Hemodynamics- hyperemia-1.pptx IUIU kampala

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1. HYPEREMIA AND CONGESTION Dr. Ali Waiswa -pathologist

2. Hyperemia and congestion Both terms indicate a local increased volume of blood in a particular tissue Hyperemia Is an active process T he affected tissue is red, resulting from sympathetic stimulation which causes arteriolar dilatation & local redness P roduced due to the engorgement of oxygenated Blood e.g. pathological as in acute inflammation physiological as in exercise

3. Hyperemia is an active process resulting from augmented blood flow due to arteriolar dilation( e.g at sites of inflammation or skeletal muscle during exercise). The affected tissue redder than normal because of engorgement with oxygenated blood

4. Hyperemic lungs

5. Congestion Is a passive process, which could be localized or generalized Congestion is a passive dilatation of veins as a result of partial obstruction to the venous return This will cause bluish coloration due to accumulation of deoxygenated blood .

6. It may occur systemically as in cardiac failure, or it may be local resulting from isolated venous obstruction, the tissue has blue-red color (cyanosis), especially as worsening congestion leads to accumulation of deoxygenated hemoglobin in the affected tissue The stasis of poorly oxygenated blood causes chronic hypoxia , which in turn can result in degeneration or death of parenchymal cells and subsequent tissue fibrosis . Capillary rupture at such sites of chronic congestion can also cause small foci of haemorrhage , phagocytosis and catabolism of the erythrocyte debris can result in accumulations of hemosiderin-laden macrophages.

7. Venous congestion can be either general or local. General venous congestion: Where the whole venous return is impaired by chronic obstructions e.g. Pulmonary congestion: in cases of left sided heart failure as in mitral stenosis → raised pressure in the pulmonary veins → alveolar capillaries become tortuous & distended with red cells. Congestion and edema commonly occur together. In long-standing congestion, there is chronic hypoxia. Morphology , grossly, the cut surface is hemorrhagic and wet. Microscopically, there is engorgement of capillaries by blood.

8. Lung pulmonary congestion

9. Congestion of the liver usually follows right sided heart failure → liver moderately enlarged & tender. Micro :-- blood accumulate in the central veins &sinusoids with central hepatocytes degeneration . the peripheral hepatocytes are better oxygenated because of their proximity to hepatic arterioles so they are less hypoxic &may only develop fatty changes giving liver an appearance called "nut meg liver". Congestion of the spleen: produce enlargement of the spleen "splenomegaly " with focal hemorrhage & eventually fibrous scars. .

10. Nutmeg liver appearance

11. Local venous congestion : follows mechanical interference with the venous drainage from an organ --- e.g. limbs in DVT caused by Venous thrombosis . --- compression of a vein by tumor or bandage. Local venous congestion will result in localized oedema &ischemic necrosis

12. Hemorrhage: It indicates extravasations of blood due to vessel rupture. Hemorrhage may be; Acute; Causes include mostly trauma Chronic (compensatory mechanisms) eg in menorrhagia, Peptic ulcer disease, colorectal maliganacies Patterns include; 1. External bleeding. 2. Internal bleeding (hematoma, hemothorax , hemoperitoneum , hemopericardium , hemarthrosis ). 3. Petechiae (1- to 2-mm). 4. Purpura (>3mm). 5. Ecchymoses (>1 to 2cm).

13. The clinical significance of hemorrhage depends on; Volume and rate of bleeding . The site involved . Duration (acute versus chronic or recurrent).

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