Hydrocephalus in a newborn: symptoms and treatment

Hydrocephalus in newborns is the abnormal accumulation of cerebrospinal fluid within the ventricles of the brain and adjacent spaces, leading to ventricular dilation, increased intracranial pressure, and the risk of brain tissue damage. The condition can be congenital or acquired after birth, and its severity is determined not only by the size of the ventricles but also by the rate of pressure increase and the underlying cause. [1]

In infancy, the clinical picture differs from that of older children: due to the malleability of the skull bones, signs often include rapid growth of head circumference, bulging fontanelle, suture dehiscence, and the "setting sun sign." Early recognition and referral to a specialist are critical for preserving cognitive and motor development. [2]

Causes range from intrauterine anomalies and infections to posthemorrhagic ventricular dilation in extremely premature infants. The approach to diagnosis and treatment is always individualized, taking into account the mechanism of the CSF flow disorder, age, and associated brain damage. [3]

Table 1. What is important for parents to know in the first days

Question	Short answer
What is hydrocephalus?	Excess cerebrospinal fluid dilates the ventricles and puts pressure on the brain.
Why is this dangerous?	Risk of damage to the developing brain and developmental delays
When to sound the alarm	Rapid head growth, bulging fontanelle, downward gaze, vomiting, lethargy
Who to contact	Pediatrician and pediatric neurosurgeon, urgently if alarming signs are present
[4]

Definition and clinical classification

Two basic mechanisms are distinguished: an obstructive variant, in which the outflow of cerebrospinal fluid within the ventricular system is impaired, and a communicating variant, in which the absorption of cerebrospinal fluid is impaired in otherwise patent pathways. In newborns, both mechanisms are possible and are often associated with other brain lesions. [5]

Based on the time of onset, a distinction is made between congenital hydrocephalus, which is detected antenatally or in the first weeks of life, and acquired hydrocephalus, for example, after intraventricular hemorrhage, infection, or tumor. This distinction is important for prognosis and treatment selection. [6]

In clinical practice, posthemorrhagic ventricular dilation is more common in premature infants as a consequence of severe intraventricular hemorrhage. In full-term infants, variants associated with congenital anomalies of the cerebrospinal fluid pathways or post-infectious changes are common. [7]

Table 2. Clinical forms of hydrocephalus in infants

Form	The essence	Typical contexts
Obstructive	Blockage of cerebrospinal fluid outflow within the ventricles	Aqueduct stenosis, cysts, tumors
Communicating	Impaired absorption of cerebrospinal fluid	Post-infectious and post-hemorrhagic conditions
Congenital	It arose before birth	Anomalies in the development of cerebrospinal fluid pathways
Acquired	After childbirth	Hemorrhage, infection, surgical sequelae
[8]

Causes and risk factors

In extremely premature infants, the leading cause is posthemorrhagic ventricular dilation following high-grade hemorrhage. This condition carries the risk of progressively increasing pressure and requires a threshold approach to early intervention to protect the developing brain. [9]

Other causes include congenital malformations of the cerebrospinal fluid pathways, post-infectious changes following intrauterine and early infections, and space-occupying lesions of childhood, including choroid plexus papilloma. These factors should be specifically excluded based on clinical and imaging data. [10]

Antenatal screening for potential problems includes fetal ultrasound and, if indicated, magnetic resonance imaging, which allows for planning of delivery and subsequent care of the child by a multidisciplinary team. [11]

Table 3. Causes of hydrocephalus in newborns

Cause	Mechanism	Tips for the doctor
Hemorrhage in premature infants	Violation of outflow and absorption	History of mechanical ventilation, hemodynamic instability
Congenital anomalies	Mechanical block	Detection by antenatal ultrasound
Infections	Inflammation and malabsorption	Post-infectious adhesions, meningoencephalitis
Plexus tumors	Excessive production of cerebrospinal fluid	Rapid progression of intracranial hypertension
[12]

