Last Updated on November 27, 2025 by Bilal Hasdemir

Hydrocephalus is when too much cerebrospinal fluid builds up in the brain’s ventricles. This can lead to high pressure inside the skull. At Liv Hospital, we aim to give top-notch care to patients from around the world. We support those looking for the latest in medical treatments.

Understanding the causes of hydrocephalus in adults is key to treating it right. Things like head injuries, brain tumors, and infections can cause it. We’ll look at the 13 main reasons for fluid buildup in the brain in adults. This will help us understand hydrocephalus and its effects better.

Key Takeaways

• Hydrocephalus is a condition involving abnormal cerebrospinal fluid accumulation in the brain.
• Liv Hospital provides world-class healthcare for international patients.
• Head injuries, brain tumors, and infections are among the causes of hydrocephalus.
• Understanding the causes is key for effective diagnosis and treatment.
• There are 13 common causes of fluid on the brain in adults.

What Is Hydrocephalus? Understanding Fluid on the Brain

Hydrocephalus happens when too much cerebrospinal fluid (CSF) builds up in the brain’s ventricles. This causes the pressure inside the skull to rise. Knowing how CSF works is key to understanding hydrocephalus.

The Role of Cerebrospinal Fluid in Brain Function

Cerebrospinal fluid is vital for the brain. It cushions the brain, keeps it buoyant, and supplies nutrients. It also helps remove waste and keeps the brain’s chemistry balanced.

The brain makes and moves CSF all the time. The choroid plexus in the ventricles creates CSF. It then flows through the brain and spinal cord, keeping them working right.

How Normal CSF Circulation Works

CSF circulation is complex. It involves making, moving, and absorbing CSF. The choroid plexus in the ventricles makes CSF at a rate of about 0.3-0.4 mL/min.

CSF moves from the lateral ventricles to the third and fourth ventricles. Then, it goes into the subarachnoid space. This movement is driven by pressure and the heartbeat.

The arachnoid villi and granulations absorb CSF. This keeps the balance between making and absorbing CSF. Any problem in this balance can cause hydrocephalus.

Location	Function	Role in CSF Circulation
Lateral Ventricles	Production of CSF	Initial production site
Third Ventricle	CSF flow	Receives CSF from lateral ventricles
Cerebral Aqueduct	Narrow passage for CSF	Connects third and fourth ventricles
Fourth Ventricle	CSF flow into subarachnoid space	CSF exits into subarachnoid space
Arachnoid Villi/Granulations	Absorption of CSF	Absorbs CSF into venous system

Knowing how CSF moves is key to understanding and treating hydrocephalus. Any problem in this balance can lead to too much CSF.

Types of Hydrocephalus That Affect Adults

It’s important for adults with hydrocephalus to know the different types. This knowledge helps in choosing the right treatment. Hydrocephalus is divided based on how it affects cerebrospinal fluid (CSF) flow and its onset.

Communicating vs. Non-Communicating Hydrocephalus

Hydrocephalus is mainly split into two types: communicating and non-communicating. Communicating hydrocephalus happens when CSF can’t flow freely after leaving the ventricles. Yet, the pathways remain open, allowing CSF to move between the ventricles and the subarachnoid space.

Non-communicating hydrocephalus, or obstructive hydrocephalus, occurs when CSF can’t leave the ventricles due to a blockage. This blockage can be caused by tumors, cysts, or birth defects that narrow the passages.

Acute vs. Chronic Hydrocephalus

Hydrocephalus can also be classified by its onset and duration. Acute hydrocephalus develops quickly, often with severe symptoms needing quick medical care. It’s often linked to sudden events like brain bleeds or head injuries.

Chronic hydrocephalus grows slowly over time. It may show up with less obvious symptoms like walking problems, memory loss, and bladder control issues. This is common in Normal Pressure Hydrocephalus (NPH).

