Liquefactive Necrosis - An Insight

Introduction.

Liquefactive necrosis is a kind of necrosis that leads to the conversion of dead tissues to liquid. This affects the central nervous system, most commonly the brain. In necrosis, body cells die and are digested by lysosomes. Lysozymes are the enzymes present throughout the body. As a result, a liquid-filled or pus-like fluid is formed.

What Is Liquefactive Necrosis?

Imagine a 66-year-old man with symptoms like confusion, drowsiness, and delayed thinking while visiting the doctor. The doctor diagnosed these symptoms as liquefactive necrosis in the brain.

Liquefactive necrosis is a condition affects the central nervous system, most commonly the brain. In necrosis, the body cells die and are digested by lysosomes. Liquefactive necrosis is related to abscess formation in the brain. Abscesses are swollen areas filled with pus or fluids. Liquefactive necrosis causes pus-filled cyst formation in the brain.

What Are the Sites of Occurrence of Liquefactive Necrosis?

Liquefactive necrosis occurs most commonly in the brain due to a higher number of lysosomes. More the lysosomes in the brain, the more the chances of these lysosomes digesting dead cells in the brain and causing liquefactive necrosis.

• Brain: The brain shows excitotoxicity and hypoxic death of cells in the central nervous system. This can cause liquefactive necrosis. In this process, lysosomes convert tissue cells into pus cells due to lysosomal digestive enzymes. This causes a loss of tissue architecture, and tissue liquefaction occurs. Necrotic cells and content disappear.

• Cyst: The affected area is soft and has a liquefied center with necrotic debris. The cyst contains necrotic cell debris and macrophages containing phagocytosed material. The cyst wall consists of proliferating capillaries, inflammatory cells, and proliferating glial fibroblasts. Neural cells have digestive enzymes called hydrolases. These enzymes bring softening of neural tissue.

• Lung: Lung tissue undergoes liquefactive necrosis. Lung abscess occurs in infections when neutrophils are fighting against bacterial infection. This also releases hydrolytic enzymes, which destroy the surrounding tissues.

What Is the Appearance of Liquefactive Necrosis?

Liquefactive necrosis is well-circumscribed, microscopically or macroscopically. The lesion is visible and has dull, opaque, grayish-white to yellowish-gray, soft, partly, or completely fluid-filled. This tissue becomes necrotic and is digested by enzymes like proteolytic enzymes released from the breakdown of leukocytes. This is the characteristic of abscesses and infarcts of the brain. Necrotic brain tissue is soft and semisolid. Liquefactive necrosis is also seen in other organs due to bacterial infections. In infections, there is the release of enzymes from neutrophils. These enzymes destroy the tissue. Liquefactive necrosis is a type of necrosis that transforms the tissue into a liquid content. Due to localized bacterial or fungal infections, the cell is digested entirely by hydrolytic enzymes, forming a soft, circumscribed lesion filled with pus and fluid. Dead leukocytes continue to present as creamy yellow pus. A fluid-filled space remains after the removal of debris by white blood cells. This is the process of abscess formation in the central nervous system.

Liquefactive necrosis occurs when enzymatic digestion occurs predominantly. It is due to the destructive effects of lytic enzymes formed by neutrophils and macrophages in infectious tissues. The result of proteolytic digestion is the liquefaction of necrotic tissue. A bacterial abscess has fluid pus and is an example of liquefactive necrosis. Bacterial infection is the primary cause of liquefactive necrosis. Another cause is an ischemic injury in the central nervous system post occlusion of the arteries. The dead brain tissue turns soft and liquid like a viscous mass. Followed by the development of a cystic space containing clear fluid; the walls of this space have non-necrotic tissue.

What Are the Symptoms of Liquefactive Necrosis?

Liquefactive necrosis symptoms consist of the following:

• Mental changes like confusion, decreased responsiveness, drowsy feeling, coma, lack of attention, irritability, and slow thinking.

• Decreased mobility.

• Decreased sensitivity.

• Loss of speech (aphasia).

• Fever and chills.

• Headache.

• Language difficulties.

• Loss of coordination.

• Loss of muscle function.

• Seizures.

• Stiffness of neck.

• Vision changes.

What Are the Signs of Liquefactive Necrosis?

The affected area is soft, containing liquefied center and necrotic content, followed by cyst wall formation. Microscopically, the cystic space shows necrotic cell debris and macrophages with phagocytosed debris. The cyst wall consists of proliferating capillaries, inflammatory cells, proliferating glial cells in the brain, and proliferating fibroblasts in the abscess formation.

How to Diagnose Liquefactive Necrosis?

A brain and neurological examination usually show increased intracranial pressure and difficulty in brain function. The following tests help in diagnosing liquefactive necrosis:

• Head computed tomography scan.

• Electroencephalogram (EEG).

• Head magnetic resonance imaging.

• Blood tests to detect the presence of microorganisms.

• Complete blood count (CBC).

• Antibodies detection test against Toxoplasma gondii and Taenia solium.

• A fine needle aspiration test is used to find the cause of the infection.

How to Treat Liquefactive Necrosis?

Treatment of liquefactive necrosis is carried out in two ways. Knowing the underlying cause of the necrosis followed by the treatment. Treatment should begin before the dead tissue is dealt with. Even if the primary cause of the necrosis has been ruled out, the necrotic tissue remains in the body. The body has a certain immune response against apoptosis, which is the self-destruction and recycling of the cell. But apoptosis is not triggered due to necrosis and death of the cell.

• Antibiotics can be prescribed. Antibiotics act against different bacteria and such antibiotics are broad-spectrum antibiotics. These antibiotics are commonly used. Different types of antibiotics can be prescribed to evaluate the effect of treatment.

• Antifungal medications are also prescribed if a fungus causes the infection. The standard treatment for liquefactive necrosis is the surgical removal of necrotic tissue. According to necrosis, the treatment varies from removing small skin patches to entirely amputating affected limbs or body parts.

• Chemical treatment with the use of debriding enzymatic agents.

• Maggot therapy can be done.

Conclusion

Liquefactive necrosis, or colliquative necrosis, is due to bacterial or fungal infections. In liquefactive necrosis, the affected cell is digested by hydrolytic enzymes, forming a soft, circumscribed lesion containing pus and the fluid from necrotic tissue. The removal of cell debris by white blood cells causes a fluid-filled space. It leads to abscess formation and is a characteristic of the central nervous system.