Symptoms and clinical signs

Classic signs in infants include rapid growth of head circumference, a bulging, tense fontanelle, widely separated sutures, visible veins on the scalp, lethargy, irritability, vomiting, and feeding difficulties. A characteristic "setting sun sign" is a downward gaze. [13]

In the premature infant unit, indirect signs include apnea, bradycardia, decreased feeding tolerance, and developmental delays. Careful daily head circumference measurements and neurological assessments can help identify problems before severe deformities develop. [14]

Table 4. What parents and doctors should focus on

Sign	What does it mean
Head circumference is growing faster than percentile curves	Progression of ventricular dilation is likely
Bulging fontanelle, suture divergence	Signs of increased intracranial pressure
Setting Sun	Pressure on midbrain structures and gaze disturbances
Vomiting, refusal to eat, lethargy	Possible intracranial hypertension
[15]

Diagnostics

The primary imaging modality in infants is ultrasound through the anterior fontanelle. This method allows for safe and dynamic measurement of ventricular size and monitoring of the effectiveness of interventions, including volumetric indicators and indices. [16]

In clinical practice, quantitative metrics are used: the Levene index, the anterior horn width, and the fronto-occipital ratio. These indicators help standardize observation and determine thresholds for action, especially in premature infants. [17]

Magnetic resonance imaging (MRI) using rapid protocols without sedation is used to clarify the anatomy and cause of obstruction. Computed tomography (CT) is limited in use in infants due to radiation exposure. [18]

Table 5. Diagnostic tools and their tasks

Method	Task	Advantage
Ultrasound through the fontanelle	Screening and dynamics	Safe, affordable, repeatable
Quantification of sizes	Threshold solutions	Objective criteria
Magnetic resonance imaging	Clarification of the reason	High anatomical detailing
[19]

Differential diagnosis

Not every enlargement of the head is hydrocephalus. A distinction must be made between external hydrocephalus, with predominantly subarachnoid space dilation, the consequences of intracranial space-occupying processes, and cranial deformation. Clinical presentation, ultrasound imaging, and the rate of change are taken into account. [20]

Choroid plexus tumors may present with progressive intracranial hypertension with rapidly worsening symptoms. Confirmation is possible only with targeted imaging. [21]

Table 6. What can mimic hydrocephalus in an infant

State	Distinguishing features
External hydrocephalus	Subarachnoid spaces are predominantly enlarged
Tumor or cyst	Focal process on visualization, often asymmetry
Skull deformities	No signs of intracranial hypertension on ultrasound
[22]

Treatment of posthemorrhagic ventricular dilation in premature infants

The current strategy is based on thresholds for early intervention when ventricular dimensions reach low but clinically significant limits. In a randomized trial, early intervention at a "low threshold" reduced white matter damage and improved neurological outcomes compared with waiting until a "high threshold." [23]

Temporary methods of CSF drainage include lumbar punctures, ventricular punctures through a reservoir, and subgaleal drainage. The choice depends on the child's body weight, rate of progression, and condition. The goal is to gain time for a safe, definitive solution. [24]

Pharmacological attempts to "dry" CSF using acetazolamide and furosemide in preterm infants are recognized as ineffective and unsafe and are not recommended as a way to avoid shunting. This is reflected in systematic reviews and clinical guidelines. [25]

Table 7. Threshold approach for posthemorrhagic dilation

What to track	When to act	For what
Ventricular size indices	When the "low threshold" is reached	Reduce the risk of brain damage
Clinical signs of pressure	Immediately	Prevent decompensation
Body weight and readiness for surgery	Individually	Determine the window for definitive treatment
[26]

Definitive surgical treatment: bypass and endoscopy

The standard method is ventriculoperitoneal shunting using antibacterial-impregnated catheters and mandatory antibiotic prophylaxis prior to placement. This approach reduces the risk of shunt infection compared to conventional systems. [27]

