Hydrocephalus: Symptoms, Causes & Treatment

What Is Hydrocephalus?

Hydrocephalus is a condition where excess cerebrospinal fluid (CSF) accumulates in the brain's ventricles (fluid-filled cavities), creating pressure that can damage brain tissue. The condition can occur at any age and has multiple causes, from congenital abnormalities to infections and injuries. Treatment typically involves surgical placement of a drainage system called a shunt.

The brain and spinal cord are surrounded by cerebrospinal fluid (CSF), a clear, colorless liquid that serves several critical functions. CSF acts as a cushion to protect the brain from injury, delivers nutrients to brain tissue, and carries away waste products. The body continuously produces new CSF—approximately 500 milliliters daily—while simultaneously absorbing older fluid to maintain a precise balance.

Hydrocephalus develops when this delicate balance is disrupted. The problem can arise because the body produces too much CSF, the fluid cannot circulate properly through the brain's ventricles and channels, or the body cannot absorb the fluid adequately. When CSF accumulates faster than it can be absorbed, pressure builds within the skull, potentially causing damage to delicate brain tissue.

The term "hydrocephalus" comes from the Greek words "hydro" (water) and "cephalus" (head), which is why the condition was historically called "water on the brain." However, the excess fluid is specifically cerebrospinal fluid, not water. The condition was also formerly referred to as "water head" in some languages and cultures.

Types of Hydrocephalus

Medical professionals classify hydrocephalus into several types based on its underlying mechanism and timing of onset. Understanding these distinctions is important because treatment approaches may vary depending on the specific type diagnosed.

Communicating hydrocephalus occurs when CSF can flow between the ventricles but absorption into the bloodstream is impaired. The ventricles remain connected, but the fluid cannot be removed efficiently. This type commonly results from infections, hemorrhage, or inflammation that damages the absorption sites.

Non-communicating (obstructive) hydrocephalus develops when CSF flow is blocked somewhere within the ventricular system. A tumor, cyst, or structural abnormality may obstruct the narrow passages connecting the ventricles. Because fluid continues to be produced but cannot drain properly, pressure builds rapidly in the blocked areas.

Normal pressure hydrocephalus (NPH) is a unique form that primarily affects adults over 60 years of age. Despite the enlarged ventricles visible on brain imaging, the CSF pressure measurements may appear normal or only slightly elevated. This seemingly paradoxical finding is why the condition is called "normal pressure" hydrocephalus. NPH accounts for approximately 5% of all dementia cases and is particularly important to identify because it may be reversible with treatment.

Hydrocephalus ex vacuo occurs when brain tissue shrinks due to stroke, traumatic injury, or degenerative disease. The ventricles enlarge to fill the space left by the lost tissue, but this is not true hydrocephalus because there is no actual increase in CSF pressure.

What Causes Hydrocephalus?

Hydrocephalus can be caused by brain hemorrhage, meningitis (brain membrane infection), head trauma, brain tumors blocking fluid flow, or congenital abnormalities present at birth. In older adults with normal pressure hydrocephalus (NPH), the cause is often unknown. Children with spina bifida may also develop hydrocephalus.

The causes of hydrocephalus vary significantly depending on when the condition develops and the patient's age. In some cases, multiple factors may contribute to the development of the condition. Understanding the underlying cause helps physicians determine the most appropriate treatment approach and predict potential outcomes.

Congenital Causes

Some children are born with hydrocephalus due to developmental problems that occurred during pregnancy. The brain's ventricular system may not have formed properly, creating blockages or abnormal connections that prevent normal CSF flow. Genetic factors can play a role in some cases, though hydrocephalus is not typically inherited in a straightforward pattern.

Spina bifida, a birth defect where the spine does not close completely, is frequently associated with hydrocephalus. The structural abnormalities affecting the spine can also impact CSF circulation in the brain. Children with myelomeningocele, the most severe form of spina bifida, have a particularly high risk of developing hydrocephalus.

Hydrocephalus can sometimes be detected before birth through routine prenatal ultrasound examinations. When discovered during pregnancy, specialists can plan appropriate care and interventions for immediately after delivery.

