B58, Circulatory disorders of the liver

Question 1

Describe the epidemiology of liver infarcts.

What kind of infarction is it?

Answer 1

Very rare, due to the dual blood supply, requires impairments of both circulations.

Except in trasnplant cases, where occlusion of jsut the hepatic artery causes organ death.

Small infarcts can occur due to occlusion of intrahepatic branches of the artery, caused by polyarteritis nodosa, neoplasia, sepsis, or embolii.

Hemorrhagic infarct.

Question 2

What are the possible causes of portal vein obstruction?

Answer 2

• Peritoneal sepsis and phlebitis of the portal vein
• Pancreatitis causing a splenic vein thrombosis that moves to the portal ein
• Hypercoagulable states and post surgical thrombosis
• Vascular invasion of hepatic cancers to the portal vein
• Banti syndrome, a long-standing portal thrombosis that has been canalized
• Cirrhosis

Question 3

What are the consequences of acute vs chronic portal vein obstruction?

Answer 3

Acute thrombosis will cause congestion and infarction of the bowels.

Chronic obstruction leads to portal hypertension, ascites, splenomegaly and hypersplenism.

Question 4

What are the causes and consequences of impaired intrahepatic blood flow?

Answer 4

Causes:

• Cirrhosis
• Sinusoid occlusion syndrome
• Right heart failure
• Sickle cell disease
• DIC

Consequences:

• Ascites
• Portal hypertension
• Hepatomegaly

Question 5

What are the causes of impaired hepatic vein flow (liver outflow)

Answer 5

Budd Chiari syndrome, hepatic veinous thrombosis, in at least 2 of the major hepatic veins. Seen primarily in Polycytemia Vera and Paroxysmal Noctournal Hemoglobinuria.

Fatal, needs to be treated, with surgical creation of portal-systemic shunts, allowing systemic blood flow to move into portal system and supply the liver.

Sinusoidal obstructive syndrome: After a drug or toxin insult, damaged sinusoidal epithelial cells die and slough into the sinusoids causing obstruction. Can be fatal. Hepatomegaly, jaundice, ascites, actue liver failure.

Question 6

What are the major hypercoagulable states?

Answer 6

Congenital

• Leiden mutation of factor 8
• Antithrombin 3 deficiency
• Protein C or S deficiency
• Prothrombin 20210A mutation, increased levels of prothrombin

Acquired (C-PIANO)

• Cancer
• Pregnancy
• Injury/Surgery
• Age
• Nephrotic syndrome
• Oral contraceptives