How much do you know about white matter lesions? This article will help you get out of your blind spot

Author: Xu Yanjie, deputy chief physician of Beijing Longfu Hospital

Reviewer: Yang Zhiqiang, Chief Physician, Beijing Longfu Hospital

Patients often hold their head MRI reports and ask me: "What is white matter lesions? Is this disease serious? At what stage do we need to start treatment? How can we prevent white matter lesions?" Let us now learn about the relevant knowledge about white matter lesions.

1. What is white matter?

Before we talk about white matter lesions, we first need to understand what white matter is. White matter is where the nerve fibers in our brain run. Because the color of this area is lighter than where nerve cells gather, it is a bit whitish, so it is called white matter; the corresponding cerebral cortex or deep nerve nuclei are slightly darker in color and are called gray matter.

The white matter of the brain is composed of many bundles of nerve fibers that transmit nerve impulses within the spinal cord and between the spinal cord and various parts of the brain. If nerve fibers are compared to wires, then the layer of skin wrapped around the wires is called the myelin sheath of the nerve fibers. When nerve fibers degenerate or become damaged due to various reasons, white matter lesions will occur. The main feature is demyelination of the white matter in the corresponding area, which presents a white high signal on a specific sequence of magnetic resonance imaging. After demyelination occurs, this nerve fiber cannot perform the transmission function it is supposed to undertake. Current studies believe that the etiology of periventricular white matter hyperintensities and deep white matter hyperintensities is different. Deep white matter hyperintensities are usually considered to be caused by chronic small vessel ischemia; periventricular white matter hyperintensities are usually considered to be caused by a variety of reasons such as demyelination, granular ependymitis, subependymal gliosis, and small vessel ischemia.

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2. What are the dangers of white matter lesions?

Most white matter lesions have an insidious onset and may not show clinical symptoms in the early stages of the disease. They may not be discovered in time. Some patients discover them only after experiencing memory loss or other symptoms. Depending on the location, number, and size of the lesions, different symptoms may occur, including memory loss, slow response, slow and uncoordinated movements, falls, emotional apathy, personality changes, insomnia or decreased sleep quality, and urinary and bowel control disorders.

Of course, when white matter lesions are severe or occur in special areas, they may also cause symptoms of focal neurological dysfunction such as hemiplegia and aphasia.

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3. What causes white matter lesions?

The causes of white matter lesions can be divided into primary and secondary.

1. Primary refers to white matter lesions, which are a type of disease with a clear genetic tendency and are common in children and adolescents. They are caused by gene mutations, chromosomal abnormalities, and metabolic enzyme abnormalities that cause disorders in the myelination of the central nervous system. Patients are affected by the congenital incomplete development of the myelin sheath, which will cause insufficient secretion of oligodendrocytes in the central nervous system, which in turn causes malnutrition of the white matter and leads to its functional abnormalities. Genetic testing can improve the accuracy of diagnosis. Most patients can only avoid abnormal brain development or white matter degeneration caused by metabolic disorders by reducing the content of metabolic enzymes, reducing the intake of lipids or certain elements, and can also improve the symptoms of white matter degeneration by supplementing substances such as protein hydrolysates and nerve growth factors. The prognosis of primary white matter lesions is poor, and most patients have a short life span.

2. The main causes of secondary white matter lesions include immune system diseases, infectious factors, toxic lesions, malnutrition, tumors, etc.

(1) When the patient's immune system is damaged, immune cells such as lymphocytes and monocytes will attack the spherical cells gathered near the white matter. Over time, this will lead to white matter lesions in the brain. Specific diseases include multiple sclerosis, systemic lupus erythematosus, rheumatoid arthritis, etc.

(2) Viruses such as human immunodeficiency virus (HIV) and neurosyphilis can damage or kill cells that produce myelin in the central nervous system, thereby inhibiting the formation of myelin. If the brain cannot obtain adequate nutrition for a long time, it will induce white matter lesions.

