Hydrocephalus in Adults: Causes, Symptoms, And Treatment Options

Overview

Hydrocephalus is a chronic, neurological condition characterised by excess cerebrospinal fluid (CSF) accumulating in the ventricles of the brain, resulting in its enlargement and increased pressure.¹ CSF surrounds the brain and spinal cord, regulating the central nervous system and protecting it from injury. It also supplies nutrients and removes metabolic waste products from the brain. Normally, the body reabsorbs the CSF. Any blockage that hinders the flow or absorption of CSF can cause an increase in CSF volume within the ventricles, potentially leading to hydrocephalus.²

Hydrocephalus normally develops among children and the elderly (aged 60 plus), however, it can occasionally affect adults. It can either be congenital or acquired. In adults, there are four main types: hypersecretory, obstructive, communicating, and normal-pressure hydrocephalus (NPH).³

What causes hydrocephalus in adults?

In adults, hydrocephalus can arise from a variety of causes depending on the type and is frequently secondary to other neurological disorders such as cerebral haemorrhage (brain bleed), tumour, head trauma, and infection.⁴

Hypersecretory hydrocephalus 

Hypersecretory hydrocephalus develops due to an excess of CSF, most commonly due to a choroid plexus papilloma. This is a rare type of non-cancerous tumour that grows on the choroid plexus, the tissue in the brain responsible for the production of the CSF, resulting in the overproduction of CSF or a blockage in CSF drainage. In rare cases, Hypersecretory hydrocephalus may also be caused by cancer.³

Obstructive hydrocephalus 

Obstructive hydrocephalus also referred to as non-communicating hydrocephalus, is caused by a blockage in CSF flow.  The most common sites of obstruction are in the parts of the brain involved in the flow of CSF (the foramen Monro, the aqueduct of Sylvius, the foramen magnum, and the fourth ventricle). Most cases involve large tumours being the cause of the obstruction at any point along the CSF pathways.³

Communicating hydrocephalus

When the cerebrospinal fluid (CSF) is not effectively absorbed after passing through the ventricles, it results in communicating hydrocephalus. Impaired CSF absorption may be caused by: post-haemorrhagic changes, subarachnoid haemorrhage (bleeding in the area surrounding the brain), and meningitis.³

Normal-pressure hydrocephalus (NPH)

NPH is a kind of communicating hydrocephalus that most commonly affects individuals over the age of 60. It is caused by a progressive blockage of the channels responsible for CSF drainage in the brain, with little or no increase in pressure. The most common causes of this include cranial surgery, haemorrhages, or head injuries.⁵

When there is neurological damage from an injury or stroke, the brain matter narrows, leading to hydrocephalus ex-vacuo. CSF volume expands to fill the excess space left by the shrunken brain. Although the ventricles have expanded in these cases, the pressure is typically normal.⁵

What are the signs and symptoms of hydrocephalus in adults?

The symptoms of hydrocephalus vary distinctively among individuals and between age groups. Adults may experience gait abnormalities or dementia, whereas vomiting due to intracranial pressure is more common in children. Sometimes symptoms are mistaken for depression or other mental health problems.⁶ The symptoms associated with adult-onset hydrocephalus can be differentiated into cognitive symptoms and physical symptoms.

Cognitive symptoms

Cognitive symptoms of hydrocephalus include:^6,7

• Short-term memory loss
•  Difficulties with concentration and focusing
•  Problems with decision-making
•  Changes in behaviour and personality

Physical symptoms

Physical symptoms of hydrocephalus include:^6,7

• Headaches
• Vision Problems (diplopia, blurred vision, difficulty focusing the eyes, nystagmus, or strabismus)
• Balance disturbances (unsteady gait, ataxia)
• Sudden falls
• Seizures
• Acquired apraxia - the ability to produce coherent speech
• Aphasia - difficulty with speech, reading, writing and listening
• Difficulty in coordination
• Lethargy 

Primary symptoms of NPH among older individuals are:³

• Bladder incontinence
• Dementia
• Gait abnormality 

If NPH is left untreated, the symptoms tend to worsen with time. Individuals who have severe NPH and are untreated may have seizures, which may progress over time. 

How is hydrocephalus in adults detected?

