Infarct

INFARCT

1. INFARCT Dr . Sridevi Post Graduate Department of Pathology

2. Plan Definition Causes Types Pathogenesis Gross Microscopy

3. Definition Infarct is an area of ischemic necrosis caused by occlusion of either the arterial supply or the venous drainage

4. Causes Thrombotic or Embolic arterial occlusion Local vasospasm Hemorrhage into the atheromatous plaque Extrinsic vessel compression by tumour Torsion of vessels Traumatic rupture Anterior compartment syndrome

5. Types Colour Age Infection

6. Colour Pale or Anemic Red or Hemorrhagic d/e Arterial occlusion d/e Pulmonary arterial occlusion Compact organs Arterial or Venous occlusion End artery blood supply soft tissue Eg : Kidney, Heart, Spleen Dual blood supply Eg : Lungs , Intestine

7. Age Recent or fresh Old or Healed Slightly elevated over the surface Shrunken or Depressed under the surface

8. Infection Bland Septic Without infection With infection

9. Pathogenesis Local hyperemia Affected part becomes edema & hemorrhage Cellular changes- Reversible cell injury Progressive Proteolysis Acute inflammatory reaction & Hyperemia Blood pigments Growth of granulation tissue Infarct replaced by fibrous tissue

10. Morphology – Gross Wedge shaped Apex pointing towards occluded artery Base on the surface Arterial occlusion- Pale Venous occlusion – Hemorrhagic

11. Microscopy Pathognomic – Coagulative necrosis ( all organs) Cerebral infarcts – Liquefactive necrosis Periphery of the infarct- Inflammatory reaction noted Generally infarct replaced by fibrous tissue Cerebral infarct – Gliosis ( replacement by microglial cells)

12. Infarct lung Gross Microscopy Wedge shaped Lower lobes Cut surface – Dark purple Coagulative necrosis Infiltration of neutrophils Alveolar capillary congestion

13. Infarct kidney Gross Microscopy Multiple Bilateral Pale or Anemic Base- Wedge shaped under capsule Apex- Pointing the medulla Coagulative necrosis Ghost of renal tubules & glomeruli Without intact nuclei & cytoplasm

14. Infarct spleen Gross Microscopy Multiple Pale or Anemic Base – Wedge shaped Apex – Pointing towards hilum Coagulative necrosis Inflammatory cell infiltrate

15. Infarct liver Gross Microscopy Anemic or hemorrhagic Infarcts of Zahn- Non ischemic infarct Infarcts of Zahn

16. Most commonly affected organs Location Gross Outcome Myocardium Pale Frequently lethal Lungs Hemorrhagic Less fatal Cerebrum Hemorrhagic or pale Fatal if massive Intestine Hemorrhagic Frequently lethal Renal Pale No lethal Spleen Pale Not lethal Liver Pale Not lethal Lower extremities Pale Not lethal