Hydrocephalus
A condition involving abnormal accumulation of cerebrospinal fluid in the brain's ventricles
Quick Facts
- Type: Neurological Disorder
- ICD-10: G91
- Prevalence: ~1-2 per 1,000 births
- Affected: All ages, most common in infants
Overview
Hydrocephalus is a neurological condition characterized by the abnormal accumulation of cerebrospinal fluid (CSF) within the brain's ventricles. This excess fluid causes the ventricles to enlarge and increases pressure inside the skull, potentially damaging brain tissue. The condition is often referred to as "water on the brain," though the fluid is actually cerebrospinal fluid, not water.
Cerebrospinal fluid normally flows through the ventricular system, bathes the brain and spinal cord, and is absorbed into the bloodstream. In hydrocephalus, this normal flow and absorption process is disrupted, leading to fluid buildup. The condition can be congenital (present at birth) or acquired later in life due to injury, infection, or other medical conditions.
Hydrocephalus affects people of all ages but is most commonly diagnosed in infants and older adults. In infants, the condition may cause rapid head growth because the skull bones haven't yet fused. In older children and adults, the rigid skull cannot expand, so increased pressure can cause serious symptoms and complications. Early diagnosis and appropriate treatment are crucial for preventing permanent brain damage and optimizing outcomes.
Symptoms
The symptoms of hydrocephalus vary significantly depending on the patient's age, the severity of the condition, and how quickly it develops. Symptoms are primarily related to increased intracranial pressure and may differ between infants, children, and adults.
Primary Symptoms
Symptoms in Infants (0-1 year)
- Rapid head growth: Head circumference increases faster than normal
- Bulging fontanelle: Soft spot on top of head appears tense or bulging
- Lack of growth: Poor feeding and failure to thrive
- Irritability: Excessive crying and fussiness
- Sleepiness: Unusual drowsiness or lack of alertness
- Eyes looking downward: "Setting sun" sign where eyes appear to look down
- Developmental delays: Delayed reaching of milestones
Symptoms in Children and Adolescents
- Headache: Often severe and persistent, worse upon waking
- Vomiting: Frequent vomiting, especially in the morning
- Vision problems: Blurred or double vision
- Balance issues: Unsteady walking or frequent falls
- Personality changes: Irritability, confusion, or behavioral changes
- School problems: Difficulty concentrating or declining academic performance
- Seizures: May occur in some cases
Symptoms in Adults
- Chronic headaches: Persistent head pain, often worse in morning
- Walking difficulties: Unsteady gait, feeling like feet are "stuck"
- Memory problems: Difficulty remembering recent events
- Cognitive decline: Problems with thinking and reasoning
- Urinary incontinence: Loss of bladder control
- Depression or mood changes: Emotional and psychological symptoms
- Abnormal movements: Tremors or coordination problems
Emergency Symptoms
Seek immediate medical attention for:
- Sudden, severe headache
- High fever with neurological symptoms
- Loss of consciousness or altered mental state
- Sudden vision loss
- Difficulty breathing
- Severe vomiting that won't stop
- Signs of shunt malfunction in treated patients
Causes
Hydrocephalus results from an imbalance between the production and absorption of cerebrospinal fluid. Understanding the underlying cause is important for determining the most appropriate treatment approach.
