This document discusses infarcts, which are areas of ischemic necrosis caused by occlusion of the arterial supply or venous drainage. It defines infarcts and lists common causes like thrombotic occlusion. It describes different types of infarcts based on color, age, and presence of infection. Pathogenesis involves local hyperemia, edema, hemorrhage, and cellular changes leading to necrosis replaced by fibrous tissue. Gross morphology shows wedge-shaped lesions pointing toward the occluded vessel. Microscopy typically shows coagulative necrosis and inflammatory reaction at the periphery replaced by fibrous tissue. Commonly affected organs and outcomes are also outlined.

1. INFARCT
Dr . Sridevi
Post Graduate
Department of Pathology

2. Plan
1. Definition
2. Causes
3. Types
4. Pathogenesis
5. Gross
6. Microscopy

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

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

5. Types
1. Colour
2. Age
3. 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
Depressedunder
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