Hydrocephalus

What is hydrocephalus?

Hydrocephalus is a condition in which too much cerebrospinal fluid (CSF) — the clear fluid that surrounds and cushions the brain and spinal cord — builds up inside the skull. The fluid collects in spaces within the brain called ventricles, which are natural chambers where CSF is produced and stored. When the fluid cannot drain or be absorbed properly, the ventricles enlarge and press on surrounding brain tissue. Because the skull is rigid, this pressure can affect how the brain works.

The name comes from Greek words meaning “water” and “head,” and hydrocephalus is sometimes described in older or informal language as “water on the brain.” The fluid involved is not actually water, however, but cerebrospinal fluid, which the body normally makes, circulates, and reabsorbs in a continuous cycle every day.

Hydrocephalus can affect people of any age. It occurs in newborns and infants, where it may be present at birth (congenital hydrocephalus) or develop soon after; in older children and adults, often after an injury, infection, bleeding, or tumor (acquired hydrocephalus); and in older adults, in a distinct form called normal pressure hydrocephalus, where fluid builds up gradually without a dramatic rise in pressure. Understanding what is hydrocephalus in a given patient depends heavily on age, cause, and how quickly the fluid accumulates.

Doctors also distinguish between two broad mechanical types. In obstructive (non-communicating) hydrocephalus, a physical blockage stops CSF from flowing between the ventricles or out of them. In communicating hydrocephalus, the fluid can flow but is not absorbed properly into the bloodstream. This distinction matters because it influences which hydrocephalus treatment a neurosurgeon may recommend.

Symptoms of hydrocephalus

Hydrocephalus symptoms vary widely depending on the person’s age, the cause, and how quickly pressure builds inside the skull. Rapidly developing hydrocephalus tends to cause dramatic, urgent symptoms, while slowly developing forms may cause subtle changes that are easy to mistake for other conditions, especially in older adults.

Symptoms in infants and babies

Because a baby’s skull bones have not yet fused, the head can enlarge to accommodate extra fluid. Common signs in infants include:

• An unusually large head or a head that grows faster than expected at checkups
• A bulging or tense fontanelle — the soft spot on top of a baby’s head
• Prominent scalp veins and a thin, shiny appearance of the scalp
• Downward-looking eyes (sometimes called “sunsetting” eyes)
• Irritability, poor feeding, or vomiting
• Sleepiness or reduced alertness
• Seizures in some cases

Symptoms in older children and adults

Once the skull bones have fused, the head cannot expand, so rising pressure produces different symptoms:

• Headache, often worse in the morning or when lying down
• Nausea and vomiting
• Blurred or double vision
• Problems with balance and coordination
• Drowsiness, difficulty staying awake, or confusion
• Difficulty concentrating or a decline in school or work performance
• Urinary urgency or incontinence in some cases

Symptoms of normal pressure hydrocephalus in older adults

Normal pressure hydrocephalus (NPH) typically affects people over 60 and develops slowly. It is classically described by a combination of three problems, although not every patient has all three:

• Difficulty walking — often a slow, shuffling, or “magnetic” gait, as if the feet are stuck to the floor
• Cognitive changes — slowed thinking, forgetfulness, and reduced attention, which can resemble dementia
• Loss of bladder control — urgency progressing to incontinence

Because these symptoms overlap with Parkinson’s disease, Alzheimer’s disease, and normal aging, NPH is often recognized late. This matters because, unlike many causes of cognitive decline, NPH can often improve with treatment, so careful evaluation is important when these symptoms appear together.

Causes and risk factors

Hydrocephalus develops when the balance between how much cerebrospinal fluid is produced and how much is drained or absorbed is disturbed. Hydrocephalus causes fall into three broad mechanisms: a blockage in the fluid pathways, poor absorption of fluid into the bloodstream, or — rarely — overproduction of fluid.

Congenital causes (present at or before birth)

• Aqueductal stenosis — narrowing of the small channel (the cerebral aqueduct) that connects two of the brain’s ventricles; this is one of the most common congenital causes
• Neural tube defects such as spina bifida, in which the spinal column does not close completely during development
• Brain malformations that disturb normal fluid pathways
• Infections during pregnancy, such as rubella or toxoplasmosis, which can affect fetal brain development
• Bleeding in the brain of premature infants, a recognized complication of very early birth

Acquired causes (developing later in life)

• Bleeding in or around the brain (hemorrhage), for example after a ruptured blood vessel or stroke
• Head injury, which can cause bleeding or scarring that blocks fluid pathways
• Infections such as meningitis (inflammation of the membranes covering the brain), which can scar the tissues that absorb CSF
• Brain tumors or cysts that press on or block fluid pathways
• Complications of brain surgery in some cases

For normal pressure hydrocephalus in older adults, a clear cause often cannot be identified, although it can follow bleeding, infection, or injury. Risk factors for hydrocephalus in general include premature birth, a history of central nervous system infection or bleeding, previous brain surgery, and certain conditions during pregnancy. Hydrocephalus is not contagious, and in most cases it is not inherited, although a small number of genetic forms exist.