Type of Hydrocephalus	Characteristics	Common Causes
Communicating Hydrocephalus	CSF pathways are open; obstruction occurs after CSF exits the ventricles	Meningitis, subarachnoid hemorrhage, head trauma
Non-Communicating Hydrocephalus	Blockage within the ventricular system; prevents CSF from flowing out	Tumors, cysts, congenital abnormalities
Acute Hydrocephalus	Rapid onset; severe symptoms	Subarachnoid hemorrhage, traumatic brain injury
Chronic Hydrocephalus	Gradual onset; subtle symptoms	Normal Pressure Hydrocephalus (NPH), idiopathic

Reasons for Hydrocephalus: The 13 Most Common Causes

Hydrocephalus in adults can come from many sources. Some people are born with it, while others get it from injuries, infections, or other health issues.

Acquired vs. Congenital Causes in Adults

Acquired hydrocephalus happens later in life. It can be caused by head trauma, infections, or tumors. Congenital hydrocephalus is present at birth and may be discovered later. Most adult cases are acquired, not congenital.

Common acquired causes include:

• Traumatic brain injury
• Infections such as meningitis
• Brain tumors or cysts
• Subarachnoid hemorrhage

Congenital causes, though rare in adults, include conditions like aqueductal stenosis or Chiari malformations.

Risk Factors That Increase Vulnerability

Some factors make people more likely to get hydrocephalus. These include:

• Age: Older adults are more at risk
• History of head trauma or neurosurgery
• Infections or inflammatory conditions affecting the central nervous system
• Presence of tumors or cysts in the brain

Knowing these risk factors and causes helps in early diagnosis and treatment of hydrocephalus in adults.

We understand that every patient is different. Finding out the specific cause and risk factors is key to creating a treatment plan that works for them.

Brain Tumors and Space-Occupying Lesions

Hydrocephalus in adults can be caused by brain tumors and space-occupying lesions. These disrupt normal CSF circulation. We will look at how these tumors affect the brain and the types linked to hydrocephalus.

How Tumors Obstruct CSF Pathways

Brain tumors and space-occupying lesions can block CSF flow. CSF obstruction happens when a tumor blocks the brain’s narrow passages or ventricles. This prevents CSF from flowing freely.

Common Tumor Types Associated with Hydrocephalus

Several brain tumors can lead to hydrocephalus, including:

• Meningiomas: These are usually benign tumors from the meninges. They can press on brain structures and block CSF pathways.
• Glioma: Tumors from the brain’s glial tissue. They vary in how aggressive they are and their ability to cause hydrocephalus.
• Medulloblastomas: These are malignant tumors more common in kids but can also affect adults. They often cause obstructive hydrocephalus.
• Metastatic tumors: Tumors that spread to the brain from other parts of the body. They can cause hydrocephalus by blocking or other ways.

Knowing the types of tumors that can lead to hydrocephalus is key for diagnosis and treatment planning.

Traumatic Brain Injury and Head Trauma

Adults with traumatic brain injury face a risk of hydrocephalus. This happens because the injury disrupts the flow of cerebrospinal fluid. Such injuries can come from falls, car accidents, or physical attacks, causing serious health issues.

When someone gets a traumatic brain injury, it can damage brain structures right away. It also messes with the flow of cerebrospinal fluid (CSF). This mess can cause CSF to build up, leading to hydrocephalus.

Mechanisms of Post-Traumatic Hydrocephalus

Post-traumatic hydrocephalus can start in a few ways after a brain injury. One main way is when CSF pathways get blocked by inflammation, blood, or debris. This blockage stops CSF from flowing and being absorbed, causing it to build up.

Another way is when CSF absorption at the arachnoid villi gets messed up. This can happen because of inflammation or bleeding in the subarachnoid space. When CSF can’t be absorbed, it builds up, leading to hydrocephalus.

Timeline for Development After Injury

The time it takes for post-traumatic hydrocephalus to show up can vary a lot. Sometimes, it appears quickly, within days or weeks. But for others, it might take months or even years.

