What is hydrocephalus?
First thing to know: inside the skull is a liquid whose main role is to protect the brain by absorbing the shocks undergone at the level of the head. The cerebrospinal fluid (also called cerebrospinal fluid) also participates in the nutrition of the tissues of the central nervous system.
An adult has about 120-150 mL of cerebrospinal fluid (CSF) in their skull; a newborn has about 40-60 mL. This clear liquid (mainly composed of water, protein and glucose) circulates around the brain, in the ventricular system (a set of cavities located in the brain) but also in the subarachnoid space (which is located at the surface of the two cerebral hemispheres).
To know. In a healthy person, the brain “produces” every day about ½ liter of cerebrospinal fluid and re-absorbs the same amount so that the pressure remains constant inside the skull: this is a complex balance.
What is hydrocephalus? The word “hydrocephalus” comes from the ancient Greek “hudôr” (water) and “képhalê” (head). Hydrocephalus is therefore defined as an excess of cerebrospinal fluid inside the brain, in the ventricles.
This accumulation of cerebrospinal fluid can be linked to a circulation problem, when there is an obstacle in its path (we speak ofnon-communicating hydrocephalus or obstructive) or to a problem of reabsorption, that is to say of its evacuation (we then speak ofcommunicating hydrocephalus or non-obstructive).
Hydrocephalus: causes and symptoms
To know. Hydrocephalus is (fortunately) a rare pathology since it affects between 0.4 and 0.8 children in 1000 in the world.
Hydrocephalus is indeed a pathology that is observed more in children: often congenital (that is to say: present from birth), it can result from a malformation of the brain and / or its cavities during pregnancy – arachnoid cyst, Dandy-Walker syndrome, congenital toxoplasmosis … However, hydrocephalus can appear at any age, in particular due to:
- A brain tumor (ependymoma, meningioma, etc.) or a tumor of the spinal cord,
- Arachnoiditis: this is a specific meningitis which, although it can be infectious, can also occur after spinal surgery or (more rarely) after a lumbar puncture,
- Cerebral thrombophlebitis: it corresponds to the obstruction of a vein around the brain by a clot,
- A head trauma,
- A cerebrovascular accident (stroke).
What are the symptoms of hydrocephalus? In the newborn (who has a still flexible skull), the main symptom of hydrocephalus is macrocrania: the head appears abnormally large, the fontanel (that is to say: the membranous space which is the junction between the bones of the skull) is swollen, the skin of the skull appears thin and shiny, the veins of the scalp are visible …
This may be associated with vomiting, lack of appetite and energy, irritability, constantly looking down and / or seizures.
In children and adults (with a rigid skull and welded skull bones), hydrocephalus causes intracranial hypertension which can manifest through:
- Nausea and vomiting,
- Visual disturbances,
- Poor coordination,
- A lack of concentration,
- A delay in acquisition and a loss of autonomy (in children).
Attention ! Acute hydrocephalus often results in migraines (headaches) and abnormal fatigue: in the absence of care, they can quickly progress to coma and death.
To know. In the elderly, three symptoms may suggest hydrocephalus: walking and balance disorders, sphincter disorders (anal and / or urinary incontinence, pressing needs, etc.) and attention disorders ( memory, attention, communication problems …). It is often a normal pressure hydrocephalus (HPN).
Hydrocephalus: diagnosis and treatment
Diagnostic. In addition to the clinical examination, the diagnosis of hydrocephalus is confirmed by medical imaging examinations (CT scan or MRI) to highlight the accumulation of cerebrospinal fluid in the brain. In newborns or during pregnancy, prenatal or cranial ultrasound will be used instead.
Treatments. Besides the treatment of the cause (brain tumor, meningitis …) the management of hydrocephalus is based mainly on two techniques, surgical operations performed under general anesthesia:
- The implantation of a bypass valve. This device consists of a catheter that enters the ventricles of the brain, a valve often installed behind the ear, and a second catheter that goes to the heart (cardiac bypass valve) or, more often, up to the abdomen (peritoneal bypass valve). The objective: to allow the cerebrospinal fluid to evacuate towards the stomach or the heart in order to equalize the pressure in the skull. Hospitalization lasts 3 to 5 days. The entire device is subcutaneous, non-intrusive and not visible.
- La ventriculocisternostomie. This operation (performed under cerebral endoscopy) consists of making an opening in the cerebral ventricle to allow the passage of cerebrospinal fluid. This technique is only used when hydrocephalus results from an obstacle in the path of fluid circulation.
To know. Hydrocephalus is considered a chronic disease. The patient with a bypass valve receives medical surveillance every month for the first 6 months after the operation, then medical examinations every year.
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