Patients or family members often ask questions about hydrocephalus, but due to limited clinic time, there is simply no time to explain in detail, so we will now summarize the knowledge of the disease and common problems. Since we are usually busy with surgery and have limited time, we will gradually improve this introduction.
The concept of hydrocephalus
In layman’s terms, the brain and spinal cord are like tofu brains that are raised in water (cerebrospinal fluid). The brain and spinal cord are protected by the skull and vertebrae, which form the cranial cavity and vertebral canal, respectively, and are connected to each other.
The cerebrospinal fluid is not “stagnant water”, but “living water” that is constantly produced and absorbed, maintaining a dynamic balance (about 500 ml per day) and maintaining a certain pressure level in the cranial cavity and vertebral canal, which is too high (high cranial pressure) or too low (low cranial pressure). High (high cranial pressure) or low (low cranial pressure) pressure levels can cause varying degrees of damage to brain and spinal cord tissues, and timely restoration of appropriate pressure levels can restore the damage, but severe damage will be difficult to restore and even cause death.
Normal cerebrospinal fluid pressure levels.
80-180 mm water column for adults and 50-100 mm water column for children.
Above 200 mm water column is considered high cranial pressure. Cerebrospinal fluid pressure is usually measured by lumbar puncture into the spinal canal (the intracranial cerebrospinal fluid is connected to the intracranial cerebrospinal fluid)
The main processes of cerebrospinal fluid circulation.
It is continuously produced within the ventricular system from the arterial vessels via the choroid plexus tissue, flows through the ventricular outlet to the subarachnoid space (the space between the brain surface and the skull, and the space between the spinal cord surface and the vertebrae), is then absorbed through the arachnoid granules into the venous vessels, and so on in a continuous cycle to keep the cerebrospinal fluid components up to date. The left side of the diagram below shows the pattern and the right side shows the MRI sagittal section (specific pathways of cerebrospinal fluid circulation: intracerebroventricular choroid plexus produces from lateral ventricles, interventricular foramen, triventricular ventricles, aqueduct, tetraventricular ventricles, exit of tetraventricular ventricles, subarachnoid space, and sagittal sinus veins). Since the cranial cavity and vertebral canal are closed cavities formed by bony tissues and their volume is constant in adults, excessive accumulation of cerebrospinal fluid in these closed cavities inevitably causes compression of the brain and spinal cord tissues, resulting in damage to the brain and spinal cord tissues due to pressure, most notably brain damage.
Clinical manifestations
Acute development: Headache accompanied by nausea and vomiting, which continues to progress leading to unconsciousness and coma.
Chronic development: The symptoms are more complex, especially in the early stage of the disease, and are very easy to be misdiagnosed because of the atypical symptoms.
Brain symptoms: common include chronic recurrent headache, dizziness, lightheadedness, memory loss, decreased academic performance of students, blurred vision, double vision, fondness for sleep, unstable walking, urinary incontinence, mental disorders, epilepsy, fainting, etc.
Gastrointestinal symptoms: recurrent nausea, vomiting, loss of appetite, etc.
Imaging tests.
1.Cranial CT
2.Cranial magnetic resonance
Hydrocephalus is mainly manifested as enlargement of the ventricular system in the imaging examination. The ventricular system includes the left and right ventricles, the three ventricles, and the four ventricles (see the figure below).
The left side shows the size of the ventricular system in a normal person, and the black part indicated by the arrow is the intraventricular cerebrospinal fluid. The right image shows a patient with subarachnoid hemorrhage from an aneurysm who developed delayed hydrocephalus after interventional embolization of the aneurysm (significant enlargement of the ventricular system)
Common names of hydrocephalus
1. Obstructive hydrocephalus.
Caused by obstruction of the ventricular system, such as inflammatory adhesions at the ventricular outlet, obstruction of the outlet by intraventricular tumors, and compression of the ventricular outlet by lesions around the ventricular outlet.
Common tumors.
Tumors of the four ventricles (ventricular meningioma, medulloblastoma, choroid plexus papilloma), lateral ventricular tumors (ventricular meningioma, meningioma, central neuroblastoma), extra-ventricular tumors such as pineal area tumors, glioma, auditory neuroma, etc.
2. Traffic hydrocephalus (absorption disorder hydrocephalus).
No obstruction in the ventricular system, obstruction in the subarachnoid space outside the exit of the four ventricles.
Common causes :
After intracerebral infection, after craniocerebral trauma, after craniocerebral surgery (such as cerebral hemorrhage, brain tumor, post-operative aneurysm). It is especially likely to occur after craniocerebral trauma surgery or after cerebral hemorrhage, mostly 1 month or more after trauma, hemorrhage or surgery. Often the patient starts to recover very well after surgery, and after a while the patient’s condition becomes worse again without obvious reasons, which is often caused by delayed hydrocephalus occurrence, and should promptly go to the hospital to review the cranial MRI or cranial CT to clarify.
3, normal pressure hydrocephalus (referred to as “positive pressure hydrocephalus”, or “normal pressure hydrocephalus”).
Because the pressure of cerebrospinal fluid measured by lumbar puncture is not high, and the same as normal people, so the name. It is common in middle-aged and elderly people, and the cause is unknown in many cases. Traffic hydrocephalus is also often measured with low pressure, which is also normal pressure hydrocephalus. Typical manifestations are mental abnormalities or mental decline, unstable walking, and urinary incontinence (especially at night when urine tends to get onto the pants). Common manifestations are chronic on-again, off-again headaches or dizziness, gradual loss of vision, and may be accompanied by nausea or vomiting.
Hydrocephalus treatment methods
1.Remove the cause of the disease.
If hydrocephalus is caused by ventricular tumor obstruction, the obstruction will be lifted naturally after removal of ventricular tumor.
2.Ventriculoperitoneal shunt.
It is suitable for postoperative traffic hydrocephalus, normal pressure hydrocephalus, obstructive hydrocephalus caused by adhesions at the outlet of the four ventricles or obstruction at the outlet of the three ventricles. Uses a tube buried under the skin to drain from the lateral ventricles into the abdominal cavity, where the cerebrospinal fluid is absorbed. It is the most common treatment for hydrocephalus (will be described specifically in another article).
3. Triventricular base fistulotomy.
It is especially suitable for obstructive hydrocephalus caused by adhesions at the outlet of the four ventricles or obstruction at the outlet of the three ventricles. It is done by using a ventriculoscope (neuroendoscope) to make an outlet at the base of the three ventricles to allow cerebrospinal fluid to enter the subarachnoid space.