Hydrocephalus: Symptoms, Causes & Treatment — What You Need to Know
Updated: 2 days ago
Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: September 2026
What Is Hydrocephalus?
Hydrocephalus is the buildup of cerebrospinal fluid (CSF) in spaces called ventricles deep within the brain. This buildup makes the ventricles larger and puts pressure on the brain.
Your brain floats in a bath of CSF. This fluid also fills large open structures called ventricles that lie deep inside your brain, keeping it buoyant and cushioned.
Hydrocephalus develops when there is a problem with how the body makes or absorbs CSF. Too much fluid builds up because it is either made too quickly or not absorbed fast enough.
CSF plays four important roles in keeping the brain healthy.
Buoyancy: Helps the brain float so it doesn't press too hard on the base of the skull.
Cushioning: Protects the brain from sudden movements or injury.
Waste removal: Carries away waste made by brain cells.
Pressure control: Moves between the brain and spinal cord to control pressure inside the skull and adjust to changes in blood flow.
The 5 Types of Hydrocephalus
Hydrocephalus is not one single condition. There are five recognized types, each with a different cause.
Congenital hydrocephalus: Starts before birth — the brain doesn't develop as expected in the womb, or gene changes are involved.
Communicating hydrocephalus: Fluid flows freely through the ventricles, but the body doesn't absorb it properly or makes too much.
Noncommunicating (obstructive) hydrocephalus: A blockage stops fluid flow inside the brain, so fluid builds up behind the blockage, enlarging nearby ventricles and raising skull pressure.
Normal-pressure hydrocephalus (NPH): Ventricles enlarge but fluid pressure stays typical; most common in older adults, affecting walking, memory, and bladder control.
Hydrocephalus ex vacuo: After a stroke, head injury, or other condition, brain tissue is lost and the brain shrinks, letting fluid fill the empty space; pressure usually stays typical.
Symptoms by Age: How Hydrocephalus Looks Different at Every Stage
The symptoms of hydrocephalus vary significantly by age. What to watch for in an infant is very different from what shows up in an older adult.
Infants: Watch the Head First
In infants, hydrocephalus most often shows up as changes to the head itself, plus physical symptoms.
Head changes: Head larger than usual; rapid increase in head size; a bulge or tense soft spot on top of the head.
Physical symptoms: Nausea and vomiting; sleepiness or sluggishness (lethargy); irritability; poor eating; seizures.
Eye and muscle signs: Eyes fixed downward (called "sunsetting of the eyes"); issues with muscle tone and strength.
Toddlers and Older Children
Among toddlers and older children, symptoms split into physical signs and behavioral or cognitive changes.
Physical: Headache; blurred or double vision; unusual eye movements; enlargement of the head; sleepiness; nausea or vomiting; trouble with balance; poor coordination; poor appetite; loss of bladder control or frequent urination.
Behavioral and cognitive: Irritability; personality change; decline in school performance; delays or difficulty with skills already gained, such as walking or talking.
Young and Middle-Aged Adults
Common symptoms in young and middle-aged adults include headache, sluggishness, and loss of coordination or balance. Loss of bladder control or frequent urination, vision problems, and a decline in memory, concentration, and other thinking skills that may affect job performance are also common.
Older Adults: Normal-Pressure Hydrocephalus
Among adults 60 and older, the classic presentation is the triad of normal-pressure hydrocephalus (NPH): loss of bladder control or frequent urination, memory loss, and trouble walking — often described as shuffling or feeling like the feet are stuck. Poor coordination or balance and a progressive loss of reasoning skills round out the picture.
When to See a Doctor: The Infant Emergency You Should Never Wait Out
Seek emergency medical care immediately for infants and toddlers with any of these symptoms: a high-pitched cry, difficulty with sucking or feeding, vomiting that happens again and again with no clear cause, or seizures.
Infant or toddler with high-pitched cry, feeding trouble, repeated vomiting, or seizures: Emergency care now.
Any age group with other hydrocephalus symptoms (headache, vision changes, balance problems, bladder issues, cognitive decline): Prompt medical attention.
Older adult with shuffling walk, memory loss, and bladder problems: See a doctor — NPH is treatable and often mistaken for dementia or aging.
More than one condition can cause hydrocephalus symptoms, so a timely diagnosis matters. Don't assume a shuffling walk or slipping memory in an older adult is just "getting older" — NPH is one of the few potentially reversible causes of dementia-like symptoms.
Causes: Why Too Much Fluid Builds Up
Hydrocephalus happens for one of three reasons. Blocked flow is by far the most common.
Blocked flow (most common): A blockage slows or stops CSF flow between the ventricles or between the ventricles and the spaces around the brain.
Trouble absorbing fluid (less common): Usually happens after swelling or inflammation from an illness or injury.
