Chapter 18 –Circulatory Disorders :HEPATIC VENOUS OUTFLOW OBSTRUCTION Flashcards
HEPATIC VENOUS OUTFLOW OBSTRUCTION
- Hepatic Vein Thrombosis and Inferior Vena Cava Thrombosis
- Sinusoidal Obstruction Syndrome (Veno-Occlusive Disease)
Obstruction of a single main hepatic vein by thrombosis is clinically what?
silent.
What is Budd-Chiari syndrome?
The obstruction of two or more major hepatic veins produces liver enlargement, pain, and ascites, a condition known as Budd-Chiari syndrome.
Hepatic damage is the consequence of increased intrahepatic blood pressure, and an inability of the massive hepatic blood flow to shunt around the blocked outflow tract.
Hepatic vein thrombosis is associated with what diseases?
- primary myeloproliferative disorders (including polycythemia vera),
- inherited disorders of coagulation (e.g., deficiencies in antithrombin, protein S,
- or protein C, or mutations of factor V; see Chapter4 ),
- antiphospholipid syndrome,
- paroxysmal nocturnal hemoglobinuria, and
- intra-abdominal cancers, particularly HCC.
- The occurrence of hepatic vein thrombosis in the setting of pregnancy or oral contraceptive use is usually through interaction with an underlying thrombogenic disorder.
- About 10% of cases are idiopathic in origin, presumably unrecognized thrombogenic disorders.
What is obliterative hepatocavopathy?
A separate distinction is made for inferior vena cava obstruction at its hepatic portion (obliterative hepatocavopathy).
This disorder is caused by inferior vena cava thrombosis or membranous obstruction of the inferior vena cava.
It is endemic in Nepal, with a suspected
association with infections.
What is the gross appearance of Budd-Chiari syndrome?
In the Budd-Chiari syndrome, acutely developing thrombosis of the major hepatic veins or the hepatic portion of the inferior vena cava, the liver is swollen and redpurple and has a tense capsule ( Fig. 18-39 ).
What is the microscopic appearance of Budd-Chiari syndrome?
Microscopically the affected hepatic
parenchyma reveals severe centrilobular congestion and necrosis.
Centrilobular fibrosis develops in instances in which the thrombosis is more slowly developing.
The major veins may
contain totally occlusive fresh thrombi, subtotal occlusion, or, in chronic cases, organized
adherent thrombi.
FIGURE 18-39 Budd-Chiari syndrome
. Thrombosis of the major hepatic veins has caused
extreme blood retention in the liver.
What is the mortality rate of acute hepatic vein thrombosis?
The mortality of untreated acute hepatic vein thrombosis is high.
Prompt surgical creation of a
portosystemic venous shunt permits reverse flow through the portal vein and considerably
improves the prognosis.
In the case of vena caval thrombosis, direct dilation of caval obstruction may be possible during angiography.
The chronic forms of these thrombotic
syndromes are far less lethal, and more than two thirds of patients are alive after 5 years
What is the Sinusoidal Obstruction Syndrome (Veno-Occlusive Disease)?
Originally described in Jamaican drinkers of pyrrolizidine alkaloid–containing bush tea and
named veno-occlusive disease, the disease is now called sinusoidal obstruction syndrome, and
occurs primarily following allogeneic bone marrow transplantation, usually within the first 3
weeks.
The incidence approaches 25% in recipients of allogeneic marrow transplants.
Sinusoidal obstruction syndrome can occur in cancer patients receiving chemotherapy, especially with agents such as gemtuzumad and ozagamicin, used in the treatment of acute myeloid leukemia, actinomycin D in the treatment of Wilms’ tumors, dacarbazine (a drug activated by sinusoidal endothelial cells), and in patients who receive cytotoxic agents such as
cyclophosphamide before bone marrow transplantation(discussed below).
What is the mortality rate of Sinusoidal Obstruction Syndrome (Veno-Occlusive Disease)?
The mortality rates
can be higher than 30%.
What is the gold standard for the diagnosis of Sinusoidal Obstruction Syndrome (Veno-Occlusive Disease)?
Although histology is the gold standard for the diagnosis, a diagnosis of sinusoidal obstruction syndrome is frequently made on clinical grounds only (tender
hepatomegaly, ascites, weight gain, and jaundice), because of the high risk of liver biopsy in
these patients.
What is the morphology of Sinusoidal obstruction syndrome?
Sinusoidal obstruction syndrome is characterized by obliteration of hepatic vein
radicles by varying amounts of subendothelial swelling and finely reticulated collagen.
In acute disease there is striking centrilobular congestion with hepatocellular necrosis and
accumulation of hemosiderin-laden macrophages.
What is the clinical course of Sinusoidal Obstruction Syndrome (Veno-Occlusive Disease)
As the disease progresses, obliteration of
the lumen of the venule is easily identified with special stains for connective tissue ( Fig. 18-
40 ).
In chronic or healed sinusoidal obstruction syndrome, dense perivenular fibrosis
radiating out into the parenchyma may be present, frequently with total obliteration of the
venule; hemosiderin deposition is evident in the scar tissue, and congestion is minimal.
Sinusoidal Obstruction Syndrome (Veno-Occlusive Disease)
FIGURE 18-40 Sinusoidal obstruction syndrome (previously known as veno-occlusive
disease).
Reticulin stain reveals the parenchyma framework of the lobule and the marked
deposition of collagen within the lumen of the central vein.
