If the liver has a single lesion and is the only tissue affected, how did the bacteria likely reach the liver?

If the liver has a single lesion and is the only tissue affected, how did the bacteria likely reach the liver?

• A. Umbilical vein
• B. Portal circulation
• C. Systemic hematogenous spread
• D. Biliary tree

Answer: (B)

Bacteria reaching the liver most plausibly come from the gut through the portal circulation. Blood from the gastrointestinal tract drains via the portal vein directly into the liver, making the liver the first organ to filter gut-derived bacteria. A single hepatic lesion suggests this gut-to-liver route, because bacteria that travel this way are delivered to the liver as a focal seed rather than spreading widely. In contrast, systemic hematogenous spread would more often produce multiple foci and involve other tissues; spread through the biliary tree would typically follow biliary infection patterns and lesions along the biliary ducts or evidence of biliary disease. The umbilical vein is a fetal conduit and not a typical route for postnatal infection.

Bacteria reaching the liver most plausibly come from the gut through the portal circulation. Blood from the gastrointestinal tract drains via the portal vein directly into the liver, making the liver the first organ to filter gut-derived bacteria. A single hepatic lesion suggests this gut-to-liver route, because bacteria that travel this way are delivered to the liver as a focal seed rather than spreading widely.

In contrast, systemic hematogenous spread would more often produce multiple foci and involve other tissues; spread through the biliary tree would typically follow biliary infection patterns and lesions along the biliary ducts or evidence of biliary disease. The umbilical vein is a fetal conduit and not a typical route for postnatal infection.