The Difference Between Apoptosis and Necrosis

The process of apoptosis is an organism’s own internal “waste management” process for getting rid of its own damaged, unneeded, and potentially dangerous cells. It is a physiologic (normal operating activity of a living matter) also referred to as “programmed cell death,” or “cell suicide.” Cells are removed from the body because they are damaged, infected, possibly cancerous, or otherwise not normal. It is a way to prevent infection, to delete cells that are not needed any longer, or to arrest the spread of cancer or prevent the disruption of homeostasis.

Apoptosis occurs as an orderly process by which the target cell is condensed or taken apart then removed from the body by the immune system. Cytotoxic T-cells are activated and trigger the process, in which the affected cell shrinks, forms blebs (bulges in plasma membrane). Proteins activated by apoptosis break down the cell. Enzymes break down the nucleus and signal macrophages (large white blood cells that engulf and the cell and use enzymes to destroy it) to remove the cell components from the body. Surrounding cells and tissues are not damaged in the process. No interventions are needed for apoptosis- it is a normal and necessary body function that causes no harm to the body.

Necrosis (which can be seen as “cellular homicide), unlike apoptosis, is a pathologic process. While apoptosis can be seen as “cellular suicide,” necrosis can be described as “cellular mass homicide.” Necrosis is triggered by external factors: damage, infection, or trauma to the cells. Apoptosis occurs in selected cells, but necrosis is the swelling, acidosis, and liquefaction (death) of cells en masse. Necrosis causes inflammation and damage to surrounding normal tissue. Unlike apoptosis - which requires no intervention- necrosis causes irreversible harm and requires immediate and aggressive medical treatment to (1) remove the necrotic tissue and (2) discovery and treatment of the underlying cause.

I have been involved in treating several patients suffering from necrosis. The greatest number of patients treated also had IDDM or NIDDM, which can cause PAD (peripheral arterial disease). PAD causes restricted blood flow to the extremities, particularly the lower extremities. Lack of blood flow leads to diabetic foot ulcers, which then failed to heal (delayed healing is also a complication of DM). The condition progressed into necrosis because the body's vasculature could not provide enough blood flow into and out of the area to support the tissues. It was not uncommon to see patients with uncontrolled diabetes with toes, feet, even legs amputated. Surgical amputation has risks of its own, and risk of complications from surgery increase for patients with comorbidities. Treatment includes removing necrotic tissue and pus, preventing the spread of damage, and managing conditions causing necrosis.

Scrupulous cleaning, removal of necrotic tissue and pus, and hygiene are of the utmost importance. Careful, detailed, and accurate documentation of the extent of damage, patient response to treatment, and using an multi-disciplinary approach to management. Maintaining communication with the dietitian, diabetes educator, nurse, physician, and all other health care professionals involved in the patient's care can help ensure the patient can achieve the best possible outcome by using every available source of care needed.

In the case where a patient must have a surgical removal of a body part - no matter how small - it is often helpful to enlist the services of a mental health professional who can assist the patient with working through the grieving process. I have heard (insensitive) people say 'but it's just a little toe, what is the big deal?' Anything that is a big deal to the patient IS a big deal! Losing a body part, no matter what it is, can be traumatic. Patients can and do grieve over their loss. Providing care for their emotional and mental wellness is as important as caring for their physical wellness.