Hydrocephalus occurs in both infants and adults. It is usually congenital, but can also develop later in life due to certain circumstances (e.g., infections, brain tumors).
Hydrocephalus results from an imbalance in the fluid levels within the head: The cavities in the brain (ventricles) fill with an excessive amount of cerebrospinal fluid, enlarge, and thereby displace the solid brain tissue. This leads to a sharp increase in pressure within the brain.
Infants react differently to the increase in pressure than adults, as their skulls are not yet fully formed. The bones of their skulls have not yet fused together. Due to the increased pressure in the brain, their skulls can expand, thereby partially compensating for the pressure.
In hydrocephalus, impaired cerebrospinal fluid circulation leads to increased intracranial pressure © pikovit | AdobeStock
Hydrocephalus can be detected as early as the prenatal (pre-birth) diagnostic phase: The enlarged ventricles are clearly visible in images of the unborn baby.
Hydrocephalus occurs in various forms—depending on how it developed in the patient.
Hereditary causes of hydrocephalus include, for example,
- a brain malformation,
- skull bone malformations, and
- impaired brain development.
Acquired forms of hydrocephalus are usually caused by
Obstructive hydrocephalus is the most common form of hydrocephalus, accounting for about 60 percent of cases. It is caused by
- brain tumors,
- brain malformations,
- brain inflammation, and
- blood clots.
Cerebrospinal fluid accumulates at a narrow point in the brain and cannot drain, causing intracranial pressure to rise. A typical narrow point is the aqueduct. It connects the third and fourth ventricles and is sometimes narrowed from birth or even completely closed. Nonresorptive hydrocephalus is less common (30 percent). In this case, usually as a result of meningitis, there is reduced resorption. This means that too little cerebrospinal fluid drains away.
Hypersecretory hydrocephalus (prevalence: approximately 10 percent) can result from carbon monoxide or mercury poisoning. Encephalitis is also considered a cause of this form of hydrocephalus. A severe congenital brain malformation (insufficient brain mass) leads to hydrocephalus e vacuo. Both the external and internal cerebrospinal fluid spaces are enlarged from birth. Consequently, they also fill with more cerebrospinal fluid.
The symptoms of hydrocephalus differ between infants and children on the one hand and adults on the other.
Symptoms of hydrocephalus in infants and toddlers
- Accelerated head growth (exceeding the percentile)
- unusually large head (macrocephaly)
- Bulging fontanelle (the space between the skull bones that has not yet closed)
- Prominent (congested) cranial veins
- an abnormal eye position in which a white strip of the sclera is visible above the cornea (sunset sign)
- Vomiting upon waking
- Balcony forehead (large head with a prominent forehead)
Symptoms of hydrocephalus in children, adolescents, and adults
- severe headaches
- Vomiting on an empty stomach
- Visual disturbances (double vision)
- Impaired consciousness, up to and including coma
- Gait disturbances
- Impaired memory function
- Reduced ability to concentrate
Additional symptoms of hydrocephalus in older adults
Hydrocephalus is diagnosed using imaging techniques such as
- ultrasound,
- magnetic resonance imaging (MRI), and
- computed tomography (CT).
The most appropriate method depends on the patient’s age and the circumstances of the examination.
In infants, ultrasound is usually the first method used. In infants, the bones of the skull have not yet fused together completely, which allows for satisfactory image quality with ultrasound.
In some cases, an additional measurement of intracranial pressure is performed in the clinic’s neurosurgery, neurology, or neuropediatrics departments.
Hydrocephalus is treated surgically in a hospital’s neurosurgery department. A proven method is the placement of a shunt. A tiny hole is drilled into the patient’s skull, and a very thin catheter with a silicone tube is inserted through it. From there, it runs under the patient’s skin and drains the excess cerebrospinal fluid into the abdominal cavity, for example. There, the body breaks it down (ventriculoperitoneal shunt/VP shunt). A valve located behind the ear adjusts to the current pressure level in the ventricle. This helps reduce the high pressure in the brain.
A VP shunt allows excess cerebrospinal fluid to be drained into the abdominal cavity via a catheter © rumruay | AdobeStock
The shunt is barely visible from the outside and is also used in infants. Infants and children who receive a shunt early on can—depending on the underlying condition—develop completely normally thereafter. However, their prognosis is even better if the physician is able to eliminate the cause of their hydrocephalus.
If the third ventricle is affected (e.g., aqueductal stenosis), an endoscopic ventriculostomy (ETV) can be performed. This involves drilling a tiny hole in the wall of the ventricle. Medication (symptomatic treatment) is used for hydrocephalus only on a short-term basis at most.
Regular follow-up examinations are important for all patients with hydrocephalus. This allows doctors to detect and treat new narrowings or dysfunction of the shunt system at an early stage.
What is hydrocephalus?
Hydrocephalus is a condition in which cerebrospinal fluid accumulates in the ventricles and fluid-filled spaces of the brain. Impaired cerebrospinal fluid circulation leads to increased pressure within the skull. Hydrocephalus can be congenital or acquired.
What symptoms does hydrocephalus cause?
Typical symptoms include headache, nausea, vomiting, gait disturbances, and problems with concentration and memory. In normal-pressure hydrocephalus, urinary incontinence and cognitive impairments frequently occur. In infants, an enlarged fontanelle or an increase in skull size may be signs of hydrocephalus.
What are the different types of hydrocephalus?
Types of hydrocephalus include obstructive hydrocephalus, malresorptive hydrocephalus, and communicating hydrocephalus. In communicating hydrocephalus, the absorption of cerebrospinal fluid is impaired, whereas in obstructive hydrocephalus, the outflow from the ventricles is blocked. A distinction is also made between hydrocephalus in adults and acquired hydrocephalus.
How is hydrocephalus diagnosed?
Diagnosis is usually made through an MRI or CT scan of the brain. Additionally, a lumbar puncture, neurological examinations, and an assessment of the internal and external cerebrospinal fluid spaces may be necessary. Doctors also evaluate cerebrospinal fluid production, intracranial pressure, and the size of the ventricles.
How is hydrocephalus treated?
Hydrocephalus is often treated surgically. Shunts or an external ventricular drain are implanted to divert cerebrospinal fluid into the abdominal cavity or the right atrium of the heart. Alternatively, endoscopic procedures such as ventriculocisternostomy are used in neurosurgery.
