Portal Hypertension

Question 1

What is portal hypertension?

Answer 1

Increase in blood pressure in the hepatic portal system (portal venous system)

Question 2

What causes portal hypertension?

Answer 2

Most commonly hepatic cirrhosis

Question 3

What veins are involved in the portal venous system?

Answer 3

1. Portal vein
2. Splenic vein
3. Mesenteric vein

Question 4

What is special about the portal venous system?

Answer 4

The blood contains all the nutrients absorbed by the GI tract also carries toxins that the liver metabolises so that they can safely excreted by the kidneys.

Question 5

What happens to the blood once it leaves the portal venous system?

Answer 5

It is then sent to the heart via the IVC and enters the systemic venous system

Question 6

At what different points is the hepatic portal vein connected to the systemic venous system?

Answer 6

1. The inferior portion of the oesophagus
2. The superior portion of the anal canal
3. The round ligament (umbilical vein embryonically)

Question 7

What is the pressure in the venous system?

Answer 7

<12mmHg

Question 8

What is the definition of portal hypertension?

Answer 8

When the pressure in the hepatic portal system rises above 12mmHg

Question 9

What causes a rise in pressure in the hepatic portal system?

Answer 9

Obstruction that prevents the flow of blood from the portal vein to the IVC causing venous blood to accumulate in the portal system.

Question 10

What happens as a result of portal hypertension?

Answer 10

You get the formation of portosystemic shunts - where blood is diverted away from the portal system and backs up into the systemic veins. This happens in the 3 places that the systemic and portal system are connected.

Question 11

What are the consequences of a reduction of blood flow to the liver?

Answer 11

This causes a decrease in liver function, therefore a decrease in blood detoxification leading to a build up of toxic metabolites such as ammonia

Question 12

How does hepatic encephalopathy occur?

Answer 12

Ammonia and other toxic metabolites can pass through the blood brain barrier and cause hepatic enecephalopathy

Question 13

What happens to the oesophagus in portal hypertension?

Answer 13

The veins in the oesophagus enlarge causing oesophageal varices (portal hypertension the most common cause). These veins are fragile and can easily rupture causing a massive upper GI bleed.

Question 14

What happens to the anus/rectum in portal hypertension?

Answer 14

You can get hemarrhoids which are enlarged veins that may bleed.

Question 15

How does portal hypertension cause caput medusa?

Answer 15

Portal hypertension causes the round ligament to re-channel blood from the portal system –> abdominal veins –> causing vein dilation –> caput medusa

Question 16

What is hyperslenism and how does portal hypertension cause it?

Answer 16

Hyperslenism is an enlarged spleen that causes the trapping of RBCs, WBCs and platelets leading to anaemia, leukopenia and thrombocytopenia.

It is caused by blood backing up into the spleen.

Question 17

What happens to endothelial cells in portal hypertension?

Answer 17

Endothelial cells release NO, which dilates arteries and decreases BP. Fluid is then pushed across tissues into the peritoneal cavity to form ascites. Which can lead to spontaneous bacterial perotinitis.

Question 18

What are the features of portal hypertension?

Answer 18

A - ascites 
B - bleeding 
C - caput medusae 
D - diminished liver function 
E - enlarged spleen

Question 19

How can the causes of portal hypertension be classified?

Answer 19

1. Pre-hepatic
2. Intra hepatic
3. Post hepatic

depending where the obstruction is

Question 20

What are the causes of portal hypertension?

Answer 20

1. Pre-hepatic obstruction by a thrombus occluding the portal vein
2. intra-hepatic: cirrhosis (most common) or schistosomiasis (when flatworms invade the liver) or sarcoidosis (when inflammatory cells form granulomas)
3. Post-hepatic: Right sided heart failure, constrictive pericarditis and Budd-Chiari syndrome

Question 21

Signs of Portal hypertension?

Answer 21

• distended abdomen (ascites)
• caput medusae
• GI bleeding (secondary to oesophageal varices)
• hematemesis
• melana or heamtochezia
• Jaundice (liver impairment)
• Asterixis, altered consciousness, lethargy, seizure or coma (hepatic enecphalopathy)

Question 22

Investigation of portal hypertension?

Answer 22

1. Gold standard - Hepatic venous pressure gradient measurement - catheter in IVC and portal vein to measure the difference between both pressures
2. Liver ultrasounds - nodules in cirrhosis
3. CT scan/MRI for ascites, cirrhosis, splenomegaly or vascular alterations - IVC dilatation.
4. FBC, Liver enzymes and serology for cause
5. upper GI endoscopy for oesophageal varices.

Question 23

Treatment of portal hypertension?

Answer 23

1. Beta-blockers - propranolol to decrease portal venous pressure and prevent complications.
2. ascites - sodium restriction and diuretics to reduce fluid overload.
3. bleeding oesophageal varicies - Octreotide and baloon tamponade, sclerotherapy, variceal ligation
4. Bleeding prevention - interventional radiology, procedure to reduce portal pressure. prevent complications
   TIPS - tube inserted via catheter to allow communication between portal vein and hepatic vein.