Hydrocephalus is a condition of abnormal buildup of fluids within the brain resulting in a wide range of clinical features and constitutes a significant burden to the affected individual.

How do doctors identify it? 

What are the treatment options available? 

This topic will discuss the diagnosis and management strategies of hydrocephalus in order to regain normal brain fluid circulation and relief symptoms. 

Understanding hydrocephalus 

Definition 

Hydrocephalus is a Greek word literally meaning “water head”.¹​​ In normal situations the body continuously produces a fluid that surrounds the brain and the spinal cord from the outside and also travels through ducts and spaces (ventricles) of the brain from inside. This fluid is called cerebrospinal fluid (CSF) which is important for: 

• protecting the brain in case of trauma by absorbing shock force and acting as a cushion
• delivering nutrients to the nervous tissues 
• removing brain wastes² ​

In hydrocephalus, the CSF starts to accumulate and raise the pressure within the brain and distend its accommodating spaces causing the brain to swell and be compressed against the skull bones, or it results in head expansion in infants and small children because their skull is open and not yet formed properly. It results from one of the three following mechanisms: 

• overproduction of CSF exceeding the ability of absorption 
• reduced absorption 
• blockage of CSF drainage system² ​

Types of hydrocephalus 

The main types of hydrocephalus are: 

Obstructive (noncommunicating) hydrocephalus

It results from CSF flow obstruction at any level of its pathway which can be caused by a birth defect leading to narrowing of the ducts or due to the compression effect of some benign and malignant tumours of the brain.

Communicating hydrocephalus 

This is caused due to a problem with CSF absorption in the intact drainage system and happens in certain conditions like: 

• Subarachnoid haemorrhage which describes the bleeding into the space around the brain
• Inflammatory conditions of the brain (encephalitis) or its coverings (meningitis)
• Head trauma 

Hypersecretory hydrocephalus

It is due to the overproduction of CSF which is caused most of the time by a tumour (which can be benign or cancerous) of the cells responsible for production of the CSF.^3,4 ​

Another classification: 

Hydrocephalus can also be classified into two main categories: 

• Congenital hydrocephalus: presents at birth or can be detected during pregnancy 
• Acquired hydrocephalus: happens at any age³ ​

Diagnosing hydrocephalus 

Any delay in detecting hydrocephalus can result in fatal consequences like permanent brain damage, mental and physical disabilities, coma and death therefore, prompt recognition is essential for achieving the best outcomes and avoiding complications.³ ​

Diagnosing any condition requires a combination of several methods, which are: 

Clinical features 

The doctor starts with investigating the medical history of the patient addressing the physical signs and symptoms and then performs a thorough clinical examination to check for any features of hydrocephalus specific for each age group or causative agent. 

In newborns and infants 

Hydrocephalus manifests differently in newborns as a result of their immature skull structure; they have softer bones with gaps between them to allow space for brain growth unlike an adult's skull which is a single enclosed space with no gaps. They can present with: 

• Head enlargement: the already spaced bones separate from each other as a result of fluid accumulation and the infant's head will appear larger than usual
• Bulging fontanelles: fontanelles are the soft spots found between the bones of the skull and tend to swell with any rise in pressure
• Soft and shiny scalp with the multiple visible veins 
• Eye pupil turns downward and child fails to look upward 
• Stiff posture 
• Rise of intracranial pressure: if the pressure within the skull reached a certain limit, symptoms would develop, such as vomiting, irritability, poor feeding and failure to gain weight¹ ​

In other age groups 

Symptoms include: 

• Neck pain 
• Headache 
• Vomiting 
• Disturbed vision 
• Irritability 
• Seizures 
• Coma³ ​

Imaging techniques 

Imaging is the most useful modality for confirming the diagnosis of hydrocephalus. The most frequently utilised techniques are: 

Ultrasound 

Ultrasound scan through the anterior fontanelle is remarkably useful for evaluating CSF spaces and ducts and in spotting early fluid collection in under 18 months of age as long as the fontanelle is still open, it can be performed as a bedside investigation. Hydrocephalus can also be detected by ultrasound on pregnancy follow-up visits, this allows early intervention and treatment.¹ ​

