| 18. Vascular
Disorders of the Liver / L.J. Worobetz |
page
555 |
The most frequent
abnormality of circulation to affect the liver is congestive heart
failure, which leads to reduced outflow of blood from the liver. Other
causes of hepatic congestion include constrictive pericarditis,
obstruction of the inferior vena cava and hepatic veins (Budd-Chiari
syndrome) and occlusion of the small hepatic veins (veno-occlusive
disease). Increased resistance to hepatic venous outflow results in
congestive hepatomegaly, dilation of hepatic venules and sinusoids, and
hypoxia. The hypoxia in turn leads to hepatocyte damage with possible
fibrosis and cirrhosis, the latter termed cardiac cirrhosis.
| 18.1 Congestive
Heart Failure |
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555 |
The clinical features of
congestive heart failure include tender hepatomegaly and abdominal
discomfort. In tricuspid insufficiency, the liver may be pulsatile.
Ascites, which may be present, often involves exudate with a high protein
content. Characteristic biochemical abnormalities are mild
hyperbilirubinemia with a moderate elevation of aminotransferases
(<300) and a mild elevation of alkaline phosphatase, especially in
acute congestion. In ischemic liver damage, aminotransferase can be quite
high (from the necrosis), simulating hepatitis - hence the term ischemic
hepatitis. The prognosis is directly related to the severity and the
response to therapy of the underlying heart failure.
| 18.2 Hepatic Vein
Thrombosis (Budd-Chiari Syndrome) |
page
556 |
Hepatic vein thrombosis
is a rare disorder that may occur alone or in association with inferior
vena cava thrombosis. It may be associated with polycythemia vera,
paroxysmal nocturnal hemoglobinuria, hypercoagulability, use of oral
contraceptives or neoplasia, or it may be secondary to obstruction by a
membranous web. The presentation may be acute, with rapidly developing
hepatomegaly, ascites, and abdominal pain leading to liver failure and
coma. The chronic presentation is usually that of progressive ascites.
The degree of aminotransferase elevation is variable, depending on the
rapidity of the onset. The liver biopsy shows large hemorrhagic areas
with congestion, atrophy and necrosis around the center of the lobule.
Diagnosis may be assisted by liver- spleen colloid scan showing
decreased uptake in areas that are otherwise normally drained by the
hepatic vein. The caudate lobe demonstrates a normal uptake in that it
has a different drainage, that being directly into the vena cava.
Hepatic vein Doppler studies clarify the impaired venous blood flow. The
conclusive study is IVC hepatic venography revealing blocked hepatic
veins. Assuming absence of a correctable lesion such as a membranous
web, treatment by anticoagulants and streptokinase is rarely successful.
With acute thrombosis, most patients die of liver failure and hepatic
coma. Occasionally helpful is a portacaval or mesocaval shunt to allow
decompression.
| 18.3 Veno-occlusive
Disease |
page
556 |
Veno-occlusive disease
refers to the obstruction of small and medium-sized intrahepatic veins.
Causal factors include pyrroline alkaloids, hepatic irradiation,
azathioprine and graft-versus-host disease related to bone marrow
transplantation. The presentation mimics the Budd-Chiari syndrome. In
the acute form, presentation may include hepatomegaly, ascites and liver
failure. The chronic form leads to cirrhosis and portal hypertension
with esophageal varices. The liver biopsy characteristically shows
intense congestion around the hepatic venule with thickened obstructive
hepatic veins. There is no effective therapy available. Control of the
ascites may be required. Some patients have a spontaneous recovery,
while others develop cirrhosis with sequelae of portal hypertension,
varices and ascites. Liver transplantation may be the only hope for
many.
| 18.4 Portal Vein
Thrombosis |
page
557 |
Thrombosis of the portal
venous system may result from trauma, pancreatitis, neoplasia (e.g.,
hepatoma), neonatal umbilical sepsis, pylephlebitis or a complication of
cirrhosis, or may be idiopathic. Patients usually present with massive
hematemesis that is recurrent. Splenomegaly is present. Biochemical
tests of the liver are normal or only mildly elevated. Because liver
function is usually normal, ascites and encephalopathy are uncommon and
bleeding episodes are better tolerated. Diagnosis may be confirmed by
special Doppler ultrasound studies of the portal vein, splenoportogram
and/or a venous phase of hepatic angiography. If treatment is required
for recurrent hematemesis from esophageal varices, sclerotherapy may be
necessary. Because of normal liver parenchyma, surgical approaches such
as mesocaval shunt may be considered and are generally better tolerated
than by patients with chronic liver disease. |