Hydrocephalus: Symptoms, Types, Causes and Treatment

Hydrocephalus is a complex neurological disorder that can affect people of all ages, from infancy to advanced age. It is characterized by an abnormal accumulation of cerebrospinal fluid (CSF) in the brain's ventricles, leading to a range of symptoms, varying causes, and multiple treatment avenues. Understanding hydrocephalus requires a holistic view of its clinical presentation, underlying mechanisms, and evolving management strategies. In this article, we'll explore the major aspects of hydrocephalus, integrating current research and clinical insights to provide a comprehensive overview.

Symptoms of Hydrocephalus

Recognizing the symptoms of hydrocephalus is the first step toward timely diagnosis and intervention. Symptoms can differ widely depending on age, the rate of CSF accumulation, and individual differences in physiological tolerance. Early identification is crucial, as hydrocephalus can mimic other neurological conditions or present subtly—especially in adults.

Age Group	Key Symptoms	Unique Features	Sources
Infants	Rapid head growth, bulging fontanelle, vomiting, irritability, drowsiness	Scalp vein distension, sunsetting eyes	3 5 12
Children	Headache, nausea, behavioral change, lethargy	Papilledema, developmental delay	3 5 12
Adults	Gait disturbance, cognitive decline, urinary incontinence	Parkinsonism, movement disorders	1 2 5 9
Elderly (NPH)	Gait apraxia, dementia, incontinence	"Wet, wobbly, and wacky" triad	1 2 5 9

Table 1: Key Symptoms Across Age Groups

Infants: Subtle and Overt Clues

In infants, hydrocephalus commonly presents with rapid head circumference growth, a bulging or tense anterior fontanelle (the "soft spot" on the skull), vomiting, irritability, and excessive sleepiness. Scalp veins may appear distended, and the eyes may deviate downward—a phenomenon known as "sunsetting" 3 5 12. Notably, some infants may show few or no symptoms, underscoring the importance of routine head measurements in early childhood.

Children: Behavioral and Physical Changes

Older children often experience headaches, nausea, changes in behavior or school performance, and lethargy. Clinical signs like papilledema (swelling of the optic disk), coordination problems, and developmental delays can appear, but these symptoms are highly variable 3 5 12. Some children with shunted hydrocephalus or chronic forms may show only subtle changes.

Adults: Cognitive and Motor Disturbances

Adults may present with a unique triad of symptoms: gait disturbance, cognitive impairment, and urinary incontinence—especially in normal pressure hydrocephalus (NPH) 1 2 5 9. Additional findings can include movement disorders such as bradykinesia (slowed movement), parkinsonism, and tremors. These symptoms can be mistaken for other neurodegenerative conditions, leading to misdiagnosis or delayed treatment.

Variability and Diagnostic Challenges

Hydrocephalus can sometimes be "occult," especially in adults, presenting with cognitive and psychiatric changes or subtle motor symptoms without classic signs of increased intracranial pressure 1 2 6. Direct measurement of intracranial pressure or advanced imaging may be required to confirm the diagnosis 3 5.

Types of Hydrocephalus

Hydrocephalus is not a single disease but rather a syndrome with several distinct types, each with its own pathophysiology, clinical features, and implications for management. Understanding these types is essential for selecting appropriate therapies and predicting outcomes.

Type	Main Features	Population Affected	Sources
Congenital	Present at birth, genetic/developmental	Infants, children	5 10 12 13 15
Acquired	Develops after birth, secondary causes	All ages	5 10 12 14
Communicating	Impaired CSF absorption, no obstruction	All ages	6 7 10 11
Non-communicating	Obstruction within ventricular system	All ages	6 7 8 10 11
Normal Pressure (NPH)	Ventricular enlargement, normal CSF pressure	Elderly	1 2 5 6 9
Ex Vacuo	Ventricular enlargement from brain atrophy	Elderly (after injury/stroke)	5

Table 2: Types of Hydrocephalus and Their Features

Congenital Hydrocephalus

Congenital hydrocephalus is present at birth and often results from genetic mutations, abnormal brain development, or perinatal insults such as neural tube defects (e.g., spina bifida, encephalocele) 5 12 13 15. Aqueductal stenosis—narrowing of the aqueduct of Sylvius—is a common cause. Mutations affecting cilia function (e.g., FOXJ1) can disrupt CSF flow, producing hydrocephalus as part of wider syndromes 15.

