There is a folk saying that a big head is smart. This may just be an illusion of the official-oriented China, so that the people have seen more fat-headed officials Oh! Great scientists, artists, industrialists, etc. have big heads and small heads, which are related to intelligence, life experience, opportunities, effort and many other factors, and intelligence originally has nothing to do with the size of the head. However, children with abnormally large or rapidly growing head circumference, bulging fontanelle, separate skull sutures, and dilated scalp blood vessels need to be examined and judged by a doctor at a hospital. Other manifestations of hydrocephalus include increased pressure in the anterior cranial fossa, which causes the eyes to turn down and protrude outward, exposing the upper white sclera and making the child’s eyes look like “sunset”; there may also be mental depression, drowsiness, or restlessness, easy vomiting, frequent convulsions, paralysis, difficulty walking, etc. Some clinical manifestations of hydrocephalus are not obvious, but only hydrocephalus affects the intellectual development of children, children with large heads, poor intelligence, poor walking, language fluency, poor urine control, should go to the hospital for examination, if early detection, timely treatment, intelligence can still be restored to normal. Therefore, as a parent of an infant, you should observe carefully and see a doctor promptly if you find any of the above symptoms in your child.
Overview: Hydrocephalus is a pathological condition in which the secretion, circulation or absorption process of cerebrospinal fluid is impaired, resulting in an increase in intracranial cerebrospinal fluid and causing abnormal enlargement of the ventricles and/or subarachnoid space. The basic feature is that the excess cerebrospinal fluid produces increased intracranial pressure, thus enlarging the space occupied by normal cerebrospinal fluid. If hydrocephalus occurs before the closure of the cranial suture, the enlargement of the skull is abnormal and significant. Hydrocephalus that is present at birth is called congenital hydrocephalus, and hydrocephalus that has a definite cause after birth is called acquired (acquired) hydrocephalus. The relative increase in cerebrospinal fluid volume due to the enlargement of the ventricles and subarachnoid space as a result of atrophy of the brain parenchyma itself for various reasons does not fall into the category of hydrocephalus.
Etiology of pediatric hydrocephalus.
One: Infection. Fetal intrauterine infections such as various viruses, protozoa and syphilis spirochete infectious meningitis are not controlled early enough, and the proliferating fibrous tissue blocks the circulatory orifice of cerebrospinal fluid, or fetal intracranial inflammation can also occlude the cerebral pool, subarachnoid space and arachnoid granule adhesions.
Second: congenital malformations. Such as stenosis of the midbrain aqueduct, diaphragm formation or atresia, atresia malformation of the interventricular foramen, median foramen of the fourth ventricle or lateral hollow atresia, cerebrovascular malformation, spina bifida, and submicrocephalic tonsillar herniation.
III: Tumors. Can obstruct any part of the cerebrospinal fluid circulation, more commonly seen near the fourth ventricle, or choroid plexus papilloma.
IV: Hemorrhage. Fibroplasia caused by intracranial hemorrhage, malabsorption of intracranial hemorrhage from birth injury, etc.
Classification.
It is customary to clinically classify hydrocephalus into two types: communicative and obstructive, which is based on anatomic etiology. Hydrocephalus in which the ventricular system is open to the subarachnoid space but is caused by hypersecretion of the choroidal plexus or impaired absorption of arachnoid granules is called traffic hydrocephalus. Hydrocephalus caused by obstruction of circulatory pathways within the ventricular system is called obstructive hydrocephalus, and obstructive hydrocephalus is more common in clinical practice. There are many other ways to classify hydrocephalus, which are not yet uniform. According to the time of pathogenesis, it can be divided into congenital and acquired hydrocephalus; according to the speed of onset, it can be divided into acute and chronic hydrocephalus; according to the increase of intracranial pressure or not, it can be divided into high pressure hydrocephalus and positive pressure hydrocephalus; according to the different sites of occurrence, it can be divided into intracerebral hydrocephalus and extracerebral hydrocephalus. These classifications are intersecting, and the same case can be attributed to different types.
Pathogenesis.