Making too much fluid (rare): Usually caused by a tumor in the fluid-producing area, such as a choroid plexus tumor.
Risk Factors: Who Is More Likely to Develop Hydrocephalus?
In many cases the cause is never found, but hydrocephalus can result from medical conditions or from issues affecting brain development before birth.
Newborns (Congenital Hydrocephalus)
In newborns, hydrocephalus may be caused by development of the central nervous system in a way that blocks CSF flow, bleeding inside the brain (a possible complication of premature birth), or an infection in the uterus during pregnancy, such as rubella or syphilis, which can cause swelling in the brain tissues of an unborn baby.
At Any Age
Hydrocephalus can also develop later in life due to health issues or injuries.
Brain or spinal cord tumors: Tumors can block or disrupt CSF flow.
Brain or spinal cord infections: Meningitis or mumps.
Bleeding in the brain: Caused by a stroke or head injury.
Other brain injuries: Any injury affecting how CSF flows or is absorbed.
Complications: What Happens Without Treatment
Hydrocephalus usually worsens over time if it is left untreated. Lack of treatment can lead to serious consequences, including learning delays, physical or developmental disabilities, or even death.
The good news: if hydrocephalus is mild and treated early, many people have few or no long-term complications.
How Hydrocephalus Is Diagnosed
A diagnosis is usually based on your symptoms, a general physical exam, a neurological exam, and brain imaging tests.
The neurological exam depends on age. A healthcare professional checks muscle strength, movement, balance, and senses such as touch or vision.
Ultrasound (babies, first test): Simple and low risk; the device is placed on the soft spot (fontanelle); can also detect hydrocephalus before birth during a routine prenatal scan.
MRI (adults, test of choice; children with sedation if needed): Uses radio waves and a magnetic field for detailed images; shows enlarged ventricles and helps find the cause; painless but noisy and requires lying still; some hospitals offer faster MRI that avoids sedation.
CT scan (emergencies): Special X-ray technology for cross-sectional views; fast and painless with a small amount of radiation, but shows less detail than MRI.
Treatment: The Two Main Surgeries
There are two main surgical treatments for hydrocephalus.
1. Shunt — the most common treatment
A shunt is a flexible tube with a one-way valve. The valve helps drain extra fluid from the brain at the right speed and in the right direction. One end of the tube is placed in a ventricle inside the brain, and the rest of the tubing is threaded under the skin, usually down to the belly or sometimes to the chest, where the body absorbs the fluid.
Most people with hydrocephalus need their shunt for life. Regular checkups are important to make sure it is working well.
2. Endoscopic third ventriculostomy (EVT)
In this procedure, a surgeon uses a small camera to look inside the brain and makes a tiny hole at the bottom of one of the ventricles. The opening lets extra fluid flow out of the brain, relieving pressure.
Surgical Complications to Know
Both procedures can cause complications. Shunts can stop draining or poorly regulate drainage because of mechanical problems, a blockage, or infections. EVT complications include bleeding and infections.
Problems after surgery need quick medical care — sometimes another surgery or other treatment is required. Call your healthcare professional right away if you have a fever or any symptoms of hydrocephalus.
Supportive Therapies and Long-Term Care
Some people with hydrocephalus, particularly children, need supportive therapies depending on the long-term complications. A children's care team might include the following.
Pediatrician or physiatrist: Oversees the treatment plan and medical care.
Pediatric neurologist: Specializes in neurological conditions in children.
Occupational therapist: Therapy to develop everyday skills.
Developmental therapist: Helps the child develop age-appropriate behaviors, social skills, and interpersonal skills.
Mental health professional: Psychologist or psychiatrist.
Social worker: Helps the family get services and plan care transitions.
Children in school may need special education. Adults with serious complications might need occupational therapists, social workers, or specialists in dementia care.
One important exception: in adults with normal-pressure hydrocephalus that causes no symptoms, treatment may not be needed at all — monitoring only, since it may take many years for symptoms to develop.
Can Hydrocephalus Be Prevented?
Hydrocephalus can't always be prevented — in many cases the cause is unknown or happens before birth. But certain steps may lower the risk, especially for conditions that lead to hydrocephalus later in life.
During Pregnancy
Regular prenatal care is the most important step. Routine checkups help catch infections and other issues that may affect brain development, and they lower the risk of preterm birth, which is linked to bleeding in the brain and a higher chance of hydrocephalus. Avoiding infections such as rubella and syphilis — through vaccination and good hygiene — also reduces risk.
At Any Age
Vaccinate against meningitis: Reduces the risk of brain infections that can cause hydrocephalus.
Prevent head injuries: Use car seats, helmets, and seat belts.
Treat brain infections early: Quick treatment for meningitis or encephalitis prevents complications.
