â– LECTURE OVERVIEW: Cell injury progresses through a reversible stage before crossing a critical biochemical boundary into irreversible cell injury and cell death.
â– THE CROSSING SEGMENTS:
1. Calcium Accumulation: Depletion of intracellular ATP disables membrane-bound ATP-dependent calcium pumps (Ca2+-ATPase). Calcium rushes into the cytosol and the mitochondria.
2. Enzymatic Overdrive: Elevated cytosolic calcium activates multiple destructive cytosolic enzymes: phospholipases (peroxidizing membranes), proteases (degrading structural cytoskeleton), endonucleases (fragmenting chromatin), and ATPases (further depleting remaining ATP).
3. Heavy Mitochondrial Vacuolization: Mitochondria undergo profound swelling, accumulation of amorphous, calcium-rich dense bodies in the matrix, and permanent loss of membrane potential.
4. Lysosomal Rupture: Low intracellular pH destabilizes lysosomes, releasing acid hydrolases into the cytosol, which digest organelles from within.
5. Nuclear Destruction: Follows a specific sequence: Pyknosis (nuclear condensation), Karyorrhexis (nuclear fragmentation), and Karyolysis (enzymatic disintegration of DNA).
â– PROGNOSTIC CRITERIA & TIMELINE:
Patient outcome scales correlate heavily with diagnostic staging at presentation, age, pre-existing comorbidities, and biological markers of cellular dividing rates.
â– SECONDARY PREVENTION METRICS:
Implementing long-term dietary adaptations, physical therapy, and compliance aids reduces the rate of recurring acute crises by more than half.
[HY-BOARD-1229]
🌟 Dynamic Clinical Key:
The loss of cell membrane permeability is the single most reliable indicator of irreversible injury. This allow tissue-specific intracellular enzymes to leak into systemic circulation where they serve as diagnostic biomarkers: e.g., Cardiac Troponin-I in myocardial infarction, or amylase/lipase in acute pancreatitis. Regularly reassess clinical parameters to adjust long-term therapy. Patient education regarding warning signs and therapy adherence is the cornerstone of secondary prevention.