Hydrocephalus is an increased accumulation of cerebrospinal fluid in the cerebrospinal fluid system of the brain. Disease accompanies many congenital and acquired neurological diseases. Clinically, it is manifested by signs of increased intracranial pressure (headache, nausea, pressure on the eyes), symptoms of compression of brain structures (vestibular ataxia, visual disturbances, mental disorders, epi-attacks) and symptoms characteristic of the disease that caused it. The diagnosis includes radiography of the skull, ophthalmological examinations, Echo-EG (in infants — neurosonography), MRI or CT of the brain. Surgical treatment allows correcting congenital anomalies of the cerebrospinal fluid system, removing intracranial formations that violate the cerebrospinal fluid circulation, and adjusting the outflow of cerebrospinal fluid from the cranial cavity.
Hydrocephalus literally means “dropsy of the head”. In modern neurology, this is a common clinical syndrome that can occur in many diseases, congenital anomalies or post-traumatic brain conditions. The occurrence is associated with various disorders in the cerebrospinal fluid system. People of any age are susceptible to the appearance of hydrocephalus. Hydrocephalus can occur in newborns, have a congenital character, develop in children and adults, accompany atrophic processes occurring in the brain of the elderly. However, it is most often found in pediatric practice.
3 pathological mechanisms lead to the accumulation of an excessive amount of cerebrospinal fluid in the cerebrospinal fluid system of the brain: the production of an excessive amount of cerebrospinal fluid, a violation of its absorption or a disorder of cerebrospinal circulation. Hydrocephalus may be based on one of these mechanisms or a combination of them. The causes that cause disorders in the work of the cerebrospinal fluid system can act during intrauterine development and cause congenital hydrocephalus or affect the brain after birth and cause the appearance of so-called acquired hydrocephalus. The causes include:
1. Congenital hydrocephalus:
- malformations of the cerebrospinal fluid system (atresia of the holes of Mazhandi and Lushka
- defects in the structure of the subarachnoid space
- sylvian aqueduct stenosis, Dandy-Walker syndrome, etc.)
- craniovertebral anomalies (Chiari anomaly, congenital basilar impression)
- intrauterine infections (toxoplasmosis, congenital syphilis, cytomegaly, rubella), birth trauma.
2. Acquired hydrocephalus:
- inflammatory processes in the brain and its membranes (encephalitis, arachnoiditis, meningitis)
- traumatic brain injuries
- vascular disorders (hemorrhages in the ventricles, hemorrhagic stroke or intracerebral hematomas with a breakthrough of blood into the ventricles).
- ventricular germination and compression of the cerebrospinal fluid pathways against the background of colloidal cyst of the III ventricle and intracerebral tumors (astrocytomas, germinomas, ganglioneuromas, etc.). At the same time, normal circulation of the cerebrospinal fluid and its outflow from the cranial cavity is disrupted.
Separately, there is an atrophic (substitutive) form, which occurs due to post-traumatic death or age-related atrophy of brain tissues. In this case, the cerebrospinal fluid fills the space that is formed inside the skull as a result of a decrease in the volume of the brain. Atrophic hydrocephalus in old age can develop against the background of impaired blood supply to the brain with atherosclerosis of cerebral vessels, hypertension, diabetic macroangiopathy.
Normally, CSF (cerebrospinal fluid) is produced by vascular plexuses of the brain ventricles communicating with each other. The largest amount of it is formed in the lateral ventricles, from where the liquor enters the III ventricle, and from it through the Sylvian water supply to the IV ventricle. Then the cerebrospinal fluid enters the subarachnoid (subarachnoid) space, which extends over the entire surface of the brain, and in the caudal direction passes the area of the craniovertebral junction and further surrounds the spinal cord throughout its entire length. The cerebrospinal fluid located in the subarachnoid space is constantly absorbed by the arachnoid (arachnoid) membrane of the spinal cord and brain and enters the blood. The above etiological factors that disrupt the production, movement and absorption of cerebrospinal fluid, lead to its excessive accumulation and the occurrence of hydrocephalus.
