Introduction 

Macrocephaly, or an abnormally noticeable enlarged head size, can be a distressing finding in infants, young children, and even adults. Among all, hydrocephalus, where excessive fluid builds up within the cavities of the brain, increasing pressure inside the head, has been the most significant neurological cause of macrocephaly. 

While it can arise either at birth (congenital), as benign (harmless) familial malformations or later due to infections, brain injuries, or structural abnormalities, early diagnosis and interventions are crucial to prevent long-term complications such as developmental delays, vision problems, or brain damage to support healthy brain development and protect nerve cells (neurons).  

Thanks to the advanced neuroimaging and surgical treatment options, though the diagnosis of 

hydrocephalus can be overwhelming for many parents and families. It can still be managed effectively by patients.  

So, what signs should parents and individuals look out for? How is hydrocephalus treated and 

What can be expected after intervention? Continue reading, as this may offer you some valuable insights!

Understanding hydrocephalus and macrocephaly 

What is hydrocephalus? 

Hydrocephalus, once known as “water on the brain”, is the abnormal, excessive cerebrospinal fluid (CSF) accumulation inside ventricles, internal, hollow spaces of the brain. CSF, as a clear, colourless fluid that bathes the brain and spinal cord, cushions them from mechanical shocks and injury, also delivers nutrients, and removes waste. 

While CSF is constantly produced, circulated, and reabsorbed into the bloodstream in a healthy brain, the amount produced is generally the same as that of its reabsorption each day whenever the balance is disrupted, either due to blockage of flow (non-communicating, obstructive subtype), overproduction, poor absorption (communicating subtype), or simply an unknown cause with normal pressure (NPH) of various reasons like either congenital spina bifida, premature birth, structural abnormalities, or acquired conditions like head trauma, stroke, brain/ spinal cord tumors, as well as infections like meningitis and encephalitis. 

What is macrocephaly? 

Macrocephaly, in contrast, is a visible sign rather than a potential cause, simply referring to the unusually large head circumference (measurement to the most significant part of the head) compared to the same sex and age (particularly through growth charts of children). 

Macrocephaly may present at birth or become apparent during early infancy or childhood. It can result from a wide variety of causes, ranging from harmless, familial, inherited, larger-than-normal-sized head to genetic conditions, brain infections, or underlying 

neurological circumstances, such as increased intracranial pressure or intracranial haemorrhage, that could indirectly cause hydrocephalus. 

How are the two related to each other?

As too much CSF is kept inside brain tissues, ventricles are enlarged, in turn increasing intracranial pressure, even expanding the overall size of the skull. 

Macrocephaly is a key sign of hydrocephalus, primarily in infants whose skulls are not yet fused. Hence,  it becomes one of its more serious pathological contributing factors.¹

All individuals with hydrocephalus generally have ventricle enlargement; however, not all macrocephalic populations have hydrocephalus. The distinction between benign and concerning causes of head enlargement requires particular careful clinical evaluation and investigations. 

Symptoms and effects of hydrocephalus-related macrocephaly 

Hydrocephalus-related macrocephaly can present with a range of physical, neurological, and emotional signs. While symptoms vary by individual's age and the severity of fluid buildup, early recognition of symptoms can facilitate ​​an accurate diagnosis and prompt treatment for better outcomes.^2,3

Symptoms in infants 

As the skull bones are still soft and unfused in infants, the pressure from excessive cerebrospinal fluid can induce visible head enlargement. A rapidly growing or unusually large head, compared to body size, is often the first noticeable symptom that parents notice. While the soft spot (fontanelle) on top of the head may feel tense or bulge, other symptoms, such as vomiting, poor feeding, excessive sleepiness, irritability, and sunsetting eyes, occur subtly or gradually.^2,3

Symptoms in older children and adults 

In older children or adults, head growth is usually not as noticeable because the skull is fused. Symptoms become more relatable to increased cranial pressure and its associated neurological effects. These include frequent headaches, nausea, blurred or doubled vision (diplopia), constant fatigue, balance and coordination issues, and even poor concentration or short-term memory loss. These may show up indirectly upon declined academic, work performance, or changes in personality and behaviours in school-aged children, teenagers, and adults.^2,3

Normal Pressure Hydrocephalus (NPH), more often seen in older adults, may manifest as difficulty walking (gait disturbances), mild dementia, forgetfulness, as well as the loss of bladder control (urinary incontinence). 

Emotional and social impact 

Beyond physical symptoms, hydrocephalus and visible macrocephaly can negatively impact self-esteem and emotional well-being, especially in children. While they may be teased, excluded socially, and feel different from their peers due to academic decline, communication difficulties, or social challenges. Parents may also feel anxious and uncertain about their child's future, which cannot only emotionally but also financially strain a family. The ongoing medical management, such as therapies or surgeries, may disrupt family routines and social participation. 

Diagnosing hydrocephalus and macrocephaly 

Diagnosing hydrocephalus as a cause of macrocephaly involves a combination of clinical observations, imaging studies, and a specialists evaluation for accuracy to guide appropriate treatment and improve long-term outcomes.  

Initial steps 

The diagnostic process typically begins with the measuring of head circumference in infants or young children. In case the measurement is significantly above age-related norms or increases too rapidly over time. Healthcare providers may also check for any larger scalp veins or recent weight loss. 

