Hydrocephalus

The term "hydrocephalus" defines the abnormal accumulation of cerebrospinal fluid (CSF) within the normal brain cavities (ventricles of the brain). Hippocrates first mentioned the term "hydrocephalus" in neonates and infants presenting swelling of the head. Normally CSF is produced within the ventricles and then fed either to the base of the skull and spinal canal or to the top of the brain from where it is then drained  to the venous system. The main function of CSF is to protect the brain and spinal cord from contact with the rough inner surface of the skull and spine, both in the movements of our body, and in slight accidents.

Moreover, the CSF regulates the transport of important nutrients to the nervous system, while removing metabolic products from the nervous tissue. The normal brain produces a daily pint of CSF (20 ml / hour), while the fluid pressure ranges from 0-18 cm H2O, depending on the posture and activity of the individual.

Hydrocephalus is a condition in which cerebrospinal fluid (CSF) remains usually under pressure in the ventricles of the brain. The reason is that there is an imbalance between production and absorption of CSF. Hydrocephalus should not be confused with other situations in which the ventricles of the brain  swell due to lack of / deterioration of brain tissue (atrophy) .


Essentially the following mechanisms that can lead to hydrocephalus:

• Obstruction of CSF circulation
• Difficulties in venous outflow and
• Increased production of CSF
• Malabsorption of  CSF

The causes of hydrocephalus are numerous and quite confusing: infectious conditions (encephalitis), brain mass lesions, trauma, degenerative diseases, abuse and a series of unknown factors are considered responsible for its development.

For years now treatment is based on a threefold structure.

• early diagnosis
• Pharmaceuticals and
• surgery

Clinical picture and treatment

The symptoms of hydrocephalus are more evident in very young children. The head circumference grows rapidly with a change in shape of head  especially a prominent forehead  and dilation of the veins of the scalp. Older children display focal symptoms such as headache and vomiting, personality change, oculomotor palsy, spasticity, etc.

Diagnosis is made by combining clinical picture, ultrasound (for newborns) and radiological examinations (X-ray skull, CT and MRI).
Treatment is designed primarily to remove any possible cause of obstruction (tumor, dysplasia) and the most common surgery is the drainage of CSF to balance production with the absorption and removal of CSF.

Hydrocephalus in adults usually associated with space-occupying lesions (tumors, hemorrhages, ischemia, congenital anomalies) and after craniocerebral injuries.

Moreover, Hydrocephalus of low or normal pressure, namely Normal pressure hydrocephalus is found in the elderly, a special form which is considered to be due to increased intracranial pressure and elasticity of brain tissue resulting in permanent swelling of the ventricles. A proportion of patients improved after the insertion of a  ventriculoperitoneal  CSF drainage valve.

The symptoms of adults in more acute situations include, signs of increased intracranial pressure with vomiting, agitation, headache, fatigue, swelling of the optic disc etc. In ‘normal pressure hydrocephalus’ symptoms of dementia, gait and memory disturbances, and urinary incontinence are observed.

The diagnosis is made with a combination of laboratory and imaging tests and treatment is primarily aimed ,as with  children, at removing the possible cause.

In most cases, a regulated a  ventriculoperitoneal  CSF drainage is inserted, while in a limited  percentage of cases an alternative endoscopic procedure called third ventriculostomy can be performed.


There are the following three types of hydrocephalus:

• Primary or idiopathic (unknown cause)
• Secondary,as a result of
• bleeding (subarachnoid or intracerebral)
• injury
• tumor or cyst
• intracranial surgery
• meningitis
• stenosis or blockage of CSK drainage duct
• overproduction of CSF (choroid plexus papilloma)
• Congenital (abnormal mafromations in fetal or neonatal-infantile period)

Also, subject to when it develops  hydrocephalus is classified as acute or chronic.


IDIOPATHIC HYDROCEPHALUS

Idiopathic Hydrocephalus usually occurs in the elderly. In several cases it also occurs in patients with years of alcohol or drug abuse because of the brain atrophy related to  taking such substances. In the process of brain aging in some individuals the normal pathways of CSF drainage to the venous circulation (sagittal upper vagina) block with as result the accumulation of fluid within the ventricles, "chronic" compression of the brain.

In situations such as craniocerebral injuries, hemorrhagic stroke (subarachnoid or intraventricular hemorrhage), tumors or infections (meningitis) normal drainage is disrupted resulting in the accumulation of CSF, increased intracranial pressure and compression of the brain (hydrocephalus secondary). When the compression is acute or subacute (ie it evolves in hours, days or weeks) the victim has persistent headache, vomiting, reduction of vision (oculomotor palsy), unstable posture, gait, confusion, sleepiness, drowsiness or coma . In contrast, chronic accumulation of excess fluid is absorbed by the brain itself but with some stress in neuronal function and perfusion.


SYMPTOMS:

• memory loss ("amnesia"), particularly in recent
• difficulty in walking (small, slow steps or instability with frequent falls or a complete lack of posture and gait-instability )
• frequent urination, urgent urination or incontinence.

This situation is sometimes confused with senile dementia, premature aging or cerebral atrophy, a common form of which is Alzheimer disease. Hydrocephalus of the elderly initially displays mobility disabilities, often confused with Parkinson's disease.


DIAGNOSIS

CT scan, which shows the dilatation of the ventricles is used to diagnose idiopathic hydrocephalus, which usually occurs after the age of 65.

Today we have other diagnostic tests (magnetic resonance imaging, puncture and measurement of pressure in the brain, measurement of the CSF drainage and temporary, neuropsychological testing, gait analysis videoscope)to use where the CT is not conclusive and does not help the diagnosis.


Treatment
When you definitively diagnose hydrocephalus in the elderly (the medical term is "Idiopathic normal pressure or" Hydrocephalus), then CSF bypass surgery is proposed.A system of narrow silicone tubes are placed under the skin which have an intermediary valve that regulates drainage of fluid. The one end of the tube is placed in the ventricles of the brain and the other to the free peritoneal cavity of the abdomen. The peritoneal cavity has the capacity to absorb CSF. When the proper patient selection criteria is followed, surgery is highly effective and improvement of memory, gait and continence particularly remarkable for the patient and immediately recognizable by their relatives.


History of  Hydrocephalus valves

The first attempts of CFS  bypass surgery were performed in the early 20th century with rubber tubing or artificial opening pathways
within the brain cavity (ventricular system) using an endoscope.

Today the pressure valves we use have their pressure programmed by special ultrasound machine and do not require surgical replacement.