All are reversible injury of cell, except
**Cell Injury and Repair**
**Core Concept**
Cell injury can be reversible or irreversible, depending on the severity and duration of the insult. Reversible cell injury is characterized by cellular dysfunction and metabolic derangements, whereas irreversible cell injury leads to cell death and necrosis.
**Why the Correct Answer is Right**
The correct answer is an irreversible cell injury. Irreversible cell injury occurs when the cell's energy production is severely impaired, leading to a catastrophic collapse of cellular homeostasis. This type of injury is often seen in cases of severe ischemia, toxic exposures, or overwhelming infections. The cell membrane becomes permeable, leading to a massive influx of calcium ions, which triggers a cascade of intracellular events that ultimately result in cell death.
**Why Each Wrong Option is Incorrect**
* **Option A:** This is a reversible cell injury, such as that seen in hypoxia or ischemia. The cell's energy production is impaired, but the injury is still reversible if the insult is removed.
* **Option B:** This is also a reversible cell injury, such as that seen in hypokalemia or metabolic derangements. The cell's function is impaired, but the injury is still reversible if the underlying cause is corrected.
* **Option D:** This is a reversible cell injury, such as that seen in viral infections or autoimmune diseases. The cell's function is impaired, but the injury is still reversible if the underlying cause is treated.
**Clinical Pearl / High-Yield Fact**
It's essential to note that reversible cell injury can progress to irreversible cell injury if left untreated. Therefore, prompt recognition and treatment of reversible cell injury are crucial to prevent further cellular damage.
**Correct Answer:** A.