Diagnosis

Hydrocephalus diagnosis begins with a careful medical history and a neurological examination, in which the doctor assesses alertness, eye movements, muscle strength, coordination, reflexes, and — in adults — walking pattern and memory. In infants, the doctor measures head circumference and compares it with growth charts, and examines the fontanelle.

Imaging of the brain is essential to confirm the diagnosis. The main tests include:

• Ultrasound — often the first test in infants, because sound waves can pass through the open fontanelle to show the ventricles. It is also used before birth during routine pregnancy scans, where enlarged ventricles may first be noticed.
• Magnetic resonance imaging (MRI) — a detailed scan using magnetic fields, considered the most informative test in most cases. MRI shows the size of the ventricles, can often reveal the cause of the blockage, and helps plan treatment.
• Computed tomography (CT) — a rapid X-ray–based scan, frequently used in emergencies because it quickly shows enlarged ventricles or bleeding.

Enlarged ventricles on a scan do not by themselves prove hydrocephalus, because ventricles can also enlarge when brain tissue shrinks with age or disease. Doctors therefore interpret imaging together with the patient’s symptoms and examination findings.

When normal pressure hydrocephalus is suspected in an older adult, additional tests are often used to predict whether treatment is likely to help. The most common is a lumbar puncture (spinal tap), in which a doctor removes a sample of cerebrospinal fluid from the lower back with a thin needle. If walking, thinking, or bladder control improves temporarily after fluid is removed, this suggests the person may benefit from surgery. In some centers, an extended lumbar drainage test over one to several days, or measurement of CSF pressure, may also be performed. Neuropsychological testing — structured assessment of memory and thinking — can help distinguish NPH from other causes of cognitive decline. At Acibadem, this evaluation is typically coordinated by the neurology and neurosurgery departments working together.

Treatment options

There is currently no medication that cures hydrocephalus, and the condition does not usually resolve on its own once established. Effective hydrocephalus treatment is almost always surgical, aimed at restoring the balance of cerebrospinal fluid by diverting it away from the brain or reopening its natural pathways. The choice of procedure depends on the type of hydrocephalus, its cause, and the patient’s age and overall health.

Shunt surgery

The most common treatment is placement of a shunt — a thin, flexible tube implanted under the skin that drains excess fluid from the ventricles to another part of the body, most often the abdominal cavity (a ventriculoperitoneal or VP shunt), where the fluid is safely absorbed. The shunt includes a valve that controls how much fluid drains; many modern valves are adjustable from outside the body using a magnetic device, so drainage can be fine-tuned without further surgery.

Shunts are effective in many cases, but they are not maintenance-free. They can become blocked, infected, or drain too much or too little fluid, and they may need to be revised or replaced over a person’s lifetime — particularly in children, who may outgrow parts of the system. Anyone with a shunt, and their family, is usually taught to recognize the signs of shunt malfunction, such as returning headaches, vomiting, drowsiness, or fever, so problems can be treated promptly.

Endoscopic third ventriculostomy (ETV)

For some patients — especially those with obstructive hydrocephalus, such as aqueductal stenosis — a procedure called endoscopic third ventriculostomy may be an alternative to a shunt. Using a small camera (endoscope) passed into the ventricles through a small opening in the skull, the surgeon creates a tiny opening in the floor of the third ventricle. This allows fluid to bypass the blockage and flow along a new internal route, where it can be absorbed naturally. When successful, ETV avoids the need for a permanent implanted device, though it is not suitable for every type of hydrocephalus and the opening can occasionally close over time. In selected infants, ETV is sometimes combined with a procedure that reduces fluid production (choroid plexus cauterization).

Treating the underlying cause

When hydrocephalus is caused by a tumor, cyst, or other removable blockage, treating that underlying problem — for example, surgically removing a tumor — may restore normal fluid flow, sometimes without the need for a permanent shunt.

Temporary measures and watchful waiting

In certain situations, such as bleeding in premature infants or acute hydrocephalus after hemorrhage, doctors may place a temporary external drain to relieve pressure while the underlying problem stabilizes. Medications that reduce fluid production are occasionally used as a short-term bridge, but they are not a long-term solution. In a small number of patients with very mild, stable, and slowly progressing findings, doctors may recommend careful monitoring with repeated scans and examinations rather than immediate surgery; this decision is individualized and made by a specialist team. Hydrocephalus surgery is generally performed by neurosurgeons; at Acibadem it is managed within the neurosurgery department, including pediatric neurosurgery for children.