It’s very important to catch and track post-traumatic hydrocephalus early. We suggest that people who have had brain injuries see their doctors regularly. This way, they can watch for signs and symptoms of hydrocephalus.

Knowing how post-traumatic hydrocephalus starts and how long it takes to show up is key. It helps us give the right care and help. By watching for risks and symptoms, we can help those with traumatic brain injuries get better.

Subarachnoid Hemorrhage and Intracranial Bleeding

Subarachnoid hemorrhage is a severe form of bleeding in the brain. It can block the flow of cerebrospinal fluid (CSF), leading to hydrocephalus. When blood enters the subarachnoid space, it can stop CSF from flowing properly. This causes fluid to build up in the brain.

This buildup can increase pressure inside the skull. It can also cause more damage to the brain.

We will look at how subarachnoid hemorrhage affects CSF flow. We will also discuss the differences between acute and delayed hydrocephalus.

How Blood in CSF Impairs Circulation

Blood in the CSF can block its flow in several ways. First, it can irritate the meninges, causing inflammation. This can block the CSF pathways.

Second, blood breakdown products can clog the arachnoid granulations. These are responsible for absorbing CSF. This can severely hinder CSF flow and absorption, leading to hydrocephalus.

Mechanisms of Impaired CSF Circulation:

• Irritation of meninges leading to inflammation
• Blockage of arachnoid granulations by blood breakdown products
• Potential obstruction of CSF pathways

Acute vs. Delayed Post-Hemorrhagic Hydrocephalus

Post-hemorrhagic hydrocephalus can happen quickly or later. Acute hydrocephalus happens soon after the bleeding. It often needs immediate medical help.

Delayed hydrocephalus can occur weeks or months after the bleeding. It may show up with symptoms like gait problems, memory loss, and trouble controlling urine.

Characteristics	Acute Post-Hemorrhagic Hydrocephalus	Delayed Post-Hemorrhagic Hydrocephalus
Onset	Shortly after subarachnoid hemorrhage	Weeks or months after hemorrhage
Symptoms	Rapid deterioration, increased ICP	Gait disturbances, cognitive decline, urinary incontinence
Management	Immediate ventricular drainage	Shunt placement, close monitoring

It’s important to know the difference between acute and delayed hydrocephalus. This helps in managing and treating it properly. We will keep watching patients with subarachnoid hemorrhage for signs of hydrocephalus. We will act quickly when we see them.

Infections of the Central Nervous System

Central nervous system infections can cause hydrocephalus by blocking cerebrospinal fluid (CSF) flow. This is a serious condition that needs quick medical help. We’ll look at how different infections harm the CNS and lead to hydrocephalus.

Bacterial Meningitis and CSF Obstruction

Bacterial meningitis is a severe infection that inflames the meninges. These are the protective membranes around your brain and spinal cord. This inflammation can block CSF flow, causing hydrocephalus. The blockage happens because the inflammation creates exudates that block CSF pathways.

Some common causes of bacterial meningitis include:

• Streptococcus pneumoniae
• Neisseria meningitidis
• Haemophilus influenzae

Viral and Fungal Infections Affecting CSF Flow

Viral and fungal infections can also harm the CNS and cause hydrocephalus. Viral infections like viral meningitis or encephalitis can cause inflammation that blocks CSF pathways. Fungal infections, though rare, can lead to chronic meningitis and hydrocephalus.

Key factors that contribute to hydrocephalus in these infections include:

• Inflammation caused by the infection
• Obstruction of CSF pathways
• Impaired CSF absorption

Post-Infectious Inflammatory Response

The body’s response after an infection is key in developing hydrocephalus. After an infection, the body’s response can cause scarring and adhesions in CSF pathways. This further blocks CSF flow. Understanding this is vital for managing and treating post-infectious hydrocephalus.

We know how important quick action is to prevent long-term neurological damage. By treating the infection and managing inflammation, healthcare providers can lower the risk of hydrocephalus.