Types Based on Cause
Communicating Hydrocephalus:
CSF flow is blocked after it exits the ventricles:
- Impaired absorption: Problem with CSF absorption into bloodstream
- Overproduction: Rarely, too much CSF is produced
- Arachnoid granulation dysfunction: Normal absorption sites don't work properly
Non-communicating (Obstructive) Hydrocephalus:
CSF flow is blocked within the ventricular system:
- Congenital malformations: Birth defects affecting CSF pathways
- Tumors: Masses blocking CSF flow
- Infections: Inflammation causing blockages
- Bleeding: Blood clots obstructing pathways
Congenital Causes (Present at Birth)
- Neural tube defects: Spina bifida, encephalocele
- Aqueductal stenosis: Narrowing of the cerebral aqueduct
- Dandy-Walker malformation: Developmental abnormality of cerebellum
- Arnold-Chiari malformation: Brain tissue extends into spinal canal
- Genetic disorders: X-linked hydrocephalus and other genetic conditions
Acquired Causes (Develop Later)
Infections:
- Meningitis: Bacterial, viral, or fungal brain infections
- Brain abscesses: Localized infections in brain tissue
- Ventriculitis: Infection of the ventricular system
Tumors:
- Brain tumors: Primary or metastatic tumors blocking CSF flow
- Ventricular tumors: Tumors specifically within ventricles
- Spinal cord tumors: Affecting CSF circulation
Bleeding (Hemorrhage):
- Intraventricular hemorrhage: Bleeding into ventricles
- Subarachnoid hemorrhage: Bleeding around brain surface
- Trauma: Head injuries causing bleeding
Other Causes:
- Head trauma: Injury affecting CSF circulation
- Surgery complications: Post-surgical scarring or infection
- Cysts: Fluid-filled sacs blocking CSF flow
- Vascular malformations: Abnormal blood vessels affecting CSF flow
Risk Factors
Several factors may increase the likelihood of developing hydrocephalus:
Prenatal and Birth-Related Factors
- Premature birth: Born before 37 weeks gestation
- Low birth weight: Infants weighing less than 5.5 pounds
- Intrauterine infections: Infections during pregnancy affecting fetal development
- Maternal infections: Rubella, toxoplasmosis, or other infections during pregnancy
- Birth complications: Difficult delivery or birth trauma
- Genetic factors: Family history of neural tube defects
Age-Related Factors
- Infancy: Highest risk period for congenital hydrocephalus
- Adults over 60: Increased risk of normal pressure hydrocephalus
- Premature infants: Higher risk due to immature brain development
Medical Conditions
- Spina bifida: Neural tube defect strongly associated with hydrocephalus
- Brain tumors: Primary or metastatic tumors blocking CSF flow
- Previous brain infections: History of meningitis or encephalitis
- Head trauma: Previous serious head injuries
- Stroke: Brain bleeding or clots affecting CSF circulation
Genetic Risk Factors
- X-linked hydrocephalus: Genetic condition affecting males
- Family history: Relatives with hydrocephalus or neural tube defects
- Chromosomal abnormalities: Certain genetic syndromes
- Consanguinity: Parents who are closely related
Environmental Factors
- Maternal nutrition: Folic acid deficiency during pregnancy
- Exposure to toxins: Environmental toxins during pregnancy
- Maternal illness: Certain infections or illnesses during pregnancy
- Medication use: Certain drugs during pregnancy
Previous Medical History
- Previous brain surgery
- History of brain infections
- Previous head trauma
- Cancer treatment involving the brain
- Shunt complications from previous treatment
Diagnosis
Diagnosing hydrocephalus requires a combination of clinical assessment, neurological examination, and imaging studies. Early and accurate diagnosis is crucial for preventing complications and determining appropriate treatment.
Clinical Assessment
- Medical history: Symptoms, family history, previous illnesses
- Physical examination: Overall health assessment
- Neurological examination: Testing reflexes, coordination, mental status
- Head measurement: Monitoring head circumference in infants
- Developmental assessment: Evaluating milestones in children
Imaging Studies
Primary Imaging:
- CT scan: Quick assessment of ventricular size and brain structure
- MRI: Detailed images of brain anatomy and CSF flow
- Ultrasound: Through fontanelle in infants with open soft spots
Specialized Imaging:
- MRI cisternography: Tracks CSF flow patterns
- Phase-contrast MRI: Measures CSF flow velocity
- SPECT scan: Evaluates brain function and CSF dynamics
Specialized Tests
- Lumbar puncture: Measure CSF pressure and analyze fluid
- Intracranial pressure monitoring: Continuous pressure measurement
- Neuropsychological testing: Assess cognitive function
- Gait analysis: Evaluate walking patterns in adults
Diagnostic Criteria
Radiological Findings:
- Enlarged ventricles relative to brain tissue
- Evans ratio >0.3 (frontal horn width/brain width)
- Ballooning of frontal horns
- Narrowing of CSF spaces over brain surface
Clinical Findings:
- Appropriate symptoms for age group
- Progressive neurological deterioration
- Response to CSF drainage test
Types of Hydrocephalus
- Acute hydrocephalus: Rapid onset with severe symptoms
- Chronic hydrocephalus: Gradual development over time
- Normal pressure hydrocephalus: Normal CSF pressure with enlarged ventricles
- Ex-vacuo hydrocephalus: Ventricular enlargement due to brain tissue loss
Differential Diagnosis
Conditions that may be confused with hydrocephalus include:
- Benign enlargement of subarachnoid spaces in infants
- Brain tumors
- Alzheimer's disease or other dementias
- Brain atrophy from other causes
- Pseudotumor cerebri
Treatment Options
Treatment for hydrocephalus aims to reduce cerebrospinal fluid pressure and prevent further brain damage. The specific approach depends on the type, cause, and severity of the condition.
