pressure in the portal vein system

What is the most common PV pathology?

PV hypertension

TRUE or FALSE: Hepatic carcinoma accounts for 90% of the causes of PH in the western hemisphere.

FALSE: Hepatic CIRRHOSIS accounts for 90% of the causes og PH in the western hemisphere.

What type of flow do PV normally exhibit?

Hepatopetal Flow: Blood flow towards the liver via portal veins.

How big is the MPV at porta hepatis?

1.3 cm at porta hepatis.

What are the tributaries to the MPV? (HINT: 4)

- SMV

- Splenic vein

- Pyloric vein (right gastric vein)

- Coronary vein (left gastric vein)

What is the pathophysiology of PV hypertension? (HINT: 3)

- Increased pressure in PV system

- Blood will try to shunt to systemic circulation and caudate lobe to relieve pressure on portal system (caudate enlargement)

- Collaterals may develop to decrease the pressure

What are the categories and subcategories for the causes of PV hypertension?

1. Presinusoidal: pressure within the HVs are normal

- extrahepatic

- intrahepatic

2. True intrahepatic: increased pressure in HVs

3. Posthepatic

What is presinusoidal extrahepatic portal hypertension?

- Thrombosis of splenic vein or PV causing increased pressure in PV system

- Liver is normal (therefore, prehepatic cause)

What is presinusoidal intrahepatic portal hypertension?

Increased PV pressure due to abnormal liver for various reasons:

- Diseases affecting portal zones of liver (schistosomiasis - parasite)

- Primary biliary cirrhosis, congenital hepatic fibrosis

- Fibrosis in portal zone

What is true intrahepatic portal hypertension?

Increased PV pressure due to cirrhosis or diffuse mets to the liver (abnormal liver)

TRUE or FALSE: Presinusoidal intrahepatic causes of PV hypertension involve an abnormal liver.

TRUE: The PV system has increased pressure due to various abnormalities of the liver. Presinusoidal EXTRAhepatic causes have a normal liver.

What is posthepatic portal hypertension?

Increased PV pressure due to extrahepatic obstruction to portal outflow (ex. CHF, Budd-Chiari)

- Liver congested with blood (cardiac liver)

- Progressive

What are the differences between initial and late stages of cardiac liver (posthepatic cause of PV hypertension)?

Initial (acute passive congestion):

- enlarged liver

- distended hepatic veins

Late (chronic passive congestion):

- cardiac cirrhosis (HVs compressed from liver parenchyma)

Name 3 symptoms/signs for the clinical presentation of portal hypertension.

- Jaundice

- GI bleeding: thin walled veins rupture

- Ascites

- Splenomegaly

- Varices: torturous dilated veins

- Hepatic failure

- Hepatic encephalopathy: inability to remove toxins from blood, causing toxins to enter brain and reduce cognitive function

What are direct sonographic appearances of portal hypertension? (HINT: 2)

1. Increased size of extraheptic portals

2. Hepatofugal flow (PV take blood away from liver = abnormal)

- LPV to paraumbilical vein (ligamentum teres)

- MPV

What are indirect sonographic appearances of portal hypertension? (HINT: 5)

- Splenomegaly

- Varices (postsystemic venous collaterals)

- Ascities

- Caudate lobe enlargement

- Cirrhotic liver

The body makes collaterals to shunt PV blood to systemic circulation to relieve the pressure in the PV system. What are the complications with this?

If blood is avoiding the PV system, blood is no longer going to liver, meaning that toxins remain in the blood, which could result in encephalopathy or death.

What are the 5 main collateral sites imaged in U/S for portal hypertension?

1. GEJ: coronary vein (more than 7mm = severe PH)

2. Paraumbilical vein (opens to send blood from LPV --> umblicus)

3. Splenorenal/gastrorenal vein

4. Intestinal

5. Hemorrhoidal

What is hepatofugal flow?

- Reversed flow where the PVs are now taking blood AWAY from the liver

- Causes paraumbilical vein to recanalize from the increased PV pressure (more than 3mm = severe PH, caput medusa)

What are esophageal varices?

Dilated veins in the esophagus from portal decompression via coronary vein

(many chronic liver disease patients die from bleeding esophageal varices)

What is caput medusa? What causes this appearance?

- Distended superficial abdominal veins resembling a medusa

- During PH, blood exhibits hepatofugal flow, going from the liver to the umbilicus, resulting distended veins near the umbilicus

How does splenomegaly occur from PH?

- Spleen is reservoir for blood

- Splenic vein is distended as blood backs up into the spleen, causing mild splenomegaly (12-14cm length)

What are the 2 types of portovenous shunts?

1. Spontaneous: collateral circulation forms (varices)

2. Surgery (complications of bleeding if pt isn't ideal candidate)

- Portocaval: MPV --> IVC

- Mesocaval: SMV --> IVC

- Splenorenal: splenic vein --> IVC

What is a TIPS procedure? How is it done?

Transjugular intrahepatic portosystemic shunt procedure

- Relieves varices with GI bleeding

- Transjugualr approach where tubular stent placed in liver parenchyma

- Communication b/w one branch of PV and one branch of HV established