Hydrocephalus

Definition

Hydrocephalus refers to an increase in the volume of cerebrospinal fluid. This liquid circulates in the brain and plays a key role in the protection of the neurological sphere: it allows in particular to eliminate waste and absorb shocks that can damage brain structures. However, an excessive accumulation of cerebrospinal fluid is a problem. It can cause dilation of the cerebral ventricles and increased intracranial pressure. The consequences of hydrocephalus are numerous and can affect the body at different levels.

Types

It is possible to distinguish several types of hydrocephalus:

• obstructive hydrocephalus which is characterized by obstruction of cerebrospinal fluid flow;
• communicating or nonobstructive hydrocephalus which corresponds to a problem in resorption of cerebrospinal fluid;
• normal pressure hydrocephalus, which is a special case and which is still poorly understood to this day.

Causes

Hydrocephalus can be congenital or acquired, in other terms, it can be present from birth or be the consequence of certain other pathologies.

As their name suggests, obstructive hydrocephalus is caused by an obstruction in the brain. It can have several explanations:

• a brain tumor osbstructing the circulation of the cerebrospinal fluid;
• a malformation of the central nervous system such as Dandy-Walker malformation;
• a cerebral hemorrhage like hemorrhage in the ventricles of the brain;
• meningitis.

Communicating hydrocephalus is usually caused by inflammation of meninges, that can may be due to:

• an infection;
• cerebral hemorrhage.

Normal pressure hydrocephalus is a specific form of the disease whose origin is still poorly understood today. It appears with age from the sixties.

Symptoms

Obstructive and communicating hydrocephalus can have these symptoms:

• lethargy;
• vomitings;
• seizures;
• strabismus;
• visual disturbances;
• learning disabilities such as memory problems, attention problems, or difficulties in processing information;
• deterioration of executive functions;
• motor disorders;
• urinary incontinence;
• dementia.

Normal pressure hydrocephalus is characterized typically by a triad of clinical signs:

• gait and balance disorders;
• urinary disorders marked by urinary incontinence;
• cognitive disturbances characterized by dementia.

Diagnosis

Diagnosis of hydrocephalus is made by transcranial ultrasound in newborns and by brain CT scan or MRI for adults.

Treatment

The treatment of hydrocephalus depends on many parameters including the cause, the severity and the evolution of the disorder. The age of the hydrocephalus patient is also taken into account. Depending on the case, treatment may be based on:

• simple monitoring by imaging and measurement of the cranial circumference;
• lumbar punctures;
• a surgical intervention consisting of a ventricular shunt, as illustrated below.