Water flowing out of the ears is actually a sign of brain "leakage"? Learn about cerebrospinal fluid leakage in one article!

Tuchong Creative

A 45-year-old man living in Kawasaki, Japan, went to the hospital for treatment due to hearing loss. The doctor originally thought that he had otitis media with effusion in his right ear, but when observing the incision, he found a strange phenomenon: the exudation of fluid in the patient's middle ear coincided with the pulsation of his heartbeat. So the doctor immediately realized that the patient must have a brain "leakage". In fact, everyone has a lot of "water" in their brain, which maintains the normal functioning of the human body, but the problem of "leakage" should not be underestimated. Why does the brain leak "water"? What is the leaking "water"?

Cerebrospinal fluid is a colorless and transparent liquid. There are about 120-150 ml of it in the human brain. Its main component is water, and the rest is protein, glucose, various ions, vitamins and neurotransmitters. The existence of cerebrospinal fluid is still very necessary. First of all, it has a protective effect. The average weight of an adult's brain is about 1.5 kg, and the presence of cerebrospinal fluid and buoyancy reduces the weight borne by the brain by 10-15 times, so that the brain will not be damaged by its own weight. At the same time, cerebrospinal fluid continues to exist around the brain tissue and spinal cord tissue, and can also provide mechanical and immune protection for these tissues. Secondly, it also has the function of nutrition and waste removal. It plays the role of lymph in the central nervous system, supplies certain nutrients to brain cells, and transports away metabolic products of brain tissue. In addition, it also helps to maintain homeostasis. Cerebrospinal fluid participates in regulating intracranial pressure and keeps brain tissue in a suitable pressure environment. Through its osmotic pressure balance mechanism, it helps to stabilize the electrolyte and acid-base balance of brain tissue. Cerebrospinal fluid is mainly distributed in the ventricles, subarachnoid space and central canal of the spinal cord. The ventricles are the main storage places for cerebrospinal fluid, including the lateral ventricles, the third ventricle and the fourth ventricle; the subarachnoid space is the mixed area of ​​cerebrospinal fluid and the spinal cord cavity, and is the most widely distributed area of ​​cerebrospinal fluid; and the central canal of the spinal cord, as a pipe inside the spinal cord, is also filled with cerebrospinal fluid. It can also be said that cerebrospinal fluid is flexible and can settle in any corner. Its "life" is constantly flowing, all the way forward to the "recycling station". Cerebrospinal fluid is not only the "bodyguard" of the brain, but also its "nutritionist" and "cleaner", and it silently protects the health of its owner.

Since cerebrospinal fluid plays an important role in the human body, what happens when it leaks? And what causes it?

The most common clinical manifestation of CSF leak is the discharge of clear water from the nose.

Awake patients with CSF rhinorrhea may complain of salty fluid flowing out of the posterior nose, orbital congestion or subconjunctival hemorrhage, and increased fluid when lowering the head, bending over, exerting force, or coughing. In addition, headaches, decreased or loss of smell may occur, and more serious cases may cause intracranial infection. In fact, whether the cerebrospinal fluid will leak out is closely related to the integrity of the dura mater outside the arachnoid membrane. In the human brain, there are two large, special dura mater tissues, namely the "cerebriform falx" that separates the left and right hemispheres and is shaped like a sickle, and the "cerebellar tentorium" that separates the cerebrum and cerebellum. They are thick and dense, with little elasticity, and are essential for maintaining the structure of the human brain.

If the dura mater is damaged due to trauma or has developmental defects due to genetic factors, there is a high probability of brain "leakage".

According to the cause, the clinical classification of cerebrospinal fluid leakage can be divided into traumatic cerebrospinal fluid leakage, postoperative cerebrospinal fluid leakage and idiopathic cerebrospinal fluid leakage; according to the outflow site of cerebrospinal fluid leakage, it can be divided into cerebrospinal fluid rhinorrhoea, cerebrospinal fluid otorrhea and wound cerebrospinal fluid leakage. Among them, about 80% of cerebrospinal fluid leakage is traumatic cerebrospinal fluid leakage, which is caused by skull fracture caused by head trauma. The incidence of cerebrospinal fluid leakage in patients with various types of head trauma is 2%, and 30% of patients with skull base fracture will have cerebrospinal fluid leakage; postoperative cerebrospinal fluid leakage is caused by the failure of the dura mater to be tightly sutured after brain and spinal cord surgery, and the wound is open due to various reasons, resulting in cerebrospinal fluid leakage to the body, such as the incidence of cerebrospinal fluid leakage after craniotomy is 4%-32%; idiopathic cerebrospinal fluid leakage is due to the decline of biomechanical properties of the meninges, and rupture and bleeding of cerebrospinal fluid leakage occurs under various inducements, such as hydrocephalus, tumors and benign intracranial hypertension.

It can be seen that the symptoms of cerebrospinal fluid leakage are still very obvious, but why do misdiagnoses still occur? First, because some of the symptoms are similar to cervicogenic headaches, and cervicogenic headaches are extremely common in clinical practice, low intracranial pressure cerebrospinal fluid leakage is very easy to be misdiagnosed. If it is treated according to cervical spondylosis or migraine, the best treatment time is often delayed, and it is easy to develop subdural hematoma or even brain hernia, which is life-threatening. Second, because cerebrospinal fluid leakage is more common in the nose, at this time, the cerebrospinal fluid will be mixed with the secretions in the nose and it is difficult to distinguish. However, a protein called beta-2 transferrin is almost only present in cerebrospinal fluid, so it is possible to determine whether cerebrospinal fluid has leaked into the nasal cavity by detecting whether this protein is present in the nasal mucus.

With the gradual deepening of our understanding of cerebrospinal fluid leakage, and through MRI scans of the entire brain or spine, doctors are discovering more and more cases of cerebrospinal fluid leakage. At the same time, in our daily lives, we should improve our health awareness and detect problems early. For example, if you find reddish liquid flowing out of the nasal cavity or ear canal, or colorless liquid flowing out of the nasal cavity that does not form a crust after drying, and the flow increases after you lower your head and exert force, you may suspect cerebrospinal fluid leakage. When cerebrospinal fluid leakage and other related problems do occur, you can take absolute bed rest, use gravity to move the brain tissue to the base of the skull, and allow the meninges to gradually form adhesions to close the rupture in the meninges, promoting natural healing. If the initial condition is serious, you should undergo cerebrospinal fluid leakage repair surgery as soon as possible.
In a word, too much "water" in the brain is not good, and too little is not good either. As the saying goes, nothing is worse than just right.

This article is a work supported by the Science Popularization China Creation Cultivation Program

Author: Chen Dingxin

Reviewer: Gui Yaxing, Chief Physician, Department of Neurology, Shanghai First People's Hospital

Produced by: China Association for Science and Technology Department of Science Popularization

Producer: China Science and Technology Press Co., Ltd., Beijing Zhongke Xinghe Culture Media Co., Ltd.