Hepatology - Vascular liver diseases Flashcards
What causes hepatic arterial disease?
Ischaemia can be due to hypoperfusion (as occurs during hypotensive or hypoxic events) or due to arterial occlusion. The latter may result from inadvertent injury during biliary surgery or may be caused by emboli, neoplasms, PAN, blunt trauma or radiation. It usually causes severe upper abdominal pain with or without circulatory shock. LFTs show high transaminase activity. Patients usually survive if the liver and portal blood supply are otherwise normal.
What causes portal venous thrombosis and how does it present?
Portal venous thrombosis is rare but can occur in any prothrombotic condition. Acute portal venous thrombosis causes abdominal pain and diarrhoea, and may lead to bowel infarction, requiring surgery. Patients need anticoagulation and investigation for underlying thrombophilia. Subacute thrombosis can be asympatomatic but may lead to extrahepatic portal hypertension later on.
Important conditions related to portal hypertension include the hepatopulmonary and portopulmonary syndromes.
What is hepatopulmonary syndrome?
In this condition, patients with cirrhosis and portal hypertension develop resistant hypoxaemia (PaO2 <9.3) due to intrapulmonary shunting through direct arteriovenous communications. Clinical features include finger clubbin, spider naevi, cirrhosis, and a fall in SaO2 on standing. It resolves following liver transplantation.
What is the portopulmonary hypertension?
This is defined as pulmonary hypertension in a patient with portal hypertension. It is caused by vasoconstriction and obliteration of the pulmonary arterial system and presents with breathlessness and fatigue.
What can cause hepatic venous disease?
Obstruction to hepatic venous blood flow can occur in the small central hepatic veins, the large hepatic veins, the inferior vena cava or the heart.
3 main conditions are considered:
1) Budd-Chiari syndrome
2) Veno-occlusive disease
3) Cardiac disease
What is Budd-Chiari syndrome?
This is an uncommon condition.
It is characterised by thrombosis of the larger hepatic veins and sometimes the IVC. The cause cannot be found in about 50% of patients. Some have haematological disorders such as myelofibrosis, antiphospholipid syndrome, primary polycythaemia, paroxysmal nocturnal haemoglobinuria, and antithrombin III, protein C or protein S deficiency.
What are the clinical features of Budd-Chiari syndrome?
Sudden venous occlusion causes the rapid development of upper abdominal pain, marked ascites and occasionally acute liver failure. More gradual occlusion causes gross ascites and often upper abdom- inal discomfort. Hepatomegaly, often with tenderness over the liver, is almost always present. Hepatic congestion affecting the centri- lobular areas is followed by centrilobular fibrosis, and eventually cirrhosis in those who survive long enough.
How is Budd-Chiari investigated?
Doppler US is the initial investigation of choice. This will show abnormal flow in the major hepatic veins or inferior vena cava and thickening, tortuosity, and dilatation of the walls of the hepatic veins. Non-specific findings include hepatomegaly, splenomegaly, ascites and caudate lobe hypertrophy. CT or MRI may demonstrate abnormalities of the hepatic veins if the US is normal and clinical suspicion is high. Liver biopsy is not usually necessary to make the diagnosis but will show centrizonal congestion, necrosis and haemorrhage.
LFTs can vary depending on the presentation.
Ascitic fluid analysis typically shows a protein concentration of >25g/L (exudative) in the early stages.
What is the management of Budd-Chiari?
Underlying conditions should be treated.
Underlying haematological condition should be treated (e.g. anticoagulation)
BCS associated with chronic inferior vena caval thrombosis has been treated safely with warfarin.
Ascites should be managed with diuretics (spironolactone is first-line, followed by furosemide and chlorothiazide) plus fluid and salt restriction.
Local thrombolysis with radiological support is preferred to generalised thrombolysis.
Surgical decompression of liver is performed in cases of persistent congestion (eg, via transjugular intrahepatic portosystemic shunt (TIPS)) and gives excellent results, even in high-risk patients. Other shunts sometimes tried include mesocaval, mesoatrial and portocaval.
What is veno-occlusive disease?
Widespread occlusion of central hepatic veins is the characteristic of this rare condition. Pyrrolizidine alkaloids in Senecio and Helio- tropium plants used to make teas, cytotoxic drugs and hepatic irra- diation are all recognised causes. The clinical features are similar to those of the Budd–Chiari syndrome.
How does cardiac disease affect the heart?
Hepatic damage due primarily to congestion may develop in all forms of right heart failure; the clinical features are predomi- nately cardiac. Very rarely, long-standing cardiac failure and hepatic congestion cause cardiac cirrhosis.
