Hydrocephalus

There is not just one form of hydrocephalus, but several, differentiated by the mechanism of cerebrospinal fluid (CSF) accumulation and the dynamics of its circulation in the brain. These distinctions are fundamental to making an accurate diagnosis and defining an appropriate treatment strategy.

Obstructive (or non-communicating) hydrocephalus

This form results from a physical blockage in the ventricular system, preventing CSF from circulating normally. This may be due to stenosis of the Sylvian aqueduct, a congenital malformation, or a tumor obstructing a passage. This is the most common type in children.

Communicating hydrocephalus

Unlike obstructive hydrocephalus, in this case the CSF flows freely through the ventricles, but its absorption by the arachnoid villi is impaired. This form occurs in particular after meningitis, hemorrhage, or head trauma.

Normal pressure hydrocephalus (NPH)

Particularly common in older adults, this form is characterized by ventricular dilation without any apparent increase in intracranial pressure. It is accompanied by cognitive impairment, balance problems, and incontinence.

Ex vacuo hydrocephalus

This variant is secondary to a loss of brain matter, often after a stroke or traumatic injury. It is not true hydrocephalus because there is no elevated intracranial pressure, but rather a passive expansion of the ventricles to compensate for brain atrophy.

The symptoms of hydrocephalus vary depending on the age of the person affected. The progression can be gradual or sudden, and the signs often reflect increasing intracranial pressure.

In infants

In babies, the cranial sutures are still open, allowing the skull to expand and sometimes masking the symptoms of intracranial pressure. However, certain signs are indicative: a rapid increase in head circumference, a bulging fontanelle, unusual irritability, or feeding difficulties.

In older children

As the child grows, the signs become more neurological: morning headaches, vomiting, blurred vision, balance difficulties, or walking problems. Behavioral changes or developmental delays may also occur.

In young and middle-aged adults

In this population, symptoms are sometimes mistakenly attributed to other disorders: chronic headaches, fatigue, difficulty concentrating, coordination problems, or incontinence.

In the elderly

Normal pressure hydrocephalus is an insidious form of the disease: it develops slowly, with a typical presentation combining walking difficulties, urinary incontinence, and cognitive decline. This clinical trio often remains underdiagnosed.

Hydrocephalus can be congenital or acquired. Its causes are multiple, reflecting the diversity of mechanisms that disrupt the circulation or absorption of cerebrospinal fluid. These causes may vary depending on the patient's age, medical context, or neurological history.

Congenital hydrocephalus

Present at birth or diagnosed in the first months of life, congenital hydrocephalus may be linked to malformations of the central nervous system. Myelomeningocele, a severe form of spina bifida, is often associated with hydrocephalus. It can also result from stenosis (particularly of the aqueduct of Sylvius), intrauterine infections, or genetic disorders.

Acquired hydrocephalus

This form can occur at any age following an event affecting the brain. In premature infants, intraventricular hemorrhages are common. In older children and adults, causes include brain tumors, infections (meningitis, abscesses), head trauma, and postoperative complications.

Certain factors increase the likelihood of developing hydrocephalus, particularly in newborns and infants. These factors are perinatal, genetic, or socio-environmental in origin.

• In newborns: Premature babies, especially those born before 30 weeks of gestation or weighing less than 1,500 grams, are at significant risk of intraventricular hemorrhage, a common precursor to hydrocephalus.
• Family and genetic factors: A family history of congenital hydrocephalus significantly increases the risk, particularly in monozygotic twins or siblings.
• Other factors: Male gender, maternal diabetes, and low socioeconomic status are also among the variables associated with increased risk.

The diagnosis of hydrocephalus is based on the evaluation of clinical neurological and radiological signs. The assessment is very often carried out in conjunction with neurologists. It involves cognitive tests, exercises, and gait assessment. In certain types of communicating hydrocephalus, such as “normal pressure hydrocephalus,” specialists perform a lumbar puncture test to better assess the diagnosis.

Some highly symptomatic cases of hydrocephalus are also discovered in acute situations, particularly in emergency departments. In infants, regular measurement of head circumference remains an essential screening tool. An abnormal increase in head size, a tense fontanelle, or changes in behavior may be warning signs.

The treatment of hydrocephalus is mainly based on techniques for diverting cerebrospinal fluid through neurosurgery. These procedures aim to restore the balance between CSF production and absorption in order to relieve the pressure exerted on the brain structures.

Ventriculoperitoneal shunt (VPS)

The most commonly used method involves inserting a catheter into the cerebral ventricle, connected to a regulating valve, then to a tube that drains the fluid into the peritoneal cavity. This is the most common and traditional solution, with good clinical results. The adjustable valve allows for fine adjustment of the flow rate of the cerebrospinal fluid.

Endoscopic ventriculocisternostomy (EVC)

This technique, which is less invasive in the long term, involves creating an opening in the floor of the third ventricle to allow CSF to flow directly into the subarachnoid spaces. It has the advantage of reducing the risk of chronic infections associated with ventriculoperitoneal shunting, but the indication for this procedure depends on the type of hydrocephalus and the patient's specific anatomical parameters.

Temporary and conservative treatments

In some unstable or premature patients, temporary measures may be considered, such as external ventricular drainage (EVD) or, in exceptional cases, the use of diuretics. These approaches are temporary, pending definitive treatment.

Even when treated, hydrocephalus can progress in unpredictable ways. Some forms stabilize, while others require repeated adjustments.
The most common complications occur with the shunt devices: obstruction, infection, catheter displacement. Continuous medical attention is therefore essential. In some cases, several surgical procedures are necessary over the course of a lifetime. Follow-up is therefore often recommended.

Medical advice should be sought immediately if symptoms suggestive of abnormal intracranial pressure are present. In infants, rapid growth of the head circumference, repeated vomiting, unusual irritability, or a bulging fontanelle should alert parents or caregivers. In older children, morning headaches, vision problems, balance difficulties, or behavioral changes should raise suspicion of hydrocephalus. In adults, especially those over the age of 60, the gradual onset of walking difficulties, memory problems, or unexplained incontinence warrants a thorough neurological examination.

At Hôpital de La Tour, the treatment of patients with hydrocephalus is part of a coordinated approach that combines medical expertise, cutting-edge technology, and human support. The facility has a full range of technical equipment for brain imaging (MRI, CT scan, transfontanellar ultrasound), facilitating rapid and reliable diagnosis.
Close collaboration between neurologists and neurosurgeons allows for a personalized response to each situation.

Why do infants develop large heads?

Because the sutures of the skull are not yet fused. This allows the skull to adapt to the increase in intracranial volume without immediately increasing pressure.

What are the most alarming signs in a child?

Repeated vomiting, unusual irritability, loss of appetite, a fixed downward gaze (sunset sign), or behavioral changes should prompt a visit to the doctor.

Does hydrocephalus cause mental retardation?

Not necessarily. It all depends on the cause, how early it is diagnosed, and the quality of care. Appropriate treatment can preserve cognitive functions.

Can hydrocephalus be detected during pregnancy?

Yes, prenatal ultrasound scans can sometimes reveal ventricular dilation, prompting a specialist evaluation and close monitoring.