Hyperaemia

A hyperemia is an excessive supply of blood in an organ or tissue, usually caused by vascular dilation. A hyperemia is the opposite of ischemia.

A hyperemia is caused by an irritation. This can occur as endogenous inflammatory process in the context of an infection or abnormality of the blood circulation. An exogenous occurrence is possible by exogenous irritants. In the skin occurs, for example hyperemia after a circulation-enhancing ointment was applied. This applies among other things to the arterialization of the blood in the capillary blood gas analysis.

A reactive hyperaemia occurs during the measurement of the maximum blood flow, by congestion of the blood flow with a blood pressure cuff, and subsequent reduction of the cuff pressure. After a cold stimulus may lead to reactive hyperemia. In the context of Raynaud's disease, can often be a painful hyperemia.

In pathology is differentiated between the concepts of active and passive hyperemia. An active hyperemia, for example, in the context of inflammation by release of vasoactive substances ( histamine and Others ) occur or neurogenic origin ( emotions, sport). A passive hyperemia is due to a restriction of blood outflow from a tissue (venous congestion ), eg in the context of heart failure ( systemic), cirrhosis of the liver (portal) or thrombosis (local). Persistent passive hyperemia leads to the formation of edema.

• Hematology
• Pathology