According to the etiological principle, congenital and acquired hydrocephalus are distinguished. According to the mechanism of occurrence, hydrocephalus is classified into open and closed forms.
Open hydrocephalus is associated with hyperproduction of cerebrospinal fluid or a violation of its absorption in normal cerebrospinal fluid circulation.
Closed hydrocephalus is caused by a violation of the outflow of cerebrospinal fluid due to compression, partial or complete obturation of any part of the cerebrospinal fluid system of the brain.
Depending on where the excessive accumulation of cerebrospinal fluid occurs, internal and external hydrocephalus are distinguished. Internal hydrocephalus is accompanied by an accumulation of cerebrospinal fluid in the ventricles of the brain. External hydrocephalus is characterized by an excess of cerebrospinal fluid in the subarachnoid and subdural space.
According to the peculiarities of the course, hydrocephalus is classified as acute, subacute and chronic. Acute hydrocephalus is characterized by rapid development, in which decompensation occurs a few days after the onset of the first signs of the disease. Subacute hydrocephalus develops within a month, and chronic hydrocephalus develops for more than six months.
Of great clinical importance is the division of hydrocephalus into stabilized (compensated) and progressive (increasing).
Stabilized hydrocephalus does not increase and usually proceeds with normal cerebrospinal fluid pressure.
Progressive hydrocephalus is characterized by an aggravation of symptoms, accompanied by an increase in cerebrospinal fluid pressure, poorly amenable to conservative therapy and leads to atrophy of brain tissues.
Hydrocephalus in adults
The accumulation of an excessive amount of cerebrospinal fluid in a limited space of the cranial box leads to an increase in intracranial pressure, which causes the most typical symptoms. In adults and older children , these include: intense headache, nausea, vomiting, a feeling of pressure on the eyeballs that cannot be removed by analgesics. These symptoms may occur acutely or increase gradually, having a transient character at the beginning of the disease. Atrophic hydrocephalus often proceeds without signs of increased intracranial pressure and is detected only with additional examination of the patient.
In most cases, hydrocephalus is accompanied by neurological symptoms, which is caused by both compression of brain structures by expanded cerebrospinal spaces, and the underlying disease that causes the development of this disease. Vestibular and visual disturbances are most often noted in hydrocephalus. The first include vestibular ataxia, manifested by dizziness, unsteadiness of gait, noise in the ears and head, nystagmus. From the side of vision, there may be a significant decrease in visual acuity, loss of certain areas of the visual fields, stagnant discs of the optic nerves; with a prolonged course of hydrocephalus, optic nerve atrophy may develop.
Hydrocephalus can occur with disorders of the motor and sensory sphere: paresis and paralysis, increased tendon reflexes and muscle tone, decreased or complete loss of all types of sensitivity, the formation of spastic contractures of the extremities. Occlusive hydrocephalus, caused by impaired circulation of the cerebrospinal fluid in the posterior cranial fossa, is characterized by symptoms of cerebellar ataxia: impaired coordination and gait, large-scale disproportionate movements, changes in handwriting, etc.
In some cases, hydrocephalus is accompanied by mental disorders, which in adults are more often manifested by disorders of the emotional-volitional sphere: emotional instability, neurasthenia, causeless euphoria with a rapid transition to a state of indifference and apathy. With a sharp increase in intracranial pressure, aggressive behavior is possible.
Hydrocephalus in children
In children, due to the great malleability of the skull bones, there is no increase in intracranial pressure, hydrocephalus is accompanied by an increase in the size of the skull. In newborns and young children, hydrocephalus is characterized by an excessively large head size, swelling of the scalp veins, tension and lack of pulsation of the large fontanel, edema of the optic nerve discs.
Often there is a symptom of the “setting sun” – a restriction of the movements of the eyeballs upward. There may be a divergence of the sutures of the skull. Tapping on the skull is accompanied by a characteristic sound (a symptom of a “cracked pot”). In children of the first year of life, hydrocephalus leads to a lag in development. They later begin to hold their heads, roll over, sit and walk.