Surgical Treatments
Shunt Systems:
Most common treatment involving drainage of excess CSF:
- Ventriculoperitoneal (VP) shunt: Drains CSF from brain to abdomen
- Ventriculoatrial (VA) shunt: Drains CSF from brain to heart
- Ventriculopleural shunt: Drains CSF from brain to chest cavity
- Lumboperitoneal shunt: Drains CSF from spine to abdomen
Endoscopic Procedures:
- Endoscopic third ventriculostomy (ETV): Creates alternate CSF pathway
- Choroid plexus coagulation: Reduces CSF production
- Septostomy: Creates opening between ventricles
External Drainage:
- External ventricular drain (EVD): Temporary drainage for acute cases
- Lumbar drain: Temporary spinal fluid drainage
Shunt Components and Function
- Ventricular catheter: Tube placed in brain ventricle
- Valve system: Regulates CSF flow and pressure
- Distal catheter: Tube carries CSF to drainage site
- Reservoir: Allows access for testing or adjustments
Medical Management
Medications:
- Acetazolamide: Reduces CSF production
- Furosemide: Diuretic that may reduce CSF pressure
- Mannitol: Osmotic agent for acute pressure reduction
- Antibiotics: Prevent or treat shunt infections
Supportive Care:
- Pain management for headaches
- Anti-nausea medications
- Seizure medications if needed
- Physical therapy for motor problems
- Occupational therapy for daily living skills
Treatment of Underlying Causes
- Tumor removal: Surgery for brain tumors causing blockage
- Infection treatment: Antibiotics for bacterial infections
- Hemorrhage management: Treating brain bleeding
- Malformation repair: Surgery for structural abnormalities
Emergency Treatment
For acute hydrocephalus with life-threatening symptoms:
- Immediate surgical intervention
- Emergency shunt placement or revision
- External ventricular drainage
- Intensive care monitoring
- Medications to reduce brain pressure
Long-term Management
- Regular follow-up appointments
- Periodic imaging studies
- Shunt function monitoring
- Developmental assessments in children
- Educational support and accommodations
- Rehabilitation services as needed
Prevention
While not all cases of hydrocephalus can be prevented, certain measures can reduce the risk, particularly for congenital forms and those caused by infections or injuries.
Prenatal Prevention
- Folic acid supplementation: Take 400-800 mcg daily before and during pregnancy
- Prenatal care: Regular checkups to monitor fetal development
- Infection prevention: Avoid infections during pregnancy through vaccination and hygiene
- Genetic counseling: For families with history of neural tube defects
- Avoid harmful substances: No alcohol, tobacco, or illicit drugs during pregnancy
Infection Prevention
- Vaccination: Keep up-to-date with vaccines, especially for meningitis
- Hygiene practices: Proper handwashing and food safety
- Prompt treatment: Seek medical care for serious infections
- Safe travel: Precautions in areas with endemic infections
Injury Prevention
- Head protection: Wear helmets during sports and cycling
- Car safety: Use appropriate car seats and seat belts
- Home safety: Prevent falls and head injuries
- Workplace safety: Follow safety protocols in high-risk jobs
Early Detection and Intervention
- Regular checkups: Monitor head growth in infants
- Developmental screening: Watch for delays in children
- Symptom awareness: Know signs of hydrocephalus
- High-risk monitoring: Extra surveillance for at-risk individuals
Secondary Prevention
For those already at risk or with previous hydrocephalus:
- Regular medical follow-up
- Shunt monitoring and maintenance
- Prompt treatment of infections
- Avoiding head trauma
- Compliance with prescribed treatments
Lifestyle Considerations
- Exercise: Regular physical activity as tolerated
- Nutrition: Balanced diet to support overall health
- Education: Learning about the condition and its management
- Support systems: Building networks for ongoing care
When to See a Doctor
Recognizing the signs of hydrocephalus and seeking prompt medical attention is crucial for preventing complications and optimizing outcomes.