An alternative in a select group of infants is endoscopic third ventriculostomy combined with choroid plexus cauterization. This method allows some infants, especially those over 2.5 months of age and for certain reasons, to avoid lifelong shunt dependence, although success depends significantly on age and etiology. [28]

In a randomized trial in infants with post-infectious hydrocephalus, cognitive outcomes at 12 months did not differ between shunt and endoscopic approaches, highlighting the need for individual selection and consideration of local team experience.[29]

Table 8. Comparison of final methods

Criterion	Ventriculoperitoneal shunt	Endoscopic third ventriculostomy and plexus cauterization
The main goal	Reliable drainage of cerebrospinal fluid	Restoration of physiological current and reduction of production
Advantages	Wide availability, predictability	Some children have a chance of freedom from shunts
Restrictions	Risk of infection and obstruction	Success depends on age and reason
Prevention of complications	Antibiotics and impregnated catheters	Patient selection, endoscopy experience
[30]

Complications and post-treatment monitoring

The most common shunt problems are infection, obstruction, and overdrainage. Prevention includes standard antiseptics, antibacterial prophylaxis, and the use of impregnated catheters. Parents are taught the signs of shunt "malfunction" and the procedure for immediate treatment. [31]

After endoscopic surgery, the key risk is early ventricular failure and regrowth. Monitoring is based on clinical examination and dynamic low-threshold ultrasound for repeat imaging in case of questionable symptoms. [32]

Table 9. Signs of a possible "shunt problem" at home

Sign	Action
Lethargy, vomiting, refusal to eat	See a doctor or go to the hospital immediately
Rapid growth of head circumference	Unscheduled examination and ultrasound
Redness along the catheter, fever	Rule out shunt infection
The Return of the Setting Sun	Immediate assessment by a specialist
[33]

Rehabilitation and family support

Even with successful CSF monitoring, children require early rehabilitation: monitoring of motor and speech development, corrective programs, and visual screening. Early interventions improve functional outcomes and family quality of life. [34]

The monitoring plan includes regular visits to a pediatrician and pediatric neurosurgeon, dynamic imaging as indicated, and training parents to recognize warning signs. Teamwork among specialists is essential. [35]

Table 10. Mini-plan for the first year after treatment

Sphere	What to do
Neuroscience and development	Assessment of motor skills and speech by age, early correction
Visualization	Ultrasound as planned, if in doubt - earlier
Family education	Signs of decompensation, treatment regimen
Vaccination and care	According to the calendar, without restrictions in a stable condition
[36]

Forecast

The prognosis depends on the cause of hydrocephalus, the age at the start of treatment, and any associated brain damage. Early intervention with "low thresholds" in preterm infants is associated with better neurodevelopment and less white matter damage. [37]

Comparison of bypass and endoscopic approaches shows that cognitive outcomes may be comparable in some groups, but the rate of re-intervention and complication profile differ. The final choice is made on an individual basis. [38]

Table 11. What influences the outcome the most?

Factor	Influence
Etiology and extent of primary brain damage	Determines the ceiling of rehabilitation possibilities
Timeliness of intervention	The earlier, the better the neurodevelopment
Selection and quality of surgical techniques	Reduces the risk of complications and re-interventions
Access to rehabilitation	Improves functional results
[39]

Frequently asked questions

Is it dangerous to wait for head circumference to grow further?
In preterm infants, interventions at low ventricular size thresholds, rather than at severe dilation, have been shown to be beneficial. Delaying intervention increases the risk of brain damage. [40]

Can hydrocephalus be treated with pills to avoid surgery?
No. Acetazolamide and furosemide have shown no efficacy and suboptimal safety in premature infants. This method is not recommended. [41]

How can the risk of shunt infection be reduced?
Standards include preoperative antibiotics and the use of antibacterial-impregnated catheters, which reduce the incidence of infections. [42]

Is endoscopy always better than a shunt?
No. Endoscopic third ventriculostomy with plexus cauterization is not suitable for all infants and depends on the age and cause. In some groups, outcomes are comparable to a shunt; selection is strictly individual. [43]