Please enable JavaScript.

Coggle requires JavaScript to display documents.

Infarction, image …

- - - - Venous Occlusion
        What is Venous Occlusion ?
        Venous Occlusion is the decreased outflow of blood from an organ drained by a single large vein.
        eg: Testis and Ovaries
        Venous Occlusion is due to thrombosis and torsion of pedicle of organ.
        An increase in pressure prevents arterial inflow, resulting in infarction of organ.
        NOTE: An organ with multiple outflow channels, is less likely to experience infarction.
        Why ?
        Increased pressure distends patent veins.
- - - - Septic Infarcts
        What is a Septic Infarct ?
        A septic infarct is caused by the bacterial contamination of an infarct.
        What causes the Bacterial Contamination ?
        The Bacterial Contamination is caused by:
        Prior Bacterial Infection: Pneumonia
        Septic Embolus: Infective Endocarditis
        Bacteraemic seeding at edge of infarct
        Proliferation of normal commensals in necrotic tissue.
- - - - Later Lesions
        What are Later Lesions ?
        After a day, white infarcts will become pale, and Haemorrhagic Infarcts will remain dark.
        White/Pale Infarcts are better defined as colour changes.
        Firm due to inflammation
        Have a rim of Hyperaemia
        Fibrinous exudate on serosa.
        Red/ Haemorrhagic Infarcts
        Better Defined as colour changes: Red to blue
        Ill-defined edge
        Fibrinous exudate on serosa.
- - - - Haemorrhage
        A haemorrhage masks other changes.
        
        Inflammation and Repair
        Inflammation and Repair commences within hours of infarction.
        Cells migrate from adjacent microvasculature and can be used to estimate the duration of the infarct.
        Fibrosis moves inward from margins to leave a scar.
        May see residual necrotic debris in large infarct.
        
        Liquefaction
        Liquefaction is more common in brain infarcts.
        Liquefaction and Phagocytosis of necrotic debris results in a Cyst.
        The Cyst will then be surrounded by glial proliferation to form a reparative scar.
        
        Abscess Formation
        Abscess formation occurs in a Septic Infarction.
        In later stages: may not be able to recognise underlying infarct.
- - - - Rate of Occlusion
        Slow rate of occlusion is better tolerated as it allows time for the development of collaterals.
        
        Vulnerability of Tissue
        Neurones of the brain
        Renal Tubules
        Cardiac Myocytes
        Are more sensitive to Ischaemia
        Fibroblasts are more resist to Ischaemia.

     This a cross section of an artery with occlusive thrombus superimposed on a ruptured atherosclerotic plaque.