Pathophysiology of Hepatic Congestion

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Questions and Answers

What is a potential consequence of ischemic necrosis in centrilobular hepatocytes?

Improved oxygenation

Cell death (correct)

Formation of fatty tumors

Hemosiderin accumulation

Which factor is primarily responsible for immediate arteriolar vasoconstriction at the site of vascular injury?

Clotting factor release

Platelet activation

Reflex neurogenic mechanisms (correct)

Local secretion of histamines

What describes the appearance of centrilobular regions in chronic passive hepatic congestion?

Bright yellow and swollen

Red-brown and slightly depressed (correct)

Pale and necrotic

Bright red and inflamed

What is the main function of hemostasis?

Prevent or limit bleeding Signup and view all the answers

What is the role of hemosiderin-laden macrophages found in the alveoli?

Resulting from phagocytosed red cells Signup and view all the answers

What leads to the formation of a platelet plug during primary hemostasis?

Activation of platelets Signup and view all the answers

In the event of acute hepatic congestion, what happens to the central vein and sinusoids?

They become distended Signup and view all the answers

What vascular change occurs immediately following an injury?

Arteriolar vasoconstriction Signup and view all the answers

What is the role of activated factor Xa in the coagulation cascade?

It converts prothrombin (factor II) to thrombin (factor IIa). Signup and view all the answers

Which component acts as a cofactor for activated factor Xa in the conversion of prothrombin?

Factor Va Signup and view all the answers

What role do calcium ions play in the reaction complexes of the coagulation cascade?

They stabilize the interaction between various components. Signup and view all the answers

Which factors are held together by calcium in the initial reaction complex mentioned?

Factors IX, X, and VIII Signup and view all the answers

What is the formal name of prothrombin in the coagulation cascade?

Factor II Signup and view all the answers

Which amino acid residue is primarily involved in calcium binding within clotting factors?

Glutamic acid Signup and view all the answers

Which combination of components constitutes the initial reaction complex on a phospholipid surface?

Factor IXa, Factor VIIIa, and Factor X Signup and view all the answers

What is the effect of activated factor IX on factor X in the coagulation process?

It converts factor X to factor Xa. Signup and view all the answers

What is a major contributor to the development of venous thrombi?

Stasis Signup and view all the answers

Which of the following can promote endothelial activation?

Prolonged bed rest Signup and view all the answers

Which condition is linked to a deficiency in cystathione β-synthetase?

Homozygous homocystinuria Signup and view all the answers

What effect does turbulence have on blood flow?

Increases leukocyte adhesion Signup and view all the answers

Which of the following is considered a strong risk factor for thrombosis?

Myocardial infarction Signup and view all the answers

Which of these does NOT prevent the washout of activated clotting factors?

Fresh flowing blood Signup and view all the answers

What is a common genetic alteration associated with thrombosis?

Factor V gene mutation Signup and view all the answers

Which condition is classified under secondary (acquired) risk factors for thrombosis?

Heparin-induced thrombocytopenia Signup and view all the answers

What is the inheritance pattern of factor V Leiden?

Autosomal dominant Signup and view all the answers

Which mutation is associated with approximately 60% of individuals with recurrent DVT?

Factor V Leiden mutation Signup and view all the answers

What is the primary consequence of the factor V Leiden mutation?

Resistance to cleavage and inactivation by protein C Signup and view all the answers

How does obesity promote hypercoagulability?

By unknown mechanisms Signup and view all the answers

What condition is characterized by the formation of antibodies against heparin and PF4 complexes?

Heparin-induced thrombocytopenia Signup and view all the answers

What percentage of the population is affected by the prothrombin gene mutation G20210A?

1% to 2% Signup and view all the answers

What is the relative risk increase for venous thrombosis in heterozygotes for factor V Leiden?

Fivefold Signup and view all the answers

Which is a rare inherited cause of primary hypercoagulability?

Deficiencies of anticoagulants Signup and view all the answers

What triggers platelet activation?