In addition, neurological exams are conducted to evaluate vision, motor skills, reflexes, and cognitive function. To see if there are any neurobehavioural or emotional issues and functional impairments that signifies the need of further medical attention². 

Diagnostic tools 

Neuroimaging

Neuroimaging tests are the most preliminary and non-invasive tools for diagnosing hydrocephalus. While a cranial ultrasound is commonly used in infants or young children where their fontanelles (soft spots) are still open, for a non-invasive look at the brain’s ventricles. 

Computed tomography (CT) scans, although requiring radiation exposure, are typically a speedy alternative in emergencies. Nonetheless, magnetic resonance imaging (MRI) scans, either with or without contrast, provide the most detailed images of brain structures, which are useful in identifying and assessing the cause and extent of hydrocephalus,  detecting ventricular enlargement, CSF flow obstruction, or other structural abnormalities more clearly.^2,3

Other medical tests 

Additional medical tests may be used to diagnose hydrocephalus in adults. 

• Spinal tap (lumbar puncture) measures the pressure of CSF with a sample taken for analysis. While confirming NPH and idiopathic intracranial hypertension (IIH), it also rules out secondary hydrocephalus and confirms the appropriateness of a shunt placement
• Intracranial pressure monitoring (ICP) is a small pressure monitor inserted to the brain or ventricles in measuring the pressure and detecting the amount of swelling in the brain
• Fundoscopic exam in viewing the optic nerve at the back of the eye using a special device to detect swelling as pressure elevation of the skull suggests hydrocephalus^2,3

Role of specialists 

A multidisciplinary approach is often necessary for an accurate diagnosis. While pediatricians or general practitioners (GPs) may detect macrocephaly. Neurologists and neurosurgeons responsible for specialized assessment and treatment planning; geneticists or developmental specialists may evaluate for more systemic or inherited causes. 

Differentiating causes 

Despite hydrocephalus, there are still many more cases of macrocephaly such as benign familial macrocephaly, megacephaly, subdural fluid collection, tumours, overgrown skulls, or chronic hematomas, to guide treatment decisions and provide appropriate counselling for individuals and families.  

Treatment and management for hydrocephalus 

While hydrocephalus cannot go away on its own, it can leave permanent, irreversible neurological consequences, even fatal when untreated. Early treatment is critical to prevent it from worsening. 

Primary treatment: surgical interventions 

Currently, brain surgery that manages CSF buildup is the only way to treat hydrocephalus.⁴

Shunt system 

A shunt is the most common medical device used to treat hydrocephalus. It involves the surgical placement of a flexible tube into the brain’s ventricles that drains excessive CSF to other parts of the body (most commonly the abdomen) for natural reabsorption. It helps relieve intracranial pressure and prevent further damage. A valve is also included in the system to regulate the drainage speed and fluid flow.^2,5

Endoscopic third ventriculostomy (ETV) 

Endoscopic third ventriculostomy (ETV) is a minimally invasive brain surgery used to treat certain types of hydrocephalus. Creating a small hole on the skull at the floor of the third ventricle allows CSF to bypass blockage and flow more freely amongst brain tissues. Not requiring the implantation of any external hardware. ETV has been the most effective in cases of obstructive (non-communicating) hydrocephalus and can reduce the need for lifelong device dependence.^2,4,6,7

Post-surgical management and follow-up 

After shunt placement or ETV surgery, individuals are required to have regular follow-ups with neurologists and neurosurgeons to monitor for complications and ensure proper CSF flow. These may include physical and neurological exams, developmental assessments, and periodic imaging, such as MRI or CT scans. Caregivers are also educated to watch for signs of shunt malfunction or infections. 

Non-surgical support 

Non-surgical support for hydrocephalus generally focuses on enhancing daily functioning whilst minimising impairments. These may include physical, occupational, and speech therapy that addresses motor skills, coordination, swallowing and communication challenges. Educational and vocational support can help school-aged children and adults overcome learning and job-related adaptation difficulties. Counselling, psychotherapies, parental and familial education, and community resources to empower individuals and their loved ones. 

Prognosis and quality of life 

With surgery, regular monitoring and supportive care, many people with hydrocephalus can live an everyday and fulfilling life. 

Long-term effects of hydrocephalus can vary greatly among individuals based on the cause, timing of diagnosis, and presence of other conditions. While everyone’s experience is unique, there are still some general chronic problems like learning challenges, visual problems, short-term memory issues, executive functional challenges, which highlight the importance of early diagnosis, intervention, and supportive therapies in proper management.³

Summary 

Navigating the journey of hydrocephalus, as a treatable cause of macrocephaly, can be filled with challenges and uncertainties. Yet, thanks to advanced diagnostic and monitoring technologies, as well as surgical interventions like shunts and endoscopic third ventriculostomy, treatment outcomes are improving. Learning signs of macrocephaly and hydrocephalus like rapid head growth and bulging soft spot in infants, as well as the increased intracranial pressure-related symptoms in older children and adults can promote empathy and awareness for community inclusion, to further promote advocacy for research, funding, and access to specialized care for the affected population to live the best in life.