Acquired Causes

Hydrocephalus that develops after birth—whether in infancy, childhood, or adulthood—is called acquired hydrocephalus. Several conditions can trigger its development:

• Brain hemorrhage: Bleeding in or around the brain, including strokes and traumatic injuries, can block CSF absorption or circulation. Premature infants are particularly vulnerable to intraventricular hemorrhage.
• Meningitis: Bacterial or viral infections of the brain membranes can cause inflammation and scarring that impairs CSF flow and absorption.
• Brain tumors: Growths in the brain can physically obstruct the pathways through which CSF flows, causing rapid buildup of pressure.
• Head trauma: Severe head injuries can damage the brain's CSF circulation system, leading to hydrocephalus weeks or even months after the initial injury.
• Subarachnoid hemorrhage: Bleeding in the space between the brain and its surrounding membranes can interfere with CSF absorption.

Normal Pressure Hydrocephalus

NPH presents a particular diagnostic challenge because in most cases, no specific cause can be identified. This idiopathic form of NPH accounts for approximately half of all cases in older adults. The remaining cases may be traced to previous brain hemorrhage, head trauma, infection, or surgery—though sometimes these events occurred years or even decades before symptoms appeared.

Researchers continue to investigate why NPH develops and why it predominantly affects people over 60 years of age. Current theories suggest that age-related changes in brain structure and CSF dynamics may make older adults more susceptible to this condition.

What Are the Symptoms of Hydrocephalus?

Hydrocephalus symptoms vary by age. Adults may experience difficulty walking, cognitive impairment, urinary incontinence, severe headaches, nausea, and vision problems. Infants may have an enlarged head, bulging fontanelle, and developmental delays. The classic triad of normal pressure hydrocephalus includes gait disturbance, dementia, and urinary problems.

The symptoms of hydrocephalus depend on several factors, including the patient's age, the type of hydrocephalus, how quickly the condition develops, and individual variations in brain response to increased pressure. Recognizing these symptoms early is crucial because prompt treatment can prevent permanent brain damage and significantly improve outcomes.

Symptoms in Adults Over 60 (Normal Pressure Hydrocephalus)

Normal pressure hydrocephalus typically presents with a characteristic triad of symptoms that often develop gradually over months or years. The symptoms may initially be subtle and easily attributed to "normal aging," which unfortunately leads to delayed diagnosis in many cases.

Gait disturbance is usually the first and most prominent symptom. Patients describe difficulty walking, poor balance, and a feeling of unsteadiness. The walking pattern often appears shuffling or magnetic—as if the feet are stuck to the floor. Falls become more frequent, and patients may need to use walls or furniture for support.

Cognitive impairment affects memory, thinking speed, and concentration. Unlike Alzheimer's disease, where memory loss is typically the primary problem, NPH cognitive symptoms tend to involve slowed thinking, difficulty with attention, and problems with executive functions like planning and organizing. Patients may seem apathetic or disengaged from their surroundings.

Urinary symptoms begin with increased urgency—a sudden, strong need to urinate that is difficult to postpone. As the condition progresses, patients may experience urinary incontinence. These symptoms often develop after the gait and cognitive problems have already appeared.

Symptoms in Adults, Young Adults, and Older Children

When hydrocephalus develops in adults or older children due to causes other than NPH, the symptoms may appear more rapidly and dramatically. The presentation depends largely on how quickly pressure builds within the skull.

• Severe headaches: Often worse in the morning or when lying down, and may not respond well to typical pain medications
• Nausea and vomiting: Particularly common with rapidly increasing pressure
• Vision problems: Double vision, blurred vision, or downward deviation of the eyes
• Balance and coordination difficulties: Problems with walking and fine motor control
• Cognitive changes: Difficulty concentrating, memory problems, personality changes
• Drowsiness and fatigue: Excessive sleepiness that may progress to decreased consciousness
• Bladder problems: Urinary urgency or incontinence

Symptoms in Infants and Young Children

In infants under two years of age, the skull bones have not yet fused together, allowing the head to expand in response to increased pressure. The most visible sign of hydrocephalus in babies is often an abnormally enlarged head or a head that is growing faster than expected.

The fontanelle—the soft spot on top of a baby's head where the skull bones have not yet joined—may appear tense, bulging, or pulsating. Normally soft and slightly curved inward when the baby is upright, a bulging fontanelle can indicate increased pressure inside the skull.