Living with hydrocephalus and outlook

The outlook for people with hydrocephalus varies considerably and depends on the cause, the age at which it develops, how quickly it is recognized, and how well treatment controls the fluid buildup. Many people who are treated promptly go on to lead full, active lives — attending school, working, and participating in sports with sensible precautions. Others, particularly those whose hydrocephalus was caused by significant bleeding, infection, or malformation, may have lasting effects such as learning difficulties, problems with attention or coordination, vision changes, or epilepsy.

Living with a shunt usually means attending regular follow-up appointments and staying alert to signs of malfunction throughout life. Children treated for hydrocephalus often benefit from developmental monitoring and, when needed, supportive services such as physical therapy, occupational therapy, or educational support. Adults with normal pressure hydrocephalus often experience meaningful improvement in walking after shunt surgery; improvements in thinking and bladder control are also possible, though they are less predictable, and doctors cannot guarantee any specific outcome in an individual patient.

It is honest to say that hydrocephalus is generally a lifelong condition that is managed rather than cured. With modern treatment and ongoing follow-up, however, the pressure on the brain can usually be controlled, and many complications can be prevented or treated when they are caught early.

Frequently asked questions

What is hydrocephalus in simple terms?

Hydrocephalus means there is too much cerebrospinal fluid — the fluid that normally cushions the brain — inside the skull. The fluid collects in chambers within the brain called ventricles, causing them to enlarge and press on brain tissue. It can happen at any age and has many possible causes, from birth conditions to injuries, infections, bleeding, and tumors.

Can hydrocephalus heal on its own?

In most cases, no. Once cerebrospinal fluid begins to accumulate because of a blockage or absorption problem, the imbalance usually persists and often worsens without treatment. Rare, borderline cases may remain stable and be monitored, but this decision should only be made by a specialist. Most people with confirmed hydrocephalus will need a surgical procedure to control the fluid buildup.

How serious is hydrocephalus?

Untreated hydrocephalus can be serious and, in acute cases, life-threatening, because rising pressure can damage the brain. With timely diagnosis and treatment, however, the outlook is often much better: many treated patients live full lives. The seriousness in any individual case depends on the cause, how quickly the fluid builds up, and how promptly it is treated.

What are the first symptoms of hydrocephalus in adults?

Early hydrocephalus symptoms in adults often include headaches that may be worse in the morning, nausea, blurred or double vision, balance problems, unusual drowsiness, and difficulty concentrating. In older adults with normal pressure hydrocephalus, the first sign is frequently a slow, shuffling walk, sometimes followed by memory problems and bladder urgency. Because these symptoms have many possible causes, a medical evaluation is needed to identify the reason.

What does hydrocephalus treatment involve?

Hydrocephalus treatment is usually surgical. The most common option is a shunt — a thin implanted tube that drains excess fluid, most often to the abdomen, where the body absorbs it. Some patients with a blockage-type hydrocephalus can instead have an endoscopic third ventriculostomy, in which the surgeon creates a small internal opening so fluid can bypass the blockage. When a tumor or cyst is the cause, removing it may resolve the problem. Your doctor will recommend the approach best suited to the specific type of hydrocephalus.

How long is recovery after shunt surgery?

Recovery varies from person to person. Many patients spend a few days in the hospital after shunt placement and gradually return to normal activities over the following weeks, following their surgical team’s guidance. Symptom improvement may be rapid in some cases and more gradual in others, particularly in normal pressure hydrocephalus. Lifelong follow-up is generally recommended, because shunts can require adjustment or revision over time.

Can a child with hydrocephalus develop normally?

Many children treated early for hydrocephalus develop well and attend mainstream school, though some experience learning, attention, motor, or vision difficulties and benefit from additional support. Development depends on the underlying cause, any associated brain conditions, and how promptly treatment was provided. Regular developmental checkups help identify and address any needs early, and doctors cannot predict an individual child’s outcome with certainty.

When to see a doctor

Anyone with known or suspected hydrocephalus — and anyone caring for someone with a shunt — should seek medical care promptly if warning signs appear. Rapidly increasing pressure inside the skull is a medical emergency.

Seek urgent medical attention if you or your child has:

• A severe or rapidly worsening headache, especially with vomiting
• Unusual drowsiness, difficulty waking, or confusion
• New vision problems such as blurred or double vision
• Seizures
• In an infant: a bulging soft spot, rapid head growth, downward-looking eyes, repeated vomiting, high-pitched crying, or poor feeding
• In someone with a shunt: return of previous symptoms, fever without an obvious cause, or redness, swelling, or tenderness along the shunt tubing
• Sudden problems with balance, walking, or bladder control

For less urgent concerns — such as gradually worsening walking, memory changes, or bladder problems in an older adult, or a child’s head growing faster than expected — an appointment with a doctor should still be arranged without delay. Early hydrocephalus diagnosis and treatment give the best chance of protecting brain function and improving quality of life.