Acquired Hydrocephalus

Acquired hydrocephalus can occur at any age due to trauma, infection (such as meningitis), tumors, hemorrhage, or as a complication of surgery 5 10 12 14. It may develop rapidly (acute) or progressively (chronic), and the prognosis depends on the underlying cause and speed of intervention.

Communicating vs. Non-communicating Hydrocephalus

• Communicating Hydrocephalus: The CSF pathways are open, but absorption is impaired, often due to subarachnoid hemorrhage, meningitis, or congenital maldevelopment 6 7 10 11.
• Non-communicating (Obstructive) Hydrocephalus: A physical blockage within the ventricular system prevents normal CSF flow—commonly due to aqueductal stenosis, tumors, or cysts 6 7 8 10 11.

Normal Pressure Hydrocephalus (NPH)

NPH is characterized by enlarged ventricles and normal or mildly elevated CSF pressure. It primarily affects older adults and manifests with the classic triad: gait disturbance, dementia, and urinary incontinence 1 2 5 6 9. The underlying mechanism may involve impaired CSF absorption, altered brain compliance, or subtle hydrodynamic changes.

Hydrocephalus Ex Vacuo

This type occurs when brain tissue is lost due to stroke, trauma, or neurodegenerative diseases, and the resulting ventricular enlargement is compensatory rather than due to CSF flow disturbance 5.

Causes of Hydrocephalus

Hydrocephalus can arise from a diverse array of etiologies, encompassing genetic, developmental, infectious, neoplastic, and traumatic factors. Understanding the cause is vital for prognosis and targeted intervention.

Cause Type	Examples	Mechanism	Sources
Genetic/Developmental	Aqueductal stenosis, neural tube defects, ciliopathies	Blocked flow, abnormal brain formation	5 12 13 15
Infection	Meningitis, ventriculitis	Inflammation, scarring, blockage	10 12 14
Hemorrhage	Subarachnoid, intraventricular bleed	Obstructs CSF absorption/flow	5 9 14
Tumor	Intraventricular or brain tumors	Direct obstruction of CSF	6 8 10
Trauma	Head injury, surgical complications	Bleeding, scarring, blockage	5 10 14
Unknown/Idiopathic	Many NPH cases	Unclear, multifactorial	5 9

Table 3: Major Causes of Hydrocephalus

Genetic and Developmental Causes

Genetic mutations can disrupt normal brain and CSF pathway development, leading to congenital hydrocephalus 12 13 15. Mutations in genes that control cilia formation (such as FOXJ1) are particularly important, as motile cilia are essential for CSF movement 15. Neural tube defects like spina bifida often coexist with hydrocephalus due to structural abnormalities that block CSF flow 5 12.

Infectious Causes

Infections such as bacterial meningitis or ventriculitis can cause inflammation and subsequent scarring of the CSF pathways, leading to either communicating or non-communicating hydrocephalus 10 12 14. Post-infectious hydrocephalus is a significant cause in children, especially in low-resource settings.

Hemorrhagic Causes

Bleeding into the brain's ventricular system (e.g., after subarachnoid hemorrhage or intraventricular hemorrhage in premature infants) can obstruct CSF flow or absorption, resulting in hydrocephalus 5 9 14. Inflammatory responses to blood breakdown products can exacerbate the problem.

Tumors and Mass Lesions

Brain tumors, especially those located near the ventricular system (such as in the posterior fossa or third ventricle), can directly block CSF flow, causing obstructive hydrocephalus 6 8 10. Tumor removal may resolve the problem, but sometimes shunting is required.