Under normal conditions, cerebrospinal fluid is continuously circulated and metabolized in the ventricular system and subarachnoid space, and its secretion and absorption rates are in dynamic balance, thus maintaining the relative stability of intracranial cerebrospinal fluid volume. Cerebrospinal fluid is mainly produced from the choroid plexus in each ventricle, especially the lateral ventricles, accounting for 80%-85%, with a few leaks from the ventricular epithelium, producing 0.3-0.35 ml of cerebrospinal fluid per minute in children (average 20 ml per hour). After cerebrospinal fluid is generated in the ventricles, it circulates at a liquid hydrostatic pressure of about 1.47 kPa (150 mmH2O). The cerebrospinal fluid generated in the left and right lateral ventricles flows into the third ventricle via the interventricular foramen, and together with the cerebrospinal fluid generated in the third ventricle, flows into the fourth ventricle via the midbrain aqueduct, and then together with the cerebrospinal fluid generated in the fourth ventricle, flows out through the median foramen and two lateral foramina of the fourth ventricle and enters the cerebellar medullary pool in the subarachnoid space. The cerebrospinal fluid is then circulated upward to the brain surface via the basal pool and finally absorbed passively through the arachnoid villi (granules) into the dural venous sinus (superior sagittal sinus) which is the main route of cerebrospinal fluid absorption. A small portion of cerebrospinal fluid enters the subarachnoid space of the spinal cord and is absorbed into the bloodstream by the arachnoid villi of the spinal veins. Another small amount of cerebrospinal fluid is absorbed through the capillaries of the subarachnoid space in the ventricular epithelium of the ventricles, the lymphatic vessels of the meninges, and the arachnoid sheath at the cranial exit of the cerebral nerves. Cerebrospinal fluid is continuously returned to the veins via the above pathways, creating a circulation of cerebrospinal fluid.
Hydrocephalus can occur in three ways: (1) excessive production of cerebrospinal fluid, which is rare; (2) impaired absorption of cerebrospinal fluid, which is also rare; and (3) impaired circulation of cerebrospinal fluid, which is the case in most cases of hydrocephalus.
Complications
1. Brain degeneration, brain development disorders, central paralysis of the limbs, especially the lower limbs, often with intellectual changes and developmental disorders.
2. Optic nerve compression and atrophy, which may lead to blindness.
3. It is often complicated by deformities in other parts of the body.
If hydrocephalus in children is treated with external shunt surgery, the following complications may occur.
Obstruction of the shunt system is the most common complication and can occur at any time from the operating room to several years after surgery, most commonly at 6 months postoperatively.
Infection Infection remains one of the major complications after cerebrospinal fluid shunt surgery. Infection can cause intellectual impairment, formation of compartmentalized cavities within the brain, and even death in patients. Despite decades of efforts, many medical centers still report infection rates of 5% to 10%. Infections are classified according to the site of involvement: wound infections, meningo-ventriculitis, peritonitis, and shunt infections. Most infections occur within 2 months after shunt surgery.
3. Excessive or insufficient shunts
4. slit ventricle syndrome The incidence of slit ventricle syndrome (slit ventricle syndrome) is 0.9% to 55%, which can occur in patients with traffic or non-traffic hydrocephalus after surgery.
5. Other complications: (1) complications at the ventricular end of the brain (2) complications at the ventral end of the brain (3) epilepsy.
Clinical presentation.
Clinical symptoms are not consistent and are related to the age of appearance of the pathological changes of hydrocephalus, the severity of the disease and the duration of the disease.
1. cephalic changes Mainly seen in infants and young children with onset, mostly congenital hydrocephalus. The head is progressively and abnormally enlarged, disproportionate to the development of the whole body. The fontanelle is enlarged and full, the cranial suture is split, and the skull is thin and soft. There is a “broken pot sound” (Macewen’s sign) on head percussion, and in severe cases, there is a trembling sensation on percussion. The forehead protrudes forward and the roof of the orbit sinks under pressure, the eyeballs push down, so that both eyes look down and the sclera above is exposed, and the lower part of the eyeballs often fall below the lower eyelid, showing the so-called “setting sun” sign, which is a unique sign of congenital hydrocephalus. The cranial transillumination test can be positive in infants with hydrocephalus, and the enlarged occipital restricted transillumination circle suggests Dandy-Walker malformation, while extensive cranial transillumination is seen in severe hydrocephalus.
In infants and young children, the general symptoms of increased intracranial pressure are not obvious, but the bulging of fontanelle and increased tension of scalp veins can be seen. When hydrocephalus progresses faster, recurrent vomiting may also occur. In larger children with hydrocephalus whose fontanelles and cranial sutures have been closed, the symptoms often manifest as increased intracranial pressure (headache, vomiting and optic papilledema). The headache is often aggravated when the child rests in bed for a long time, so the headache often disappears in the morning after getting up and moving around, probably because the activities prompt the cerebrospinal fluid to pass through the stenosis and make the symptoms less severe. When hydrocephalus develops slowly, ventricular enlargement and intracranial pressure increase slowly, it may only show headache, change of personality and mood, or the appearance of spreading nerve palsy and inward slanting of the eyes; however, in the late stage of the disease, there is mostly intracranial pressure increase.