Manage health conditions: Controlling blood pressure and overall health reduces stroke and tumor risks.
Should you or your child be vaccinated against meningitis? Ask a healthcare professional. The CDC recommends meningitis vaccination for preteen children and boosters for teenagers, plus vaccination for younger children and adults who travel to countries where meningitis is common, have an immune condition called terminal complement pathway deficiency, have a damaged or removed spleen, live in college dormitories, or join the military.
Coping and Support
With the help of therapies and educational services, many people with hydrocephalus live with few limitations.
If you have a child with hydrocephalus, there are many resources for emotional and medical support. Children with developmental disabilities might be eligible for government-sponsored healthcare and other support services — check with your state or county social services agency. Hospitals and organizations serving people with disabilities offer emotional and practical support, and your healthcare team can help connect you with other families living with hydrocephalus.
Adults living with hydrocephalus may find valuable information from organizations dedicated to hydrocephalus education and support, such as the Hydrocephalus Association.
Preparing for Your Appointment
Timing of diagnosis depends on the symptoms, when they appeared, and whether there were risk factors during pregnancy or delivery — sometimes hydrocephalus is diagnosed at birth or even before.
Keep all well-baby visits. Healthcare professionals monitor head size, growth rate, muscle strength and tone, coordination, posture, age-appropriate motor skills, and sensory abilities such as vision, hearing, and touch.
Questions You Should Be Ready to Answer
Your healthcare professional will likely ask about: symptoms noticed and when they began; whether symptoms have changed; nausea or vomiting; vision issues; headache or fever; personality changes or increased irritability; changes in school performance; new movement or coordination problems; sleep or energy changes; seizures in an infant; feeding or breathing difficulty in an infant; bladder control loss or frequent urination in older children and adults; recent head injuries; and any newly started medicines.
Conclusion
Hydrocephalus is a serious but treatable condition. Fluid buildup in the brain's ventricles can harm brain tissue at any age, but surgery — a shunt or a small drainage hole — relieves pressure, and most people who are treated early go on to live with few limitations. The most important actions are time-sensitive: treat infants with a high-pitched cry, feeding difficulty, repeated vomiting, or seizures as an emergency, and don't dismiss a shuffling walk, memory loss, and bladder problems in an older adult as ordinary aging — it could be NPH, one of the few reversible causes of dementia-like symptoms.
Don't wait out the warning signs. If you or a loved one has unexplained symptoms that match this article, schedule an appointment with a healthcare professional today. For infants showing emergency signs, seek emergency medical care immediately.
Frequently Asked Questions
What is hydrocephalus in simple terms?
Hydrocephalus is a buildup of cerebrospinal fluid (CSF) in the ventricles deep inside the brain. The extra fluid makes the ventricles larger and presses on brain tissue, which can change thinking, movement, and other functions.
Is hydrocephalus curable?
There is no single "cure," but surgery — most often a shunt or endoscopic third ventriculostomy — drains the extra fluid and controls pressure. When hydrocephalus is mild and treated early, many people have few or no long-term complications.
What are the first signs of hydrocephalus in babies?
In infants, watch for a head larger than usual or growing unusually fast, a bulging or tense soft spot, vomiting, poor feeding, irritability, extreme sleepiness, seizures, and eyes that appear fixed downward. A high-pitched cry, feeding difficulty, repeated vomiting, or seizures require emergency care.
Why does hydrocephalus cause a large head in babies?
Infants' skull bones have not yet fused, so fluid pressure inside the skull makes the head enlarge. A rapidly growing head or a tense, bulging soft spot (fontanelle) is one of the earliest warning signs.
What is normal-pressure hydrocephalus (NPH)?
Normal-pressure hydrocephalus is a type most common in adults 60 and older. The ventricles enlarge but fluid pressure stays in the typical range. It causes a classic triad: memory loss, a shuffling walk (feet feel stuck), and loss of bladder control — and it is one of the few potentially reversible causes of dementia-like symptoms.
How long do you live with a brain shunt?
Most people with hydrocephalus need their shunt for life. Regular checkups are important to confirm the shunt is working well, since shunts can stop draining or become blocked or infected.
Can hydrocephalus be detected before birth?
Yes. Ultrasound placed on the soft spot (fontanelle) is often the first test for babies and is simple and low risk, and hydrocephalus can also be detected before birth during a routine prenatal scan.
What happens if hydrocephalus goes untreated?
Untreated hydrocephalus usually worsens over time and can lead to learning delays, physical or developmental disabilities, or death. Mild cases treated early often cause few or no long-term complications.
References
Health information, not medical advice. This article is for general education and is not a substitute for professional diagnosis or treatment. Always consult a qualified healthcare provider about your own health, and seek emergency care for urgent symptoms.
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