Cerebrospinal fluid outflow disorder, hydrocephalus, dropsy of the brain
In hydrocephalus, cerebrospinal fluid accumulates in the ventricles of the brain. A common reason for this is that the cerebrospinal fluid cannot drain away due to a blockage. The intracranial pressure increases and the cerebral ventricles expand.
The symptoms depend on the age at which the hydrocephalus occurs. In babies and small children, the head enlarges, while later it can become noticeable through headaches or visual disturbances. With the help of imaging techniques such as ultrasound or magnetic resonance imaging, hydrocephalus can be easily detected, often even before birth. We usually treat hydrocephalus as part of an operation. As a rule, we place a shunt through which the cerebrospinal fluid can drain.
Hydrocephalus is characterized by an increased accumulation of fluid (cerebrospinal fluid) in the brain. This increases the intracranial pressure and the ventricles of the brain expand. Hydrocephalus is also known colloquially as “hydrocephalus” or formerly as “dropsy”.
Hydrocephalus can have many different causes. What they all have in common, however, is that the circulation of cerebrospinal fluid in the brain is disturbed. Hydrocephalus can be congenital and babies are born with it. However, it can also be acquired over the course of a lifetime. Possible causes can be brain tumors, brain injuries or a stroke.
In addition, hydrocephalus can be acute and chronic. Acute is when the intracranial pressure rises very quickly. In chronic hydrocephalus, the intracranial pressure rises gradually over a long period of time.
There are various forms of hydrocephalus: in hydrocephalus occlusus, there is a bottleneck that causes a build-up of cerebrospinal fluid. In hydrocephalus nonresorptivus, not enough cerebrospinal fluid is reabsorbed or absorbed via the blood.
The symptoms of hydrocephalus can vary. In babies, the enlarged head is usually typical. The skull of babies and small children is still soft and can compensate for the increased intracranial pressure to a certain extent – the head circumference grows. Hydrocephalus often occurs in conjunction with spina bifida (“open back”). In many cases, doctors can diagnose the disease before birth.
In older children and adults, neurological symptoms such as headaches, visual disturbances, dizziness or balance problems can be signs of hydrocephalus. Doctors detect the accumulation of fluid and enlarged ventricles in the brain using imaging techniques such as ultrasound, computer tomography or magnetic resonance imaging.
Hydrocephalus is usually treated with the help of an operation. If possible, an attempt is made to eliminate the cause, such as a tumor. In addition, we usually place a shunt – a kind of “detour” through which the cerebrospinal fluid can flow out.
It is estimated that around 1 in 1,000 babies are born with hydrocephalus. In this case, the disease is congenital and can be traced back to an abnormal development in the womb. Hydrocephalus can also develop in the course of life, for example due to brain injuries, meningitis, tumors or a stroke. However, the frequency cannot be precisely quantified. In principle, hydrocephalus can occur at any age. There are also different forms of hydrocephalus, which vary in frequency.
Some figures:
The cerebrospinal fluid is normally circulated. The human body produces it again and again, it flows out of the brain regularly and is reabsorbed via the bloodstream. Normally there is a balance between new production, outflow and resorption of the cerebrospinal fluid.
In many cases, hydrocephalus develops when the fluid can no longer drain properly because there is a blockage. The cerebrospinal fluid then builds up, the ventricles enlarge and the intracranial pressure rises. In babies and small children, the skull is still soft and can compensate for the increasing pressure to a certain extent – the head circumference increases. This is not possible in older children and adults because the skull is ossified.
There are different forms of hydrocephalus, which in turn can have different causes. The most important at a glance.
In the case of hydrocephalus occlusus or occlusive hydrocephalus, the cerebrospinal fluid cannot drain away or can no longer drain away sufficiently because there is a constriction in the drainage pathways. This can be compared to a water hose that is pinched off by an object – the water backs up and the pressure in the hose increases. There are various reasons why a bottleneck can form. Examples are:
Hydrocephalus occlusus can already develop in the womb, for example due to maldevelopment of the brain and spinal cord (neural tube defects). The disease often occurs together with spina bifida (“open back”). However, it can also develop over the course of a lifetime. At around 60 percent, hydrocephalus occlusus is the most common form.
In malresorptive hydrocephalus there is no constriction, but the resorption of the cerebrospinal fluid is disturbed. It accumulates and the intracranial pressure rises. The membranes that normally reabsorb the cerebrospinal fluid can stick together, for example due to proteins or cells. The most common causes of hydrocephalus malresorptivus are:
Hydrocephalus malresorptivus accounts for about 30 percent of all cases.
In hypersecretory hydrocephalus, the body produces too much cerebrospinal fluid. The causes can be, for example
Hydrocephalus hypersecretorius is responsible for about ten percent of cases.
Hydrocephalus e vacuo can occur when nerve tissue dies and the brain volume decreases. The cerebrospinal fluid chambers are then enlarged compared to the surrounding tissue. The reasons can be different:
In normal pressure hydrocephalus (“senile intracranial pressure”), the outflow of cerebrospinal fluid is disturbed and the cerebral ventricles expand without the intracranial pressure being significantly increased. Normal pressure hydrocephalus affects adults and occurs more frequently with increasing age. Experts classify it as a dementia disorder. The causes are unknown, but ageing processes and circulatory disorders probably play a role. Nevertheless, younger people can also contract the disease.