Adult hydrocephalus is mostly diagnosed by reviewing your medical history, doing a physical examination, and conducting a thorough neurological evaluation, which may include diagnostic tests. Early diagnosis is crucial to alleviate disease progression.

Neurological examination

The neurological examination involves tests for the following:⁷

• Reflexes and muscle strength
• Coordination and equilibrium
• Ocular movements, hearing, and vision
• Emotion and mental state 

Diagnostic techniques

The diagnostic techniques to detect adult-onset hydrocephalus include:⁷

• Computed tomography (CT): detects enlargement or obstruction in ventricles
• Magnetic resonance imaging (MRI): more information on the brain tissue surrounding the ventricles, an evaluation of the CSF flow, and an assessment of the ventricles' enlargement can be obtained compared to a CT scan
• Lumbar puncture: also known as a spinal tap, determines CSF pressure and fluid analysis by inserting a 50cc needle into the lower back to remove CSF fluid
• Intracranial pressure monitoring: a tiny pressure sensor is inserted into the brain or ventricles through the skull to asses pressure and identify cerebral oedema
  • The CSF fluid is drained out if the pressure is increased to ensure oxygenated blood supply to the brain
• Fundoscopic examination: a light is shone into the eye to examine the optic nerve for evidence of high intracranial pressure

How is adult-onset hydrocephalus treated?

Timely diagnosis and treatment are essential. Hydrocephalus gradually progresses and causes irreversible brain damage as well as death if neglected. Whilst hydrocephalus cannot be cured,  it can be effectively managed through symptomatic treatment. 

Surgical intervention is the primary treatment option for hydrocephalus, either by correcting the CSF obstruction or by diverting CSF flow. Hydrocephalus due to intracerebral haemorrhage or carcinoma can be resolved by surgical removal of the underlying cause.³

Ventriculoperitoneal (VP) shunt

Ventriculoperitoneal shunt (VP) involves a shunt that moves the CSF from ventricles to other body cavities, specifically the peritoneal cavity. One end of the VP shunt, the catheter, is inserted into the peritoneum (the lining of the abdominal cavity). However, shunt insertion carries a risk of malfunction or infection, leading to symptoms such as headache, vomiting, double vision or seizures.⁸

Endoscopic third ventriculostomy (ETV)

Endoscopic third ventriculostomy (ETV) is often used to treat individuals with obstructive hydrocephalus. Using a neuroendoscope, a tiny hole is created in the third ventricle's floor to create a fresh CSF flow. As a result, CSF avoids the blockage and absorbs normally. This procedure does not involve the insertion of implants, reducing the risk of infection.⁹

External ventricular drain

The insertion of an external ventricular drain is the procedure used to treat acute hydrocephalus, which requires immediate medical attention. A catheter is inserted into the ventricles to drain CSF, reducing the pressure in the brain. Posthemorrhagic and post-meningitic hydrocephalus can be treated by lumbar puncture.³

What is the prognosis of hydrocephalus in adults?

The outcome of hydrocephalus depends on the cause of it, the severity of the symptoms, and the promptness of diagnosis and treatment. While some patients experience substantial benefits after treatment, others do not. Dementia can be resolved in certain NPH cases with shunt implantation. According to reports, the shunting procedure has a success rate of up to 80% if the cause is known, whilst the success rate ranges from 25 to 74% if the cause is unknown.⁵ However, shunt failure is possible, so further surgery may be required.³

Summary

Hydrocephalus is a long-term neurological disorder marked by an excess of CSF accumulating inside the brain's ventricles, leading to expansion and increased pressure in the brain. The incidence of hydrocephalus is greater in children and the elderly, but it can occur at any age. Hydrocephalus may result from an obstruction that prevents CSF from flowing or being absorbed, increasing the volume of CSF inside the ventricles. In adults, it is more commonly caused by a secondary neurological illness such as a stroke, tumour, haemorrhage, or infection.  Symptoms include headaches, vomiting, blurred vision, irregular gait, or dementia. Diagnosis is based on a complete physical and neurological evaluation, which may involve diagnostic imaging or a lumbar puncture. Although there is no known cure for hydrocephalus, it can be effectively controlled with symptomatic care. Treatment involves a surgical procedure (VP Shunt and ETV), which can either remove the CSF blockage or reroute the CSF flow.