Venlo-occlusive disease in hepatic vein is characterized by
**Core Concept**
Venlo-occlusive disease, also known as hepatic veno-occlusive disease (VOD), is a condition that affects the small hepatic veins and terminal hepatic venules. It is characterized by the obstruction of these small veins, leading to congestion and damage to the surrounding liver tissue.
**Why the Correct Answer is Right**
VOD is typically caused by the release of toxic substances, such as pyrrolizidine alkaloids, which are found in certain plants and can be ingested through contaminated food or water. These toxins induce endothelial damage and proliferation, leading to the obstruction of the small hepatic veins. The affected liver tissue becomes congested, leading to hepatomegaly, ascites, and potentially, multi-organ failure.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because VOD is not typically associated with an autoimmune response.
**Option B:** This option is incorrect because VOD is not primarily caused by a viral infection, although some viral infections may exacerbate the condition.
**Option C:** This option is incorrect because VOD is not characterized by the infiltration of malignant cells.
**Clinical Pearl / High-Yield Fact**
VOD is a critical condition that requires prompt recognition and treatment. One key clinical correlation to remember is that VOD often presents with a triad of symptoms: hepatomegaly, ascites, and bilirubin elevation.
**Correct Answer: C. Obstruction of small hepatic veins and terminal hepatic venules.**