Seek Immediate Emergency Care
- Sudden, severe headache unlike any experienced before
- High fever with headache and neck stiffness
- Loss of consciousness or significant confusion
- Sudden vision loss or severe vision changes
- Difficulty breathing or swallowing
- Seizures, especially new-onset seizures
- Signs of shunt malfunction in treated patients
- Projectile vomiting in infants
Schedule Urgent Medical Attention
- Progressive headaches that worsen over time
- Persistent vomiting, especially in the morning
- Changes in personality or behavior
- New or worsening balance problems
- Cognitive changes or memory problems
- Progressive weakness or coordination problems
- Changes in vision or double vision
For Infants and Children
Immediate Care Needed:
- Rapid increase in head size
- Bulging or tense fontanelle (soft spot)
- Persistent vomiting
- Extreme irritability or lethargy
- Feeding difficulties or failure to thrive
- Eyes that consistently look downward
- High-pitched crying
Schedule Appointment:
- Developmental delays or regression
- Changes in sleep patterns
- School performance problems
- Frequent headaches
- Balance or coordination issues
For Adults
Immediate Care:
- Sudden onset of severe headaches
- Rapid cognitive decline
- Loss of bladder control combined with other symptoms
- Sudden difficulty walking
Schedule Appointment:
- Progressive memory problems
- Gradual walking difficulties
- Chronic headaches
- Incontinence with other neurological symptoms
Shunt-Related Concerns
For patients with shunts, seek immediate care for:
- Return of original hydrocephalus symptoms
- Fever with headache
- Redness or swelling along shunt tract
- Abdominal pain with neurological symptoms
- Any sudden change in condition
Follow-up Care
- Regular appointments as scheduled by neurosurgeon
- Periodic imaging studies to monitor condition
- Developmental assessments for children
- Annual comprehensive evaluations
Frequently Asked Questions
While hydrocephalus cannot be "cured" in the traditional sense, it can be effectively managed with proper treatment. Shunt systems and other surgical procedures can successfully control the condition, allowing many people to live normal, productive lives. Early diagnosis and treatment are key to preventing complications and optimizing outcomes.
Shunt longevity varies widely. Some shunts function for many years without problems, while others may require revision within months. On average, about 50% of shunts need revision within 2 years, and many patients require multiple revisions throughout their lifetime. Regular follow-up with a neurosurgeon is essential for monitoring shunt function.
Many children with hydrocephalus can attend regular school and perform well academically. However, some may need special educational services, accommodations, or individualized education plans (IEPs) depending on their specific needs. Early intervention and appropriate support can help maximize educational outcomes.
Most people with shunts can participate in normal activities with some precautions. Contact sports with high risk of head injury may be discouraged. Activities involving rapid altitude changes (like flying or scuba diving) should be discussed with a doctor. Each person's restrictions depend on their specific situation and should be discussed with their neurosurgeon.
Some forms of hydrocephalus have a genetic component, particularly X-linked hydrocephalus and hydrocephalus associated with neural tube defects. However, most cases are not directly inherited. Genetic counseling may be recommended for families with a history of hydrocephalus or related conditions to assess recurrence risks.
References
- Rekate HL. A consensus on the classification of hydrocephalus: its utility in the assessment of abnormalities of cerebrospinal fluid dynamics. Childs Nerv Syst. 2011;27(10):1535-1541.
- Kahle KT, Kulkarni AV, Limbrick DD Jr, Warf BC. Hydrocephalus in children. Lancet. 2016;387(10020):788-799.
- Williams MA, Malm J. Diagnosis and Treatment of Idiopathic Normal Pressure Hydrocephalus. Continuum (Minneap Minn). 2016;22(2):579-599.
- Tully HM, Dobyns WB. Infantile hydrocephalus: a review of epidemiology, classification and causes. Eur J Med Genet. 2014;57(8):359-368.
- Hydrocephalus Association. Guidelines for pediatric hydrocephalus. Clinical Practice Guidelines. 2023.