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(3) Common toxic diseases include alcohol poisoning, carbon monoxide poisoning, heavy metal poisoning, etc. For patients with toxic diseases, if they do not receive timely rescue measures, the risk of degenerative lesions in the white matter of the brain will be significantly increased.

(4) Hypertension, smoking, diabetes, obstructive sleep apnea, chronic obstructive pulmonary disease, chronic renal insufficiency, dyslipidemia, hyperhomocysteinemia, tumors, trauma, etc. can all lead to white matter lesions.

【Case Study】

Earlier this year, a young girl developed neuropsychiatric symptoms again 20 days after carbon monoxide poisoning, showing slow reaction and tremors in her limbs, i.e. delayed encephalopathy. Although she sought medical treatment promptly, she still had obvious neurological deficits such as limb weakness, movement disorders, amnesia, and decreased calculation ability after treatment, which was considered to be degenerative lesions of the white matter caused by carbon monoxide poisoning.

4. At what stage does white matter lesions require active treatment?

In clinical practice, white matter lesions are mainly graded through cranial magnetic resonance imaging examinations and are divided into three levels according to the Fazekas grading method.

Level 1 mild lesion: Only dot-like abnormal signals appear in the white matter area of ​​the brain.

Level 2 moderate lesions: plaque-like abnormal signals have appeared in the white matter area of ​​the brain, or some point-like lesions have merged.

Grade 3 severe lesions: Lesions in the white matter area of ​​the brain have merged into large lesions.

At present, for patients with grade 1 white matter lesions, which are those found in most physical examinations without any symptoms, they can be temporarily observed and do not need any treatment. For patients with grade 2 and 3 white matter lesions, doctors recommend early intervention and timely treatment.

5. White matter lesions are currently incurable

White matter lesions are irreversible diseases and there is currently no specific cure. Therefore, the key to treatment is still to control the disease itself in the early stages and slow down the progression of the disease.

Clinically, the main treatment methods are stabilizing plaques, resisting platelet aggregation, improving cerebral blood circulation, and nourishing nerves to actively improve the patient's condition.

6. How to use traditional Chinese medicine to regulate

The main principle of TCM treatment of leukoencephalopathy is to improve brain blood circulation, treat both the symptoms and the root cause, and coordinate blood vessels, meridians, brain orifices, spleen, kidney, qi and blood. The method of replenishing qi, activating blood circulation and unblocking meridians is used to combine the principle of three connections and three supplements: unblocking blood vessels, unblocking meridians, unblocking brain orifices, tonifying spleen, tonifying kidney and tonifying brain. The method of replenishing qi, activating blood circulation, unblocking meridians and soothing liver is used for conditioning, and appropriate kidney tonification is given for possible kidney deficiency symptoms.

The human body is an organic whole. Taking into account the tonification, unblocking, treatment and prevention, and selecting the Chinese herbal medicine formula that replenishes qi, nourishes blood, activates blood circulation and dredges the meridians, it can help the body's meridians to be unblocked. This therapy also has the benefits of regulating qi and blood, ensuring the balance of qi and blood, and unblocking blocked blood vessels.

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7. How to prevent white matter lesions in advance?

Control blood pressure and blood lipid levels. Elevated blood pressure, blood lipid levels will increase the probability of atherosclerosis and increase the risk of pathological changes in brain white matter.

Control diabetes. If a patient suffers from diabetes, it will cause disorders in the body's sugar metabolism, causing the normal myelin phospholipids in the brain to be destroyed, leading to white matter degeneration.

It is encouraged to engage in more physical and brain exercises. For the elderly, the process of brain tissue deterioration can be delayed through reading, communication, calligraphy practice, etc.

In addition, encourage adequate sodium intake in daily life, adopt a Mediterranean diet (plenty of fruits and vegetables), control weight, quit smoking, and avoid excessive alcohol consumption.