For 28 days, my son had hydrocephalus and nobody caught it. He was seen by multiple doctors, admitted to hospital, treated for tuberculosis — and the real cause of his deterioration went undetected for nearly a month. He was three and a half years old.
I am not writing this to criticise doctors. I am writing it because I wish someone had written it for me.
Hydrocephalus — the buildup of cerebrospinal fluid (CSF) inside the brain — is a serious neurological condition. It is also one that is frequently missed, delayed in diagnosis, or misattributed to other causes. Understanding why — and knowing what signs to push for — could save your child months of suffering.
What Makes Hydrocephalus Hard to Diagnose
Hydrocephalus does not announce itself with a single distinctive symptom. Its signs are general: headaches, vomiting, irritability, lethargy. These overlap with dozens of other conditions, from common infections to migraines to gastroenteritis.
In infants, the skull is still soft and the fontanelle (the soft spot) can expand to accommodate extra fluid pressure — which means symptoms appear later and more gradually than in older children. In older children, the skull is rigid, so pressure builds faster — but symptoms are still often vague in the early stages.
The condition also presents differently depending on its cause: congenital hydrocephalus (present from birth) looks different from post-infectious hydrocephalus (caused by meningitis or encephalitis), which looks different from hydrocephalus caused by a tumour or haemorrhage.
This variability is exactly why it gets missed.
The Warning Signs That Are Commonly Overlooked
1. Headaches That Are Worse in the Morning
CSF pressure fluctuates with body position and time of day. It tends to be highest in the morning — particularly after sleeping flat, when fluid has had hours to accumulate without the assistance of gravity. A child who wakes up complaining of head pain, or who vomits shortly after waking without other illness symptoms, should raise concern.
This pattern — morning headache, possible morning vomiting, improvement through the day — is frequently attributed to migraines or anxiety. In hydrocephalus, it reflects genuine pressure changes. If your child has this pattern repeatedly, ask specifically about CSF pressure in your next medical appointment.
2. Vomiting Without Nausea or Other Gut Symptoms
Projectile vomiting — occurring suddenly, without preceding nausea, and not associated with diarrhoea or stomach pain — is a neurological symptom, not a gastrointestinal one. It results from pressure on the vomiting centre of the brainstem.
Children with hydrocephalus may vomit suddenly and then feel relatively fine, which causes parents and sometimes doctors to treat it as a stomach bug that resolves itself. The absence of nausea, the suddenness, and the lack of other gut symptoms are the distinguishing features. Document when vomiting occurs, what the child was doing, and whether they complained of head pain beforehand.
3. The “Sunset Sign” in Infants
In infants with elevated intracranial pressure, the eyes can be forced downward so that only the top portion of the iris is visible above the lower eyelid — creating the appearance of a sun setting below the horizon. This is known as the “sunset sign” or “setting sun sign.”
It occurs because the increased pressure affects the area of the brain controlling upward gaze. It is a late sign in acute hydrocephalus — meaning significant pressure has already built up by the time it appears — but it can be subtle and intermittent in early or chronic presentations.
Many parents and even some non-specialist clinicians have not seen this sign before. If you notice your infant’s eyes appearing to be pulled downward, particularly combined with other symptoms, request urgent paediatric or neurology assessment.
4. A Bulging or Tense Fontanelle in Babies
The fontanelle (the soft spot on a baby’s skull) is normally slightly depressed or flat when the baby is calm and upright. A fontanelle that bulges outward, feels tense or hard, or remains elevated even when the baby is sitting up is a sign of elevated intracranial pressure.
Transient bulging during crying is normal. Persistent bulging when the baby is calm is not. This sign is more reliable and significant than many parents realise. If you are unsure whether your baby’s fontanelle appears abnormal, ask a doctor or nurse to assess it specifically — do not assume it will be noticed passively during a routine examination.
5. Abnormal Head Growth in Infants
In babies under 18 months (when the skull sutures have not yet fused), the head can expand in response to increased CSF pressure. A head circumference that is crossing percentile lines upward — growing faster than the body overall — warrants investigation.
Head circumference should be measured at every well-child check up to at least 12 months. If you feel measurements are not being tracked carefully, ask for them explicitly and ask to see the growth chart.
6. Behavioural Changes and Regression
A previously toilet-trained child who begins having accidents. A verbal child who becomes quieter. A social child who becomes withdrawn. A child whose school performance drops suddenly without clear cause.
These behavioural and developmental regressions — particularly when they appear alongside any of the physical symptoms above — can reflect the cognitive and neurological effects of elevated intracranial pressure. They are often attributed to stress, anxiety, or social factors before neurological causes are considered.
