What does infarct-type necrosis mean?
Infarct-type necrosis, also known as coagulative necrosis, is a type of necrosis that occurs due to a sudden loss of blood supply to a tissue, leading to the death of the affected cells. It results in a distinctive pattern of tissue damage that has certain characteristics. Here's what infarct-type necrosis means:
- Sudden Loss of Blood Supply: Infarct-type necrosis is triggered by a severe reduction or complete cessation of blood flow to a specific area of tissue, causing a lack of oxygen (ischemia) and essential nutrients necessary to support cell survival. This sudden loss of blood supply can be due to various factors like blood vessel blockage, such as in cases of thrombosis (blood clots) or embolism (obstruction by foreign particles or air bubbles).
- Coagulative or Ischemic Necrosis: The term "coagulative" or "ischemic" refers to the appearance and characteristics of the affected tissue in infarct-type necrosis. The sudden deprivation of oxygen and nutrients leads to extensive cellular damage and death, resulting in coagulation of the intracellular proteins and preservation of the tissue architecture to some extent.
- Well-Defined Borders: Infarct-type necrosis often presents with clear and well-demarcated borders that separate the dead tissue (infarct) from the surrounding healthy tissue. This is due to the coagulation of proteins within the dead cells and the inflammatory response around the infarcted area.
- Firm Consistency: The infarcted tissue tends to be firm and may have a rubbery consistency, which can be attributed to the coagulative nature of protein changes within the dead cells.
- Histological Findings: Microscopically, infarct-type necrosis shows various changes in the tissue structure and cellular components. The cells in the affected area undergo nuclear pyknosis (shrinkage of the nucleus) and karyorrhexis ( fragmentation of the nucleus). The cytoplasm becomes eosinophilic (stains deeply with eosin stain) and the tissue might exhibit hyalinization, where the affected areas appear structureless and glassy due to the denaturation of proteins.
- Inflammatory Response: Infarct-type necrosis triggers a subsequent inflammatory reaction as the body attempts to remove the dead tissue and repair the damaged area. This inflammatory process is essential for initiating the healing process and limiting tissue damage.
In summary, infarct-type necrosis is characterized by sudden and severe loss of blood supply, leading to coagulative changes in the affected tissue. It presents with clear borders, firm consistency, and histopathological features that allow for its identification and differentiation from other types of necrosis.