Other symptoms in infants may include:

• Downward deviation of the eyes (sunset sign)
• Irritability or unusual fussiness
• Poor feeding
• Vomiting
• Excessive sleepiness
• Developmental delays
• Seizures

When Should You See a Doctor?

Contact a healthcare provider if you notice gradually worsening walking difficulties, memory problems, or urinary urgency—especially if you're over 60. Seek emergency care immediately for sudden severe headache, especially if you've never had such headaches before. In infants, rapid head growth or a bulging fontanelle requires urgent medical evaluation.

Knowing when to seek medical attention for hydrocephalus can be challenging because many symptoms develop gradually and may be attributed to other causes. However, timely diagnosis significantly impacts treatment outcomes, so it's important to recognize warning signs and act appropriately.

Non-Urgent but Important Symptoms

Schedule an appointment with your primary care physician or a neurologist if you experience:

• Progressive difficulty with walking or balance over weeks to months
• Gradual worsening of memory, concentration, or thinking abilities
• Increased urinary urgency or new incontinence issues
• Persistent headaches that differ from your usual pattern
• Unexplained changes in personality or behavior

These symptoms warrant medical evaluation but typically do not require emergency care. Your doctor can perform initial assessments and arrange appropriate imaging studies and specialist referrals.

Emergency Symptoms

Seek immediate emergency medical care for:

• Sudden, severe headache—especially if it's a "worst headache of your life" or completely different from previous headaches
• Headache accompanied by neck stiffness, fever, or sensitivity to light
• Sudden vision changes, including double vision or loss of vision
• Loss of consciousness or difficulty staying awake
• Sudden confusion or disorientation
• Seizures
• In infants: bulging fontanelle, seizures, persistent vomiting, or extreme irritability

How Is Hydrocephalus Diagnosed?

Hydrocephalus is diagnosed through neurological examination, brain imaging (CT scan or MRI) showing enlarged ventricles, and lumbar puncture to measure cerebrospinal fluid pressure. Special tests like tap tests or lumbar infusion tests help predict whether shunt surgery will be beneficial. Diagnosis can take time because symptoms overlap with other conditions.

Diagnosing hydrocephalus requires a careful combination of clinical evaluation, imaging studies, and sometimes specialized tests. The diagnostic process aims not only to confirm the presence of hydrocephalus but also to identify its type, underlying cause, and likelihood of responding to treatment.

Physical and Neurological Examination

The evaluation begins with a thorough medical history and physical examination. Your doctor will ask about symptom onset, progression, and any relevant medical history including previous head injuries, infections, or neurological conditions.

A neurological examination assesses walking and balance (particularly important for NPH), cognitive function through memory and thinking tests, eye movements and vision, reflexes and muscle strength, and coordination. You may be asked to complete questionnaires evaluating your symptoms and daily functioning.

Brain Imaging

Imaging studies are essential for diagnosing hydrocephalus and typically include:

Computed Tomography (CT scan) provides rapid imaging of the brain and is often the first test performed. CT scans clearly show enlarged ventricles and can identify many causes of hydrocephalus, such as tumors or hemorrhage. The test is quick, widely available, and useful for emergency evaluation.

Magnetic Resonance Imaging (MRI) offers more detailed images of brain structures without radiation exposure. MRI can reveal subtle abnormalities that CT might miss and provides better visualization of CSF flow patterns. Specialized MRI sequences can actually show the movement of cerebrospinal fluid through the brain.

Cerebrospinal Fluid Studies

A lumbar puncture (spinal tap) may be performed to measure CSF pressure and analyze the fluid composition. During this procedure, a needle is inserted into the lower back to access the spinal fluid. The test can help distinguish between different types of hydrocephalus and rule out infections.

For suspected NPH, additional specialized tests may include:

Tap test (large volume lumbar puncture): A larger-than-usual amount of CSF is removed to see if symptoms temporarily improve. Improvement suggests that a permanent shunt may be beneficial.

Lumbar infusion test: Fluid is slowly infused into the spinal canal while pressure is measured, assessing the brain's ability to absorb CSF.

Extended lumbar drainage: A temporary catheter drains CSF over several days while symptoms are monitored for improvement.