Thrombin and ADP Signup and view all the answers

What role do negatively charged phospholipids play in platelet activation?

They serve as nucleation sites for factor complexes. Signup and view all the answers

Which process occurs alongside shape change during platelet activation?

Granule secretion Signup and view all the answers

What is the role of thrombin in the stabilization of the platelet plug?

It activates fibrinogen into fibrin. Signup and view all the answers

Which deficiency is associated with the failure of platelet aggregation?

Thrombasthenia Signup and view all the answers

How do platelets primarily adhere to the extracellular matrix (ECM) following endothelial injury?

Via GpIb receptors binding to VWF. Signup and view all the answers

What occurs during irreversible platelet contraction?

Cementing of fibrin Signup and view all the answers

What additional cells are typically found in hemostatic plugs?

Neutrophils and lymphocytes Signup and view all the answers

Study Notes

Hepatic Congestion and Ischemic Necrosis

Thickened and fibrotic lungs with alveolar macrophages containing hemosiderin indicate chronic conditions, often seen in heart failure.
Central veins and sinusoids in the liver become distended during acute hepatic congestion.
Centrilobular hepatocytes are distal to the hepatic blood supply and may undergo ischemic necrosis, while periportal hepatocytes are better oxygenated and may only show fatty changes.
Chronic passive hepatic congestion leads to centrilobular regions being grossly red and depressed due to cell death, a condition known as "nutmeg liver."
Microscopically, centrilobular congestion and hemorrhage, along with hemosiderin-laden macrophages and hepatocyte necrosis, are observed.

Hemostasis Process

Hemostasis is a complex process involving platelets, clotting factors, and endothelium to form blood clots and prevent bleeding.
Initial response includes arteriolar vasoconstriction to reduce blood flow at injury sites, which is mediated by neurogenic mechanisms and local factors like endothelin.
Primary hemostasis involves formation of a platelet plug, primarily through the binding of GpIb receptors to von Willebrand factor (VWF) on the extracellular matrix.

Platelet Activation and Coagulation

Platelet activation is triggered by factors such as thrombin and ADP, resulting in granule secretion and shape changes, leading to aggregation.
Thrombin plays a crucial role in stabilizing the platelet plug by converting fibrinogen into insoluble fibrin.
Hemostatic plugs may entrap red cells and leukocytes due to their adherence to activated platelets.

Deficiencies and Syndromes

Bernard-Soulier syndrome involves a deficiency in GpIb receptors affecting platelet adhesion.
Glanzmann thrombasthenia is caused by a deficiency in GpIIb-IIIa, impairing platelet aggregation.

Risk Factors for Thrombosis

Common risk factors include prolonged bed rest, myocardial infarction, atrial fibrillation, tissue injury, cancer, and pregnancy.
Acquired conditions like antiphospholipid antibody syndrome and heparin-induced thrombocytopenia increase thrombosis risk.
Hypercoagulability associated with aging is often linked to reduced production of endothelial prostacyclin (PGI2).
Genetic risk factors such as factor V Leiden mutation and prothrombin gene mutation significantly increase the likelihood of venous thrombosis.

Heparin-Induced Thrombocytopenia (HIT)

HIT is a serious condition occurring after unfractionated heparin administration, characterized by antibodies forming against heparin-PF4 complexes.
PF4, found in platelet granules, binds to heparin and alters its conformation, leading to neoantigen formation and antibody production.

Hemostasis Mechanisms

The coagulation cascade requires calcium ions, which bind to γ-carboxylated residues on clotting factors for effective function.
Activated enzyme complexes are essential for converting prothrombin to thrombin, forming the basis of secondary hemostasis.

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Description

This quiz explores the pathophysiological changes occurring in hepatic congestion, detailing the role of macrophages and the structure of the hepatic blood flow. Understand the consequences of heart failure on the liver and analyze the significance of hemoglobin breakdown in the condition. Ideal for students in medical and health science fields.