Traumatic and Surgical Causes

Trauma can lead to bleeding, scarring, or anatomical distortion, all of which may impede CSF circulation 5 10 14. Hydrocephalus may also develop as a complication of brain surgery.

Idiopathic and Multifactorial Causes

In many cases, especially in adults with NPH, the precise cause remains unclear. Multifactorial mechanisms involving subtle vascular, metabolic, and hydrodynamic changes are suspected 9 5.

Treatment of Hydrocephalus

Treatment for hydrocephalus has evolved dramatically over the last century, moving from rudimentary interventions to sophisticated surgical and emerging pharmacological approaches. The goal is to relieve excess CSF pressure, preserve neurological function, and minimize complications.

Treatment	How It Works	Key Considerations	Sources
Shunt Surgery	Diverts CSF to another body cavity (e.g., peritoneum)	Risk of infection, malfunction	1 5 7 9 10 12 16 17
Endoscopic Ventriculostomy	Creates new CSF outflow pathway	Best for obstructive hydrocephalus	12 17
Nonsurgical/Pharmacological	Experimental drugs to reduce CSF production	Limited clinical efficacy	18 19
Valve Technology	Adjustable/autoregulatory flow control	Reduces complications	16 17

Table 4: Main Treatment Approaches

Shunt Surgery

The most common and effective treatment is the surgical placement of a shunt system, which diverts CSF from the ventricles to another body cavity (like the peritoneum or right atrium), where it can be absorbed 1 5 7 9 10 12 16 17. Shunt systems have evolved from simple tubes to sophisticated devices with adjustable valves that regulate CSF flow and reduce the risk of over- or under-drainage 16 17. Despite advances, shunt complications such as infection, blockage, and overdrainage remain challenges.

Endoscopic Third Ventriculostomy (ETV)

ETV is a minimally invasive procedure that creates an opening in the floor of the third ventricle, allowing CSF to bypass obstructions and flow normally. It is particularly effective for obstructive (non-communicating) hydrocephalus, especially in older children and adults 12 17. In some cases, ETV is combined with choroid plexus cauterization to further reduce CSF production.

Advances in Valve Technology

Modern shunt valves may be adjustable, autoregulating, or designed to counteract siphoning effects, leading to better CSF dynamics and fewer complications 16 17. These technological improvements have significantly enhanced patient outcomes and quality of life.

Nonsurgical and Experimental Therapies

While the mainstay of hydrocephalus treatment remains surgical, there is ongoing research into nonsurgical approaches. Drugs that reduce CSF production (such as GLP-1 receptor agonists) or modulate fluid homeostasis have shown promise in animal models 18, but have yet to demonstrate robust efficacy in humans 19. Acetazolamide and other diuretics have limited, short-term utility and are not a substitute for surgery 19.

Complications and Long-term Management

Ongoing care is essential, as shunt malfunction, infection, or overdrainage can occur years after initial treatment 5 10. Children with hydrocephalus require regular monitoring for developmental progress and shunt function, while adults and elderly patients need surveillance for cognitive and motor symptoms.

Conclusion

Hydrocephalus is a multifaceted disorder with varied presentations, causes, and treatment strategies. Early recognition and intervention are critical for optimal outcomes.

Key Points:

• Symptoms are age-dependent, ranging from rapid head growth in infants to cognitive and gait disturbances in adults and the elderly.
• Types of hydrocephalus include congenital, acquired, communicating, non-communicating, normal pressure (NPH), and ex vacuo forms.
• Causes are diverse—genetic, developmental, infectious, hemorrhagic, neoplastic, traumatic, or idiopathic.
• Treatment is primarily surgical (shunt or endoscopic), with ongoing innovations in valve technology and experimental pharmacological approaches.

Continued research, technological innovation, and heightened clinical awareness promise to further improve the lives of individuals affected by hydrocephalus.