Prenatal and Infant Diagnosis

Hydrocephalus can be detected before birth through routine prenatal ultrasound examinations. If enlarged ventricles are seen, additional monitoring and specialist consultations help plan delivery and postnatal care.

In infants, regular measurement of head circumference is part of standard well-child visits and can detect abnormally rapid head growth. If hydrocephalus is suspected, ultrasound through the fontanelle can visualize the ventricles without exposing the baby to radiation.

How Is Hydrocephalus Treated?

The primary treatment for hydrocephalus is surgical placement of a shunt—a thin tube that drains excess cerebrospinal fluid from the brain to another body cavity, usually the abdomen. Endoscopic third ventriculostomy (ETV) is an alternative for some patients. Over 50% of NPH patients experience significant improvement after shunt surgery, particularly in walking ability.

While hydrocephalus cannot be cured, it can be effectively managed with treatment that diverts excess cerebrospinal fluid away from the brain. The goal is to reduce pressure, relieve symptoms, and prevent further brain damage. The specific treatment approach depends on the type and cause of hydrocephalus, patient age, and overall health.

Shunt Surgery

The most common treatment for hydrocephalus is the surgical implantation of a shunt system. A shunt is a flexible tube that redirects CSF from the brain's ventricles to another part of the body where it can be absorbed into the bloodstream.

The ventriculoperitoneal (VP) shunt is the most frequently used type. One end of the tubing is placed in a brain ventricle, and the other end is threaded under the skin to the abdominal cavity (peritoneum), where the CSF is absorbed. The shunt includes a valve that regulates flow and prevents too much or too little drainage.

The surgery typically takes about one hour and is performed under general anesthesia. The surgeon makes small incisions in the scalp, neck, and abdomen to position the tubing. Modern shunts may include programmable valves that can be adjusted externally using magnets, allowing fine-tuning without additional surgery.

After surgery, most patients can get up and move around the same day or the day after. Hospital stays typically range from one to a few days for adults. Children who have been operated may need to stay up to a week for monitoring.

Endoscopic Third Ventriculostomy (ETV)

For some patients with obstructive hydrocephalus, an alternative procedure called endoscopic third ventriculostomy may be appropriate. During ETV, a neurosurgeon uses a tiny camera and instruments to create a small hole in the floor of the third ventricle, allowing CSF to flow directly to the brain surface where it can be absorbed.

ETV avoids the need for a permanent shunt and its associated long-term complications. However, it is not suitable for all types of hydrocephalus and may not be appropriate for very young infants. The procedure is most successful for obstructive hydrocephalus caused by a blockage between the ventricles.

Treatment for Infants

When hydrocephalus is detected before birth and the baby's head has grown significantly, delivery by cesarean section may be recommended to reduce the risk of birth complications.

After birth, the infant is carefully monitored to determine whether treatment is needed. In some cases, the body can compensate for CSF imbalances, and the hydrocephalus resolves without intervention. However, many infants will require shunt placement to manage the condition.

Children with shunts need regular follow-up throughout childhood and into adulthood. As children grow, shunts may need to be revised or replaced.

What Are the Possible Complications?

Shunt complications are relatively common and include shunt blockage (causing symptoms to return), infection requiring treatment or shunt replacement, and overdrainage leading to headaches or, rarely, bleeding around the brain. Children may need shunt revisions as they grow. Regular follow-up is essential for monitoring shunt function.

While shunt surgery is generally safe and effective, complications can occur. Understanding potential problems helps patients and families recognize warning signs and seek appropriate care promptly.

Shunt Malfunction

The most common shunt complication is malfunction, typically due to blockage of the tubing. The blockage may occur at either end of the shunt or within the valve mechanism. When a shunt stops working properly, CSF again accumulates in the brain, and original symptoms return.

Signs of shunt malfunction may include return of headaches, nausea, or vomiting; worsening of gait, cognitive, or urinary symptoms (in NPH); drowsiness or changes in consciousness; irritability in children; and vision problems. If you experience these symptoms, contact your neurosurgical team promptly. Shunt malfunction can usually be corrected surgically.

Infection

Shunt infections occur when bacteria colonize the shunt system. Symptoms may include fever, redness or tenderness along the shunt tract, headache, and nausea. Shunt infections are serious and typically require removal of the infected shunt, antibiotic treatment, and eventually placement of a new shunt.

