What Is the Brain Parenchyma?

The brain parenchyma is the functional tissue in the brain. It's comprised of two types of cells that are used specifically for cognition and controlling the rest of the body. The remaining brain tissue is known as stroma, which is the supportive or structural tissue. Damage or trauma to the brain parenchyma often results in a loss of cognitive ability or even death.

The brain parenchyma consists of neurons and glial cells. The neurons fulfill three main functions: afferent neurons are used to transmit messages from sensory organs to the brain and Central Nervous System (CNS), while efferent neurons send information and commands from the CNS to the muscles and glands. The third type, interneurons, are used for communication between the other two types.

These are supported and maintained by three types of glial cells. Oligodendroglia surround and insulate them, while astroglia physically support them and provide them with nutrition. They also eat debris and parts of dead neurons, as do microglia, the third type. Additionally, they regulate the concentration of ions in the space in between cells in the brain parenchyma, which keeps the organ as a whole functioning properly, and support the blood-brain barrier, which prevents certain substances from entering the brain via blood vessels. These cells also help with repairs following an injury.

The other categorization of cells in the brain is stroma, which includes blood vessels and connective tissue. It consists primarily of two sets of arteries, three sets of veins, and smaller capillaries that penetrate into the tissue, and the connective tissue that supports them. Though it doesn't perform the cognitive and management functions that the brain parenchyma does, it's still essential for the brain to function, since it provides it with nutrients and oxygen from the rest of the body. Additionally, problems with the stroma can be extremely serious. For example, if a cerebral blood vessel ruptures, the subsequent hemorrhaging can cause blood to build up in parenchymal tissue, raising the risk for stroke or memory loss.

A number of different conditions can affect the brain parenchyma. Changes due to age, deterioration, trauma, or damage to the stroma can cause a wide range of conditions, including dementia, Alzheimer's, Parkinson's disease, epilepsy, multiple sclerosis, and Amyotrophic Lateral Sclerosis (ALS). Infections can also affect these cells, as in the case of encephalitis or meningitis. Additionally, cell abnormalities can lead to growths and tumors that can put pressure on or permanently damage the surrounding tissue or spread throughout the body.

Brain parenchymal treatment depends on the specific medical condition a patient faces. Generally, injuries to the brain parenchyma are known as brain lesions, which involve damaged brain tissue. There are multiple different treatments for brain lesions, including:

Central nervous system relapse including the brain parenchyma occurs in about 5 percent of patients with systemic non-Hodgkin lymphoma. The condition may also impact the spinal cord, eyes, or leptomeninges. Research shows that the best treatment for isolated central nervous relapse is systemic methotrexate.

High-dose systemic methotrexate and intrathecal chemotherapy used in combination have shown the best results. 

White matter disease is also when the deepest and largest part of the brain tissue wears away. A physician may prescribe cholesterol-lowering medication or pills to help decrease your blood pressure. Also, you should not smoke when facing white matter disease.

Parenchymal brain damage relates to the harming of functional brain tissue. Furthermore, parenchymal brain damage is a complication that takes place due to various medical conditions. It can be a serious side effect from:

Furthermore, parenchymal brain injuries can occur among patients with abusive head trauma. Parenchymal brain damage and injury can lead to blindness, epilepsy, gross motor and cognitive impairment, and behavioral issues. 

Another form of parenchymal brain damage is known as a parenchymal hemorrhage or an intraparenchymal hemorrhage, which is a bleed taking place within the functional tissues of the brain. 

This happens when a blood vessel in the brain ruptures and harms the normal blood flow in the brain. As such, the patient doesn’t get an adequate amount of oxygen in brain tissues. Hypertension or high blood pressure can lead to the rupture of a blood vessel in the brain.

Cerebral amyloid angiopathy can also cause this, which is the accumulation of abnormal proteins in the brain’s arteries.

Brain parenchymal volume loss is seen on cross-sectional imaging and is known as cerebral atrophy. Essentially, it entails losing neurons and links between those neurons. You will find various diseases can lead to brain parenchymal volume loss or brain atrophy, such as:

Further, head or brain injuries can lead to brain parenchymal volume loss and atrophy. Patients who smoke, drink heavily, and/or are at an advanced age tend to increase their risk of brain atrophy. In addition, brain atrophy can lead to dementia among older patients.

They will struggle with thinking and remembering to the point of finding everyday life overly difficult. Such patients can get Alzheimer’s disease due to brain atrophy. These neurodegenerative diseases may cause aphasia, which involves speaking and language issues.

Brain atrophy can also lead to seizures, loss of consciousness, and bitter or metallic tastes.

A parenchymal stroke is a type of hemorrhagic stroke. The two other types of hemorrhagic strokes include arteriovenous and subarachnoid malformations. A parenchymal hemorrhage is a brain bleed that takes place within the parenchymal tissues. It can disrupt blood oxygen flow in brain cells and even lead to the destruction of functional brain tissue.

An intraparenchymal hemorrhage is responsible for less than 20 percent of all strokes, but it does have the highest mortality risks of all stroke types. Headaches, seizures, and neurological deficits can occur from a parenchymal stroke. Patients often have speech, vision, and hearing issues. 

The causes of hemorrhagic strokes include smoking, drinking alcohol heavily, and having high blood pressure or hypertension. Doctors can conduct blood coagulation studies and imaging studies to determine if a patient has a parenchymal hemorrhage.

Physicians may prescribe blood-thinning medication or anticoagulants along with mannitol or hypertonic saline. Platelet therapy is another option for treating that type of stroke.