Intracranial pressure: the invisible guardian of brain health

Author: Liu Baiyun, Chief Physician, Beijing Tiantan Hospital, Capital Medical University

Reviewer: Xiao Weizhong, Chief Physician, Peking University Third Hospital

Intracranial pressure, a little-known but crucial concept in daily life, is actually closely related to our brain health. Whether intracranial pressure is normal or not is directly related to the normal functioning of our brain. However, due to the low popularity of relevant knowledge about intracranial pressure, many people often lack sufficient understanding and vigilance when facing abnormal intracranial pressure.

1. Intracranial pressure: the key to maintaining brain health

Intracranial pressure refers to the pressure state maintained by the brain tissue, blood vessels and cerebrospinal fluid enclosed in the skull cavity. It is a necessary condition to ensure the normal function of the brain. This pressure state is maintained in a dynamic balance, just like blood pressure is maintained within a certain range to ensure blood circulation throughout the body. Intracranial pressure also needs to be maintained in a specific range to ensure the healthy functioning of the brain.

Under normal physiological conditions, the specific value of intracranial pressure usually fluctuates between 80-180 mmH2O, which is indirectly reflected by measuring the cerebrospinal fluid pressure. As a buffer medium for brain tissue, the cerebrospinal fluid's circulation dynamics are crucial to maintaining the stability of intracranial pressure. It undergoes a process of production, circulation, and absorption to maintain the stability of the intracranial environment.

2. Abnormal intracranial pressure: life alarm sounds

Abnormal intracranial pressure, whether too high or too low, is a sign of a pathological condition and requires our high attention.

High intracranial pressure is a common abnormal intracranial pressure phenomenon in clinical practice. When intracranial pressure increases, patients may experience symptoms such as headache, nausea and vomiting, and blurred vision. These symptoms are due to the compression of brain tissue caused by increased intracranial pressure, which in turn affects the normal function of the brain. If high intracranial pressure is not treated in time, the condition will further deteriorate, and the patient may experience serious symptoms such as decreased level of consciousness and coma, and even life-threatening.

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The symptoms of high intracranial pressure not only affect the patient's comfort, but may also indirectly lead to increased blood pressure by affecting emotions and psychological states. When the human body faces abnormal conditions such as increased intracranial pressure, it will activate a series of self-regulatory mechanisms. Among them, increased blood pressure is a measure taken by the body to increase blood supply to brain tissue. This process is called Cushing's reaction and is a manifestation of sympathetic hyperactivity.

Although low intracranial pressure is less common, it also needs our attention. Patients with low intracranial pressure may experience symptoms such as headache, dizziness, and nausea. Although these symptoms are not as serious as high intracranial pressure, they also need to be treated in time to prevent the condition from worsening.

3. Intracranial pressure monitoring and diagnosis

To accurately diagnose abnormal intracranial pressure, a series of examinations are required. Lumbar puncture is one of the main means of monitoring intracranial pressure. However, lumbar puncture also has certain risks, such as infection and bleeding. Therefore, before performing a lumbar puncture, the doctor needs to conduct a comprehensive assessment of the patient to ensure the safety of the operation.

Although lumbar puncture has an accuracy rate of up to 90%, its accuracy is affected by the circulation status of cerebrospinal fluid, especially when there is an obstruction in the cerebrospinal fluid circulation pathway. The flow of cerebrospinal fluid is blocked and the measured pressure may not truly reflect the actual intracranial pressure.

In order to overcome this limitation, doctors need to have a high degree of identification ability and make comprehensive judgments based on the patient's clinical symptoms, imaging examinations, etc. Imaging examinations can intuitively show changes in brain structure and provide a strong basis for diagnosis to ensure the accuracy of the diagnosis.

Treatment of abnormal intracranial pressure

First, the doctor will determine the specific cause of abnormal intracranial pressure through detailed examination and diagnosis. This may involve trauma, stroke, brain tumor, infection and other factors. After the cause is determined, the doctor will try to eliminate these potential pathogenic factors as much as possible, which is the fundamental way to reduce intracranial pressure.

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In terms of drug treatment, doctors will use dehydration drugs and diuretics, such as mannitol and furosemide, according to the specific conditions of the patients, to reduce the water content of brain tissue, reduce the volume of brain tissue, and thus reduce intracranial pressure. At the same time, giving sedatives and lowering body temperature are also commonly used treatment methods, which can slow down the basal metabolic rate, thereby reducing blood pressure, heart rate and intracranial pressure.

However, when non-surgical treatments cannot effectively control intracranial pressure, doctors may consider surgical intervention. Surgical treatments mainly include internal decompression and external decompression. Internal decompression is to surgically remove diseased tissue in the brain tissue, such as necrotic tissue or bleeding sites, to release intracranial space and reduce intracranial pressure. External decompression is to open the skull bone window to release the bulging brain tissue, thereby reducing intracranial pressure, which is called craniectomy.

In the treatment of increased intracranial pressure, cerebrospinal fluid drainage for decompression is an option worth considering. Cerebrospinal fluid drainage is an effective method to reduce intracranial pressure, including lumbar puncture catheter drainage and head burr hole external ventricular drainage. For increased intracranial pressure caused by cerebrospinal fluid circulation disorders and hydrocephalus, drainage is the best choice, which reduces intracranial pressure by releasing excess cerebrospinal fluid. However, it should be noted that cerebrospinal fluid drainage has certain risks, and its application requires strict control of indications. In some cases, such as intracranial hypertension crisis, lumbar puncture drainage is contraindicated because it may induce brain herniation.

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