Which form of hyperemia initiates inflammation?

The initiation of inflammation is associated with pathological active hyperemia. This form of hyperemia occurs as a response to injury or infection where there is an increased blood flow to a specific area, driven by enhanced vasodilation and an increase in vascular permeability. This process is critical because it allows for an influx of immune cells, nutrients, and other substances necessary for the body's inflammatory response.

Pathological active hyperemia can be triggered by various stimuli, such as infections, tissue damage, or other noxious agents. The increase in blood flow helps to deliver leukocytes (white blood cells), which are essential for combating pathogens and initiating the healing process. Additionally, the enhanced blood flow results in the characteristic signs of inflammation—heat, redness, swelling, and pain.

In contrast, generalized passive hyperemia relates more to elevated blood volume without the active tissue response seen in inflammation, while localized passive hyperemia refers to blood pooling in areas due to impaired venous drainage, which does not actively contribute to inflammation. Active hyperemia, while it does involve increased blood flow, does not necessarily indicate a pathological condition—it may also occur in response to normal physiological demands, such as muscle activity. Hence, the distinction lies in the pathological activation of the inflammatory process linked to