3. Neurological dysfunction Except for those secondary to some intracranial tumors, most hydrocephalus has no obvious neurological localization signs. However, as the disease progresses, infants or children may develop hypokinesia, etc. Severe hydrocephalus can cause visual loss or even blindness due to compression of the occipital cortex by the extremely enlarged occipital horn of the ventricle or compression of the optic cross by the pulsation of the enlarged third ventricle. Primary optic nerve atrophy is seen in the fundus of the eye. When the enlargement of the fourth ventricle is obvious, manifestations of cerebellar or brainstem involvement may occur, as well as symptoms such as supraocular visual impairment in both eyes and damage to the cone bundle. In the late stage of hydrocephalus or in severe cases, growth disorders, mental retardation, spastic paralysis of limbs and consciousness disorders may appear.
In addition to the above-mentioned manifestations, children with hydrocephalus may also exhibit mental inactivity, sluggishness, and irritability. In infants and young children, the head is enlarged and overweight, so they have poor head and neck control and are usually unable to sit or stand. Some patients have convulsive seizures. If the anterior part of the third ventricle and the inferior optic thalamus and funiculus are involved, various endocrine dysfunctions may occur, such as precocious puberty or backwardness and short growth.
5. Symptoms of the primary disease, such as supraoptic inability in pineal tumors and ataxia in cerebellar earth tumors.
Diagnosis.
The clinical diagnosis of hydrocephalus in infants and children can be made based on features such as rapid enlargement of the skull and its characteristic appearance and morphology; however, further neuroimaging (cranial CT or MRI) is needed to confirm the diagnosis. As the age of the child increases or due to the slow progression of hydrocephalus, the cranial changes may be atypical, and the diagnosis should be made based on other clinical manifestations and with the help of relevant auxiliary examinations, and attention should be paid to finding the primary cause in the diagnosis, and the site of obstruction should be clarified if the hydrocephalus is obstructive.
Differential diagnosis.
In infants care should be taken to differentiate from the following.
1. immature infants with rapid cranial enlargement, some resembling hydrocephalus, but not large ventricles.
2. rickets The cranial enlargement is mostly square with other symptoms of rickets.
3. Chronic subdural hematoma Often there is a history of head trauma (sometimes the history of trauma is not obvious), vomiting, slower cranial enlargement, CT shows widening of the subdural cavity, and more orange or yellow fluid in the subdural puncture.
4. intracranial occupying lesions such as tumors, abscesses, etc.
Auxiliary examination
Non-invasive cranial CT and MRI are the most commonly used methods with the most reliable results. They can clarify the diagnosis of hydrocephalus and further understand the cause, type, obstruction site and degree of ventricular enlargement of hydrocephalus, so as to choose the appropriate treatment measures. In particular, cranial MRI is superior in showing the site of obstruction of cerebrospinal fluid pathways and the cause of the obstruction.
As for cranial ultrasound, it can be used for intrauterine diagnosis of fetal hydrocephalus and provide a basis for whether the pregnancy is terminated.
Treatment.
Surgery is the main treatment for hydrocephalus, regardless of the cause, and should be used promptly for progressive hydrocephalus. Surgical treatment can remove the cause or reestablish the cerebrospinal fluid circulation pathway, but the results of surgery have not yet reached a satisfactory state. For children with early, slowly developing hydrocephalus or those not suitable for surgical treatment, pharmacological treatment is the mainstay, with dehydration or diuretics and drugs that inhibit cerebrospinal fluid secretion being used as appropriate. Acquired hydrocephalus also requires treatment of the primary cause.
1. Surgical treatment
(1) Cerebrospinal fluid shunt: The purpose is to achieve cerebrospinal fluid shunt by reconstructing the cerebrospinal fluid circulation pathway. The development of pediatric hydrocephalus shunts has not only increased the survival rate of children with hydrocephalus, but also enabled 70% of children to maintain basically normal intelligence. There are two types of shunts, intracranial and extracranial, depending on the endpoint of the shunt. Intracranial cerebrospinal fluid shunts are suitable for obstructive hydrocephalus, such as lateral ventricle-cerebellar medullary pool shunt and ventricle-superior sagittal sinus shunt (anastomosis). Extracranial cerebrospinal fluid shunts are used for all types of hydrocephalus. There are many methods, including surgery to drain cerebrospinal fluid to the cardiovascular and surgery to drain it to other organs or body cavities, with the former commonly used for ventriculo-atrial shunts and the latter for lateral ventriculo-abdominal shunts, which can avoid the disadvantages of other shunts and can be used in both traffic and non-traffic hydrocephalus cases.
