Circulatory disorders in the liver

Blood supply features and systemic disorders

The liver is characterized by a unique vascular angioarchitecture. It features a dual blood supply, extremely intensive intraorgan blood flow, and a robust venous outflow system.

It is the disturbance of normal blood circulation that is recognized as the most frequent cause of large-scale hepatic tissue remodeling. An important clinical and morphological feature is that hemodynamic shifts always leave a mark on the organ's structure, but due to high compensatory reserves, the clinical picture may remain completely asymptomatic for a long time.

In addition to local problems, the parenchyma suffers from systemic circulatory damage. Most commonly, these manifest in the development of acute or chronic cardiovascular failure, when adequate organ perfusion is globally disrupted.

Mechanical sinusoidal occlusion

Blockage of the hepatic microvasculature triggers a rapid cascade of pathological reactions.

Main causes of mechanical occlusion:

• Sickle cell anemia.
• Disseminated intravascular coagulation syndrome (DIC syndrome).
• Malignant hematological diseases (lymphomas and leukemias).

Pathogenesis of the lesion: The lumen of the sinusoids is blocked by microthrombi or clusters of tumor cells. This causes a sharp disruption of blood flow and local ischemia. Under conditions of hypoxia, hepatocyte necrosis rapidly ensues, ultimately leading to a severe complication—fulminant hepatic failure.

Venous outflow pathology

Disruption of venous blood outflow is accompanied by pronounced macroscopic and microscopic changes, and without timely treatment, it is characterized by extremely high mortality.

Macroscopic picture: Examination of the vascular bed reveals thrombotic masses within the lumen of the hepatic veins or the inferior vena cava. By nature, they can be:

1. Fresh obliterating (completely blocking the lumen).
2. Mural.
3. Organizing (with connective tissue ingrowth).

Histological changes:

• Extreme venous congestion is recorded in the central regions of the hepatic lobules.
• Centrilobular hepatocyte necrosis develops.
• If vascular occlusion occurs gradually, fibrosis forms in place of the dead cells in the central regions of the lobules.

Veno-occlusive disease

This is a specific disorder of the terminal hepatic veins, having clear diagnostic criteria and characteristic morphology.

Etiology and epidemiology: Historically, the disease was first described in Jamaica, where locals consumed tea containing toxic pyrrolizidine alkaloids. In modern clinical practice, the main cause is a specific bodily reaction in bone marrow transplant recipients. In this patient cohort, the pathology causes death in 30% of cases.

Clinical presentation: The diagnosis is based on characteristic symptoms:

• Liver tenderness upon palpation.
• Development of ascites.
• Rapid weight gain (due to fluid retention).
• Jaundice.

Pathomorphology: The essence of the process lies in the obliteration of the terminal hepatic vein basin. The damage mechanism is associated with marked edema and the deposition of fine-fibrillar collagen in the subendothelial space of the vessels. The cellular infiltrate shows macrophages densely loaded with hemosiderin pigment.

In the chronic course of the disease, perivenular fibrosis actively spreads deep into the lobular parenchyma. This frequently results in complete obliteration of the central veins and is accompanied by focal hemosiderosis of the organ tissue.

Class and exam questions

What else to study on this topic

• Morphogenesis of fibrosis in chronic cardiovascular failure
• The role of DIC syndrome in hepatic microcirculatory disorders
• Differential diagnosis of thrombosis of the inferior vena cava and hepatic veins
• Histological stages of veno-occlusive disease in bone marrow recipients
• Mechanisms of hemosiderin accumulation in venous congestion

Other topics in the section "Diseases of the Liver, Biliary System, and Exocrine Pancreas"

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.