Published: 18 Jun 2025

ICD9: 733.40      ICD10: R02.0      ICD11: MC85

Necrosis is the death of cells or tissues within a living organism.
It's a type of cell death that's often caused by external factors such as infection, toxins, trauma, or ischemia (lack of blood supply).

Here's a breakdown of what's important to understand about necrosis:

It's Premature Death: Necrosis is different from apoptosis (programmed cell death), which is a natural and controlled process for removing unwanted or damaged cells. Necrosis is more like an accidental death, often occurring in response to harmful conditions.

Causes: Many things can trigger necrosis, including:
Ischemia: Lack of oxygen due to blocked blood flow (e.g., in a heart attack or stroke)
Infection: Bacterial, viral, or fungal infections can directly damage cells or release toxins that cause necrosis.
Toxins: Exposure to chemicals, poisons, or drugs can be toxic to cells and lead to necrosis.
Trauma: Physical injury, burns, or frostbite can directly damage tissues.
Radiation: Exposure to high doses of radiation can kill cells.
Immunological Injury: In some autoimmune diseases, the immune system mistakenly attacks and destroys healthy cells, leading to necrosis.

Cellular Changes: When a cell undergoes necrosis, it experiences several changes:
Cell Swelling: The cell enlarges due to an influx of water and ions.
Membrane Rupture: The cell membrane breaks down, releasing its contents into the surrounding tissue.
Inflammation: The release of cellular contents triggers an inflammatory response, attracting immune cells to the area.
DNA Degradation: The cell's DNA breaks down.

Types of Necrosis: There are different types of necrosis, characterized by their appearance and the underlying cause:
Coagulative Necrosis: This is the most common type and is often seen in ischemia. The tissue becomes firm and opaque.
Liquefactive Necrosis: The tissue becomes liquid due to enzymatic digestion. This is common in brain infarcts and bacterial infections.
Caseous Necrosis: This type is characteristic of tuberculosis. The tissue has a cheese-like appearance.
Fat Necrosis: This occurs when fat tissue is damaged, often due to trauma or pancreatitis.
Fibrinoid Necrosis: This is seen in blood vessel walls and is characterized by the deposition of fibrin-like material.
Gangrenous Necrosis: A clinical term, usually used to describe necrosis with superimposed bacterial infection, often in a limb. Dry gangrene is like coagulative necrosis, while wet gangrene is like liquefactive necrosis.

Consequences: Necrosis can have serious consequences for the body, including:
Inflammation: The inflammatory response can damage surrounding healthy tissues.
Scarring: Dead tissue may be replaced by scar tissue, which can impair organ function.
Infection: Necrotic tissue can become a breeding ground for bacteria, leading to infection.
Systemic Effects: In severe cases, necrosis can trigger a systemic inflammatory response (sepsis) and even death.

Diagnosis: Necrosis can be diagnosed through various methods, including:
Physical Examination: Observing the affected area for signs of tissue damage.
Imaging Studies: X-rays, CT scans, MRI scans, and ultrasound can help visualize necrotic tissue.
Biopsy: A tissue sample can be examined under a microscope to confirm the presence of necrosis and determine its type.
Blood Tests: Certain blood markers can indicate tissue damage.

Treatment: Treatment for necrosis depends on the underlying cause and the extent of the damage. Options may include:
Treating the Underlying Cause: Addressing the infection, restoring blood flow, or removing toxins.
Debridement: Removing dead tissue to prevent infection and promote healing.
Antibiotics: Treating bacterial infections.
Surgery: In severe cases, amputation may be necessary to remove necrotic tissue.
Hyperbaric Oxygen Therapy: Increasing oxygen levels in the blood to promote healing.

In summary, necrosis is a pathological process involving the death of cells and tissues within a living organism due to external factors. It can have serious consequences and requires prompt diagnosis and treatment.