The outcome of the shunt depends not only on the procedure itself, but also on the thickness of the preserved cerebral cortex and the presence of other combined malformations in the pediatric population before surgery. Although the rapid growth of head circumference stops after shunt surgery. However, the size of the ventricles and the thickness of the cerebral cortex need to be regularly monitored by cranial CT or MRI to prevent persistent mild intracranial hypertension from compressing the cerebral cortex and causing mental retardation. Frequent postoperative follow-up will also facilitate timely detection of shunt incompetence, whether the distal shunt is long enough, or whether there is secondary infection, so that appropriate treatment can be given. A recent study found that brain damage caused by the shunt itself or postoperative complications (such as infection, subdural hematoma, inadequate or excessive shunts, shunt obstruction, fracture, too short, etc.) can cause shunt failure; they can also lead to seizures, which are more likely to occur in those who undergo shunts within 2 years of age, with an incidence of 20% to 50%. Therefore, minimally invasive ventriculostomy under neuroendoscopy is a more reliable method to treat obstructive hydrocephalus.
(2) Minimally invasive ventriculostomy under ventriculoscopy: According to the obstruction site of hydrocephalus, lateral ventriculostomy, interventricular foramen ovale and triple ventriculostomy can be chosen. Transparent septal stoma is suitable for lateral ventricular hydrocephalus caused by one-sided interventricular foramen obstruction; interventricular foramen stoma is suitable for bilateral lateral ventricular hydrocephalus caused by bilateral interventricular foramen obstruction; triple ventriculostomy stoma is suitable for hydrocephalus caused by obstruction of the middle cerebral aqueduct, median foramen and lateral foramen of the four ventricles. The advantages of ventriculoscopic minimally invasive ventriculostomy are: A less invasive, also only a small hole needs to be drilled in the head; B close to the physiological circulation of cerebrospinal fluid; C less chance of further complications and sequelae after successful surgery; C no exogenous implants. The disadvantages are: it must be operated by an experienced surgeon.
(3) Surgery to reduce cerebrospinal fluid production: mainly choroid plexotomy or electrocautery. It has been rarely used because of poor results.
(4) Surgery to remove the cause: such as removal of intracranial tumors, abscesses and other occupying lesions, and restoration of cerebrospinal fluid circulation pathways. It is rare that the cause of obstruction due to congenital developmental malformations can be removed by surgery. For example, for Dandy-Walker malformation, a median foraminotomy of the fourth ventricle is feasible; for Arnold-Chiari malformation, posterior cranial fossa and upper cervical laminectomy and decompression are feasible. For Arnold-Chiari malformation, posterior cranial fossa and upper cervical laminectomy and decompression are possible.
The aim is to temporarily reduce the secretion of cerebrospinal fluid or increase the discharge of water from the body (diuretic), and reduce intracranial pressure mainly with acetazolamide (acetazolamide) 25-50mg/(kg・d), which reduces the secretion of cerebrospinal fluid by inhibiting Na+-K+ATPase in the epithelial cells of the choroid plexus; or with dehydrating agents such as mannitol, diuretics such as hydrochlorothiazide (dihydrochlorothiazide), etc., to increase the excretion of water. The efficacy of these drugs is generally not significant or only mildly temporary, and they should not be used long-term. For patients with arachnoid adhesions, dexamethasone can be tried orally, intramuscularly or intrathecally. In patients with seizures, antiepileptic drugs are given.
Prevention
1. Strengthen early prenatal diagnosis and early termination of pregnancy to prevent the birth of children with hydrocephalus.
Early prenatal diagnosis of children with hydrocephalus is an important way to prevent the birth of children with hydrocephalus. As obvious hydrocephalus can be detected by ultrasound at 12 to 18 weeks of gestation, it is necessary to strengthen the application of ultrasound in prenatal diagnosis, early termination of pregnancy to prevent the birth of children with hydrocephalus and reduce the birth rate of congenital hydrocephalus.
According to relevant data, the risk of hydrocephalus in fetus can be increased by the increase of maternal births. The incidence of hydrocephalus increases significantly in those with more than two births. Therefore, to promote the knowledge of eugenics and reduce the number of births is one of the ways to prevent hydrocephalus children.
3. Promote appropriate age of childbirth From relevant data, the incidence of hydrocephalus malformation has a tendency to increase with the age of pregnant women, generally the lowest incidence in the group of 25-29 years old, but the difference is not significant, after 30 years old, the incidence has a tendency to increase. Therefore, it is meaningful to promote the birth of children at an appropriate age to prevent the occurrence of hydrocephalus.
4. Strengthen eugenics education, improve the quality of population culture According to relevant statistics, the occurrence of hydrocephalus is related to the education level of pregnant women. The lower the literacy of pregnant women, the higher the incidence, and the illiterate and semi-literate offspring have the highest rate of disease. Therefore, in order to improve the health quality of the population, we should first improve the cultural quality of the population, in order to enhance the public’s acceptance of eugenics education and self-care awareness.
5. Safe delivery, prevent asphyxia and birth injury When pregnant women give birth, they must give birth in a hospital with good environmental conditions, do not delay the delivery process, be careful to prevent perinatal asphyxia and birth injury. This is an important part of preventing the occurrence of perinatal hydrocephalus children.