In my son’s case, we noticed him becoming less interactive, less playful, in the days before his diagnosis. We mentioned it. It was attributed to the stress of being unwell. In retrospect, it was his brain under pressure.
7. Difficulty Walking or Change in Gait
In older children and adults, one of the classic presentations of normal pressure hydrocephalus (NPH) is a distinctive gait disturbance — short steps, wide stance, feet that appear “stuck” to the floor (magnetic gait). In children, gait changes from hydrocephalus may appear differently: increased clumsiness, falling more than expected, reluctance to walk.
This symptom is included in the classic NPH triad: gait disturbance, cognitive impairment, urinary incontinence. In children, the presentation varies, but gait change combined with other symptoms should prompt neurological evaluation.
8. Irritability in Infants That Cannot Be Explained
A baby who cries persistently, is difficult to console, and has no obvious cause for distress (hunger, discomfort, illness) may be experiencing head pain. Infants cannot report pain — they express it through behaviour.
Persistent, unexplained irritability — particularly in an infant who has had meningitis, a difficult birth, or any other risk factor for hydrocephalus — should be considered a potential neurological symptom until proven otherwise.
When Is a Child at Higher Risk?
Hydrocephalus is not random. Certain children are at significantly elevated risk, and caregivers of these children should be especially alert to the warning signs above:
- After meningitis or encephalitis — bacterial meningitis in particular causes inflammation that can block CSF drainage pathways, leading to post-infectious hydrocephalus. This can develop weeks after the infection appears to have resolved.
- Premature birth — particularly with intraventricular haemorrhage (IVH), which is common in very premature babies and can scar the CSF drainage system.
- After head trauma — significant traumatic brain injury can disrupt CSF circulation.
- With a known Chiari malformation — a structural abnormality where brain tissue extends into the spinal canal, commonly associated with hydrocephalus.
- With spina bifida (myelomeningocele) — approximately 80–90% of children with open spina bifida develop hydrocephalus.
- After brain surgery or tumour removal — hydrocephalus is a known complication of posterior fossa tumours and their treatment.
My son had bacterial meningitis complicated by a brain abscess. Post-infectious hydrocephalus was a known, documented risk of his condition. It took 28 days for anyone to look for it.
What to Say to a Doctor When You Are Concerned
Medical appointments are short. Doctors are busy. If you are concerned about hydrocephalus, you need to say so clearly — not hint at it and hope it is picked up.
Consider saying:
“My child has [relevant history — meningitis, prematurity, etc.]. I am concerned about the possibility of hydrocephalus. Can we specifically assess for elevated intracranial pressure? What imaging would you recommend?”
The most common initial investigations for suspected hydrocephalus in children include:
- Cranial ultrasound — quick, radiation-free, excellent for infants with an open fontanelle. This is how my son was finally diagnosed.
- CT scan — fast, widely available, clearly shows ventricular enlargement. Uses radiation.
- MRI — the most detailed imaging, preferred for planning treatment. Takes longer and often requires sedation in young children.
You have the right to ask for these investigations. A good clinician will either agree that they are warranted, or explain clearly why they are not — and that explanation should make sense to you.
What Happens If Hydrocephalus Is Diagnosed
A diagnosis of hydrocephalus will typically be followed by a referral to a paediatric neurosurgeon. Treatment options include:
- VP shunt — a surgically implanted device that drains excess CSF from the brain to the abdominal cavity. Effective, but subject to complications including blockage and infection.
- ETV (Endoscopic Third Ventriculostomy) — a procedure that creates a natural drainage pathway within the brain. Appropriate for obstructive hydrocephalus in certain patients. Avoids the risks of an implanted device if successful.
- Temporary external drainage — sometimes used in acute presentations while planning definitive treatment.
This diagnosis is frightening. It was the most frightening day of my life. But it was also the day things began to get better — because we finally knew what we were dealing with.
The Final Word
Trust your instincts. Document symptoms carefully: dates, times, duration, what made it better or worse. Learn the warning signs. And if you are ever told “it’s probably nothing” about symptoms that match what you have read here, ask for imaging before accepting that answer.
Twenty-eight days is too long. Your child deserves a faster answer than my son got.
This article is written by Haris Bin Tahir, father of a hydrocephalus and epilepsy survivor, and founder of Brain Care Path. It is based on personal experience and publicly available medical information. It does not constitute medical advice. If you have concerns about your child’s health, seek urgent medical assessment.