Also found in: Dictionary, Thesaurus, Medical, Wikipedia.


An excess of blood within an organ or tissue caused by blood vessel dilation or impaired drainage, especially of the skin.



also plethora, an excess of blood in a tissue or organ. One may distinguish arterial and venous hyperemia. Arterial (active) hyperemia arises as a result of increased blood flow in the arteries owing to increased tonus of the vasodilator nerves or decreased tonus of the vasoconstrictor nerves. Among its causes are increased sensitivity of the blood vessels to physiological stimuli or the influence of extraordinary stimuli (such as bacterial toxins, high temperature, and products of tissue decomposition); in humans psychogenic factors (such as shame and anger) play a large role. Arterial hyperemia is characterized by dilatation of the arteries in the hyperemized area, elevation of temperature in the area, acceleration of blood flow, and reddening (for example, hyperemia of the face). It is accompanied by intensification of metabolic processes in the tissues and promotes the regeneration of tissues. Hemorrhages may occur during arterial hyperemia if there are pathological changes in the blood vessels. Arterial hyperemia is induced for therapeutic purposes by means of mustard plasters and cupping glasses. Venous (passive, static) hyperemia occurs when the outflow of blood along the veins is obstructed as a result of pressure on the venous wall (cicatrix, tumor, varicose dilatation of the veins, or edema), while the inflow remains unchanged or when there is a weakening of cardiac activity. Venous hyperemia is characterized by deceleration of blood flow to the point of complete stasis. Oxygen deficit develops in the tissues, the vascular walls become more permeable, and edema develops. Prolonged blood stasis and edema may lead to atrophy of the parenchyma of an organ.


References in periodicals archive ?
14-17) In this case, the observed clinical signs were severe feather loss from the body with diffuse hyperemia, severe lichenification, and crusting.
Jack Elands, Chief Executive Officer of Amakem, said: "AMA0076 has demonstrated IOP reduction without significant hyperemia, the first ROCK inhibitor to achieve this goal in the clinic.
In the Framingham Heart Study offspring cohort increased aortic stiffness was associated with higher forearm vascular resistance at baseline and during reactive hyperemia, and with blunted flow reserve during hyperemia (39).
The typical clinical picture includes palpebral edema, bulbar hyperemia and conjunctival hyperemia accompanying sudden, painful, abundant purulant discharge in the first 2-5 days of life (7,8).
A transient increase in skin blood flow after ischemia is regulated by a protective mechanism called reactive hyperemia [4850,56-57].
The diameter of brachial artery was measured by 10 MHz transducer in longitudinal section on 2-1,5 cm above the elbow bend before and after tests with reactive hyperemia through 30-90 seconds.
Specifically, the previously seen hyperemia and stromal oedema had resolved.
After 20-day applications of XKJ, colonic samples showed alleviations of the hyperemia, edema, and the quantities of ulcerations.
Wound space was filled with young granulation tissues that had bleeding, hyperemia and intense necrotic changes and was infiltrated by inflammatory cells.
Flow-mediated dilatation of the brachial artery was evaluated after reactive hyperemia induced by cuff obstruction of the forearm, using high-resolution ultasonography.
Most adverse reactions with LACRISERT were mild and transient and included transient blurring of vision, ocular discomfort or irritation, matting or stickiness of eyelashes, photophobia, hypersensitivity, edema of the eyelids, and hyperemia.