Post-Surgical Complications and Iatrogenic Causes

Neurosurgery is often lifesaving but can sometimes cause problems like hydrocephalus. It’s key to know which surgeries are riskier and what symptoms to watch for after surgery.

Neurosurgical Procedures with Highest Risk

Some neurosurgical procedures are more likely to cause hydrocephalus. These include:

• Craniotomies: These are surgeries that open the skull. They can cause inflammation or bleeding that blocks CSF pathways.
• Resective surgeries: These involve removing brain tissue or tumors. They can change how CSF moves, leading to hydrocephalus.
• Shunt placements or revisions: Shunts are used to treat hydrocephalus. But putting them in or changing them can sometimes cause problems, like infection or malfunction, leading to hydrocephalus.

Recognizing Post-Operative Hydrocephalus Symptoms

Spotting hydrocephalus after surgery is important. Patients and doctors should look out for:

1. Increased intracranial pressure: Signs like headaches, nausea, and vomiting can mean hydrocephalus is developing.
2. Altered mental status: Changes in how someone thinks or acts, like confusion or being less responsive.
3. CSF leakage: Fluid leaking from the surgery site or through the nose or ears.
4. Wound complications: Problems like infection or the wound opening up.

It’s vital to catch these symptoms early. We suggest keeping a close eye on patients after surgery, but even more so for those at higher risk. This way, we can spot and treat any problems quickly.

Aqueductal Stenosis and Anatomical Obstructions

Aqueductal stenosis is a key factor in hydrocephalus. It happens when the aqueduct of Sylvius narrows. This aqueduct is important for cerebrospinal fluid (CSF) flow between the third and fourth ventricles.

Congenital vs. Acquired Stenosis

Congenital aqueductal stenosis is present at birth. It can be caused by genetics or developmental issues. Acquired stenosis, by contrast, is caused by things like tumors, infections, or hemorrhages. These can lead to scarring and narrowing of the aqueduct.

How Narrow Passages Block CSF Flow

The narrowing of the aqueduct of Sylvius blocks CSF flow. This leads to CSF buildup in the ventricles. The buildup increases intracranial pressure and can cause hydrocephalus. Symptoms include headaches, nausea, and cognitive problems.

As a neurosurgeon, noted, “Aqueductal stenosis is a significant cause of hydrocephalus. Understanding its cause is key to effective management.”

Treating hydrocephalus caused by aqueductal stenosis often requires surgery. This can include placing a shunt to divert excess CSF or endoscopic procedures to improve CSF flow.

Normal Pressure Hydrocephalus (NPH)

Adults with Normal Pressure Hydrocephalus (NPH) show a unique set of symptoms. NPH is a brain condition where fluid builds up in the brain’s ventricles. This causes pressure on the brain.

The Classic Triad: Gait, Cognition, and Urinary Problems

The symptoms of NPH include gait issues, cognitive problems, and urinary incontinence. Gait disturbance is often the first sign, showing as a slow or shuffling walk. Cognitive issues can range from mild to severe, like Alzheimer’s disease. Urinary incontinence comes later, affecting bladder control.

It’s important to understand these symptoms to diagnose NPH. We’ll look at how they affect a patient’s life.

Why NPH Is Frequently Misdiagnosed as Dementia

NPH is often mistaken for dementia because of similar cognitive symptoms. The brain problems in NPH can look like Alzheimer’s. This makes it hard to tell them apart.

To improve diagnosis, we need to know the differences between NPH and dementia. Recognizing gait issues can help make a correct diagnosis.

Idiopathic vs. Secondary NPH

NPH can be either idiopathic or secondary. Idiopathic NPH happens in older adults without a known cause. Secondary NPH is caused by things like brain injury or infections.

Knowing the cause of NPH helps decide the best treatment. We’ll explore how diagnosis and treatment differ based on the cause.

Less Common Causes of Adult Hydrocephalus

Hydrocephalus in adults can come from many less common causes. These are just as important as the well-known ones for a full diagnosis and treatment. Knowing about these conditions helps us give better care to our patients.