Overdrainage

Sometimes shunts drain CSF too quickly, causing headaches that are typically worse when upright and improve when lying down. In rare cases, overdrainage can cause bleeding around the brain (subdural hematoma) due to brain tissue pulling away from the skull as pressure decreases.

Modern programmable shunts help reduce overdrainage by allowing valve settings to be adjusted. If overdrainage persists, surgical revision may be necessary.

Long-term Considerations

Most people with shunts require lifelong monitoring and may need multiple shunt revisions over their lifetime. Children typically need more frequent revisions as they grow. Before discharge from the hospital, you will receive detailed instructions about warning signs and who to contact if problems arise.

What Is It Like Living with Hydrocephalus?

Living with hydrocephalus varies greatly depending on the underlying cause and whether other conditions are present. Many people live normal lives with properly functioning shunts, while others may need assistive devices or rehabilitation services. Some patients may develop epilepsy. Support from healthcare teams and patient organizations can help manage daily challenges.

The impact of hydrocephalus on daily life varies tremendously from person to person. For some, a properly functioning shunt eliminates symptoms entirely, allowing a completely normal life. For others, particularly those with additional neurological conditions, ongoing challenges may require various support services.

After Successful Treatment

Many adults treated for NPH experience significant improvement in symptoms, particularly walking ability. Cognitive function and urinary control may also improve, though recovery in these areas can be more gradual. Regular follow-up appointments ensure the shunt continues functioning properly.

For children born with hydrocephalus, outcomes depend on many factors, including the underlying cause, whether there are associated conditions, and how quickly treatment was initiated. Many children with hydrocephalus develop normally and attend regular schools, while others may need additional educational support or therapy services.

Potential Ongoing Challenges

Some individuals with hydrocephalus experience lasting effects that may include learning difficulties or cognitive challenges, motor coordination problems, vision issues, and increased risk of epilepsy. These challenges can often be addressed with appropriate therapies, educational accommodations, and medical management.

People with complex needs may benefit from coordinating with rehabilitation services that provide comprehensive support for managing daily activities and maximizing independence.

Support for Families

Caring for someone with hydrocephalus can be demanding, and family members often need support too. Learning about shunt warning signs, managing medical appointments, and addressing emotional challenges are all part of the caregiver experience.

Patient organizations and support groups can provide valuable resources, including educational materials, peer support, and advocacy services. Connecting with others who understand the hydrocephalus journey can be tremendously helpful.

How Does Cerebrospinal Fluid Work?

Cerebrospinal fluid (CSF) is a clear liquid that surrounds and protects the brain and spinal cord. It cushions the brain from injury, delivers nutrients, and removes waste products. The body produces about 500 ml of CSF daily. Hydrocephalus occurs when CSF production, circulation, or absorption is disrupted, causing fluid accumulation and increased brain pressure.

Understanding how cerebrospinal fluid normally functions helps explain why hydrocephalus develops and how treatment works to restore balance.

Normal CSF Circulation

Cerebrospinal fluid is produced primarily by specialized tissue called the choroid plexus, located within the brain's ventricles. The ventricles are four interconnected cavities: two lateral ventricles (one in each hemisphere), the third ventricle, and the fourth ventricle.

From its production sites, CSF flows through the ventricular system, exiting into the space surrounding the brain and spinal cord (the subarachnoid space). The fluid circulates around the brain and down the spinal canal before being absorbed back into the bloodstream through specialized structures called arachnoid granulations.

This continuous circulation—production, flow, and absorption—maintains a precise pressure and volume of CSF. When any part of this system fails, hydrocephalus can result.

What Goes Wrong in Hydrocephalus

Hydrocephalus develops through one of three mechanisms:

• Overproduction: Rarely, tumors of the choroid plexus can produce excessive CSF
• Obstruction: Blockages anywhere in the ventricular system prevent normal CSF flow
• Impaired absorption: Damage to the absorption sites prevents CSF from returning to the bloodstream

The accumulating fluid expands the ventricles, compressing surrounding brain tissue against the skull. This pressure can damage or destroy brain cells if left untreated, leading to the various symptoms of hydrocephalus.