The symptoms of hydrocephalus depend on the cause, but also on the age at which it develops. In newborns, babies and small children, the skull is still soft and can deform and compensate for the increased intracranial pressure to a certain extent. The circumference of the head increases if the cerebrospinal fluid cannot drain away – the skull therefore moves away in this way. Sometimes the circumference of the skull can be very large. Hydrocephalus can often be detected on ultrasound before birth.
The following symptoms may occur:
Visual disturbances: The eyeball is twisted downwards, the gaze can no longer be directed upwards and the pupil resembles a sun setting behind the eyelid. The reason for this symptom is increased intracranial pressure, which compresses certain cranial nerves that in turn control eye movements.
If the bone sutures of the skull have closed and the fontanelles have ossified, hydrocephalus also causes other symptoms because the skull can no longer “grow along”. The increased intracranial pressure impairs blood flow to the brain and can also damage brain tissue.
In older children and adults, the symptoms depend on how quickly the hydrocephalus develops. The intracranial pressure can increase suddenly, but also slowly and gradually.
The following signs indicate increased hydrocephalus:
Unlike most childhood forms of hydrocephalus, adults usually suffer from chronic forms that are not life-threatening and also cause much less severe symptoms. These include chronic occlusive hydrocephalus and normal pressure hydrocephalus. The diagnosis is usually made clinically, i.e. on the basis of the symptoms. These include, in particular, a gait disorder with a small-step and wide gait pattern in which the feet seem to stick to the ground and in which turning on one’s own axis is particularly difficult and requires numerous steps. Furthermore, incontinence often occurs, as well as a disturbance of the short-term memory.
Chronic occlusive forms of hydrocephalus have often existed since childhood and cause no symptoms for years, until headaches, dizziness, epilepsy, depression or completely different symptoms suddenly appear in adulthood – there are almost no symptoms that this clinical picture cannot cause. It is crucial that these chronic forms are well investigated and carefully differentiated by experts from different disciplines from other diseases that appear very similar, such as Parkinson’s or Alzheimer’s disease. Treatment is then carried out surgically and usually has a very good prognosis.
In many cases, hydrocephalus can be detected by ultrasound before birth. Defects in the neural tube, from which the brain and spinal cord later emerge, can be diagnosed from around the 20th week of pregnancy. This includes, for example, spina bifida (open back). The malformations can be detected even more precisely in magnetic resonance imaging (MRI = magnetic resonance imaging).
For babies, measuring the circumference of the head is a standard part of preventive check-ups at the pediatrician. A comparison with previous measurements shows whether the head has become disproportionately larger. It is also determined whether the head circumference is in proportion to the height and weight. If this is not the case and the fontanel is still open, an ultrasound scan will help.
In the case of older children and adults, we first ask about the patient’s medical history (anamnesis). The following questions, for example, are helpful:
Computed tomography (CT) and magnetic resonance imaging (MRI) provide further information as to whether hydrocephalus is present. Sometimes we also determine the intracranial pressure. A lumbar puncture is used to remove cerebrospinal fluid via a fine needle. If normal pressure hydrocephalus is suspected, we also assess the gait pattern in the laboratory.
You cannot really prevent hydrocephalus. In general, you should make sure you eat a healthy diet during pregnancy and avoid harmful substances such as alcohol, smoking, drugs and environmental toxins. During this time, do not take any medication that you do not absolutely need. So the chances are good that your unborn child will develop normally. You should also have regular check-ups during your pregnancy. Antenatal care is a good way of detecting hydrocephalus and other malformations in unborn babies at an early stage.
A stroke caused by a cerebral hemorrhage or a blood clot can be the cause of hydrocephalus. You can also prevent this to a certain extent by leading a healthy lifestyle: no smoking, plenty of exercise, moderate alcohol consumption and a healthy diet. Brain injuries (traumas) also play a role as a cause. There are also various protective measures here.
The general advice is to always seek medical advice promptly if you experience any symptoms, for example neurological symptoms such as difficulty standing or headaches. If hydrocephalus is recognized early and treated quickly, late effects can be avoided in many cases.
The course and prognosis of hydrocephalus depend on the cause and extent. Certain forms can become life-threatening, for example if a cerebral hemorrhage or meningitis causes the intracranial pressure to rise rapidly. The brain is then no longer supplied with sufficient blood and can no longer fulfill its functions. Action must be taken immediately.
However, if hydrocephalus is diagnosed in good time, it can usually be treated well – depending on the cause. For example, a shunt through which the cerebrospinal fluid drains away can enable a largely normal life. Life expectancy is also usually not limited.
The treatment of hydrocephalus depends on the cause. Doctors always try to eliminate the cause that led to hydrocephalus. This can be a tumor, a blood clot from a stroke, a brain injury, meningitis or abnormal development in the womb. In most cases, for example, the fluid balance in the brain returns to normal once the tumor has been operated on. Scars or malformations that lead to a build-up of cerebrospinal fluid can also be corrected by surgery.
There are often no treatable causes for the chronic forms of hydrocephalus in adulthood and the development of the disease is still a mystery to experts. Fortunately, there are excellent therapies available that allow a very good overall prognosis for these diseases.