Children who have pronounced hydrocephalus are distinguished by the spherical shape of the head, its too large size, deep-set eyes, protruding ears, thinning of the scalp. There may be a decrease in vision, an increase in muscle tone in the lower extremities, disorders of the cranial nerves. Unlike adults, in childhood hydrocephalus is more often accompanied not by emotional and volitional disorders, but by intellectual insufficiency.
Children with hydrocephalus are usually sedentary and obese. They are apathetic, uninitiative, do not have the attachment to relatives characteristic of their peers. A decrease in the degree of hydrocephalus often leads to an increase in the intellectual abilities and activity of the child.
In adolescence, hydrocephalus often occurs acutely against the background of an infectious disease, mental or physical trauma. At the same time, it is accompanied by intense headache, repeated vomiting, bradycardia. Possible attacks of loss of consciousness, sometimes convulsive seizures. In some cases, episodic psychoses with hallucinatory or delusional syndrome are observed.
The clinical symptoms of hydrocephalus are usually so characteristic that they allow the neurologist to suspect its presence at the first examination of the patient. Additional examinations are conducted to determine the degree and form of pathology, as well as to identify the underlying disease:
- X-ray. Radiography of the skull reveals thinning of the bones of the skull and the divergence of the seams between them; on the inner surface of the cranial vault there is a symptom of “finger indentations”. Hydrocephalus, caused by stenosis of the brain’s plumbing, is accompanied by a decrease in the volume of the posterior cranial fossa on X-rays of the skull. Hydrocephalus in Dandy-Walker syndrome, on the contrary, is characterized by an increase in the volume of the posterior cranial fossa on craniograms. Hydrocephalus at the closure of one of the interventricular messages is manifested by the asymmetry of the skull visible on the craniogram.
- Computer or MR tomography. Tomographic diagnostic methods make it possible to determine the nature of hydrocephalus, to identify the place of occlusion of the cerebrospinal tract or an existing congenital anomaly, to diagnose a causal disease (tumor, cyst, hematoma, etc.). With hydrocephalus, the use of MRI of the brain is most informative. If vascular disorders are suspected, MRA of cerebral vessels is indicated.
- Echography. Of the ultrasound diagnostic methods for hydrocephalus, echoencephalography is used to determine the degree of increase in intracranial pressure. In children of the first year of life, ultrasound scanning of the brain through an open fontanel using ultrasonography is possible.
- Consultation of an ophthalmologist. An ophthalmologist evaluates visual disturbances and the condition of the optic nerve discs. As a rule, the list of ophthalmological examinations for hydrocephalus includes ophthalmoscopy, determination of visual acuity and perimetry.
- Lumbar puncture. In the absence of contraindications to identify the causal disease, it is possible to perform a lumbar puncture with subsequent examination of the cerebrospinal fluid. Congenital hydrocephalus of infectious etiology requires PCR diagnostics to determine the type of infection that caused it.
The choice of treatment for hydrocephalus depends on its etiology. Conservative therapy is often carried out with acquired hydrocephalus caused by inflammatory diseases, TBI, ventricular hemorrhage. The main disease is being treated, and diuretics (acetazolamide, furosemide) are prescribed to reduce the degree of hydrocephalus and increased intracranial pressure.
Congenital hydrocephalus usually requires surgical intervention aimed at correcting the underlying malformation. If hydrocephalus is caused by the presence of a volumetric process in the brain, then it is also treated surgically. According to the indications, intracranial hematoma is removed, operations to remove tumors, autopsy or total excision of a brain abscess, separation of adhesions in arachnoiditis, etc.
In cases where it is not possible to eliminate the cause of this disease, bypass operations are used:
- cystoperitoneal bypass
- endoscopic ventriculocysternostomy of the bottom of the III ventricle
- ventriculoperitoneal bypass
- lumboperitoneal bypass
- external ventricular drainage
They are aimed at creating additional ways of outflow of cerebrospinal fluid from the cranial cavity. Shunting operations can be performed as an addition to the surgical treatment of the underlying disease, if during the operation it is not possible to restore normal circulation of the cerebrospinal fluid.