Computed tomographic (CT) scan 

CT scan is best efficient in emergency situations as it is rapid and more accessible. It is able to visualise the ventricles as well as brain structure. However, CT possesses a significant risk of radiation and as children with hydrocephalus require multiple scans throughout their life radiation constitutes a major limitation for its use.⁵ ​

Magnetic resonance imaging (MRI) 

The preferable choice for diagnosing hydrocephalus is MRI which provides more accurate, detailed and high-quality images. A drawback is that it requires more time than CT scan (about 30-60 minutes) during which the patient needs to remain still and it is generally less accessible.⁵ ​

Measurement of intracranial pressure (ICP) 

Intracranial pressure is the pressure of the contents of the skull which is usually elevated in hydrocephalus. Doctors sometimes ask for ICP measurements to diagnose hydrocephalus or to guide treatment plans. It's an invasive procedure that involves the insertion of a sensor device into the fluid spaces to monitor the pressure.⁵ ​

Lumbar puncture: 

The doctor may sometimes ask for a lumbar puncture procedure in which a needle is inserted into the back to take a sample of the CSF around the spinal cord. Analysis of the sample may reveal infection or bleeding.³ ​

Treatment options 

Medical management

Historically, when surgical interventions were rare, pharmacological treatment was prevalent, however, recently their role has become less significant as they didn't demonstrate plausible outcomes. Scientists have been trying to develop new non-surgical measures to avoid the complications of surgery. They act by reducing CSF volume, reducing inflammation or protecting nerve fibres but they showed limited success. These drugs include: 

• Diuretics: like acetazolamide and furosemide 
• Steroids: like betamethasone 
• Thrombolytic drugs in cases of bleeding⁶ ​

Surgical treatments

Surgery remains the cornerstone management modality for hydrocephalus. It was first introduced in 1955 and proved to be very efficient and simple, surgeries have dramatically altered the course of the disease.

Ventriculoperitoneal (VP) shunt 

VP surgery is widely known and performed at all ages and it is done under general anaesthesia and involves the introduction of a soft tube through a burr hole in the skull. It has an end at one of the CSF ventricles within the brain while the other end is inserted into the abdomen (or tummy) of the patient, with a valve connected to it. The tube stays in the body and drains the extra CSF from the brain into the abdominal cavity with the valve regulating fluid flow.

Complications of VP shunt are: 

• Shunt infection 
• Shunt blockage 
• Shunt disconnection 
• Over-drainage⁵ ​

Endoscopic third ventriculostomy (ETV) 

ETV is a newer and less invasive procedure done under the guidance of a camera. The surgeon will create a single opening in the skull through which a probe is inserted into the third ventricle and create small holes to allow CSF to spill out of the ventricle and be absorbed by the surrounding tissues. No device is left in the head. It is used most of the time in obstructive hydrocephalus.¹ ​

Fontanelle ventricular tap and external ventricular drain 

Those procedures are done as a temporary method in the emergency settings when a shunt cannot be urgently placed.

Fontanelle tap is done in infants with open fontanelle in which the doctor inserts a needle into the fontanelle to access the ventricles to remove CSF. While in external ventricular drain a device is placed to drain CSF out of the body.³ ​

The multidisciplinary approach 

The multidisciplinary team approach is essential for the proper management and follow-up of hydrocephalus especially in the children population because they require more closeup monitoring throughout their childhood and adolescence and to be successfully transfused to adult care. The different specialities involve: 

• Paediatric neurology 
• Neurosurgery 
• Ophthalmology 
• Rehabilitation³ ​

Summary 

Hydrocephalus is an abnormal accumulation of cerebrospinal fluid in the brain that is diagnosed with a combination of history, clinical evaluation and imaging and is mainly treated with surgical interventions such as ventriculoperitoneal shunt or endoscopic third ventriculostomy under the guidance of a multidisciplinary team to achieve the best outcomes.