Chiari Malformations and Developmental Abnormalities

Chiari malformations are congenital issues that block cerebrospinal fluid (CSF) flow, causing hydrocephalus. They involve the cerebellum and brainstem sticking into the spinal canal.

Key aspects of Chiari malformations include:

• Structural abnormalities that can cause hydrocephalus
• Often diagnosed in childhood, but can be detected in adulthood
• Sometimes associated with other developmental abnormalities

Autoimmune and Inflammatory Conditions

Autoimmune and inflammatory conditions can lead to hydrocephalus by blocking CSF pathways or reducing its absorption. Examples include:

• Sarcoidosis
• Behçet’s disease
• Autoimmune meningitis

These conditions need careful diagnosis and management to avoid long-term neurological damage.

Metabolic and Toxic Causes

Certain metabolic and toxic conditions can cause hydrocephalus by affecting CSF production or absorption. Examples include:

• Vitamin B12 deficiency
• Toxic exposures (e.g., heavy metals)
• Metabolic disorders (e.g., thyroid dysfunction)

Cause	Description	Mechanism
Chiari Malformations	Congenital anomalies affecting cerebellum and brainstem	Obstruction of CSF flow
Autoimmune Conditions	Sarcoidosis, Behçet’s disease, autoimmune meningitis	Inflammation and obstruction of CSF pathways
Metabolic/Toxic Causes	Vitamin B12 deficiency, heavy metal exposure, thyroid dysfunction	Impaired CSF production or absorption

It’s key to understand the less common causes of hydrocephalus in adults for accurate diagnosis and treatment. By recognizing the many causes, we can offer more complete care for our patients.

Diagnosis and Treatment Options for Adult Hydrocephalus

To find out if an adult has hydrocephalus, doctors use many tools. They look at neuroimaging and do clinical checks. Knowing the diagnosis helps pick the right treatment.

Neuroimaging and Diagnostic Tests

Neuroimaging is key in spotting hydrocephalus. MRI (Magnetic Resonance Imaging) and CT (Computed Tomography) scans show the brain’s ventricles. They help find any issues.

These tests show ventricle size, blockages, and brain structure. Other tests might include:

• Lumbar puncture (spinal tap) to measure cerebrospinal fluid (CSF) pressure
• Cisternography to check CSF flow and absorption
• Neuropsychological tests to check brain function

Surgical Interventions: Shunts and Endoscopic Procedures

Surgery is often needed to treat hydrocephalus. The main surgeries are:

1. Shunt placement: A shunt helps move extra CSF away from the brain.
2. Endoscopic third ventriculostomy (ETV): This creates a new CSF flow path, avoiding blockages.

Both methods aim to lower brain pressure by improving CSF flow.

Monitoring and Managing Complications

After surgery, watching for complications is key. This includes shunt problems or infections. Regular check-ups with doctors are vital to manage these risks.

Handling hydrocephalus well means constant monitoring, lifestyle changes, and sometimes more surgery.

Conclusion: Recognizing Symptoms and Seeking Timely Treatment

It’s vital to spot the signs of hydrocephalus early and get medical help fast. At Liv Hospital, we focus on giving top-notch care to those with hydrocephalus and other complex issues. Starting treatment early can greatly improve a patient’s chances of a better outcome.

Knowing the signs of hydrocephalus is the first step to getting the right treatment. We stress the need to recognize symptoms like memory loss, trouble walking, and bladder control issues. Quick action can lead to better care and more treatment options.

Our team at Liv Hospital is all about delivering top healthcare to international patients. We aim to give care that meets each patient’s specific needs. This way, we ensure the best results for those dealing with hydrocephalus.

FAQ

References:

1. Hydrocephalus Association. (n.d.). Hydrocephalus in adults. https://www.hydroassoc.org/hydrocephalus-in-adults
2. NHS. (n.d.). Hydrocephalus: Causes. National Health Service. https://www.nhs.uk/conditions/hydrocephalus/causes