The term “waterhead baby” is an outdated, non-medical phrase for the condition known as hydrocephalus. Hydrocephalus is defined by the abnormal accumulation of cerebrospinal fluid (CSF) within the brain’s ventricles, the fluid-filled cavities deep inside the brain. The excess fluid causes the ventricles to enlarge, exerting pressure on the surrounding brain tissue. This pressure increase requires prompt medical attention to prevent potential brain damage.
The Mechanism of Hydrocephalus
Cerebrospinal fluid (CSF) is a clear, colorless liquid that cushions the brain and spinal cord against impact. It also delivers nutrients and removes metabolic waste products from the central nervous system. CSF is continuously produced primarily by the choroid plexus, a network of specialized capillaries located within the brain’s four ventricles. Normally, the body maintains a balance by producing and absorbing an equal amount of CSF back into the bloodstream.
The fluid circulates through the ventricles and flows around the brain and spinal cord before being reabsorbed. Hydrocephalus occurs when this balance is disrupted, causing the ventricles to swell. The accumulation of fluid results from three main problems: an obstruction blocking the normal flow of CSF, a reduced ability to absorb the fluid back into the blood, or, less commonly, the overproduction of CSF. This increased intracranial pressure compresses neural tissue, leading to neurological impairments if left untreated.
Recognizing Signs of Fluid Buildup
The signs of hydrocephalus depend heavily on the patient’s age, specifically whether the skull bones have fused. In infants, whose skull sutures are not yet fully closed, the primary sign is a rapid increase in head circumference as the skull expands. Parents may also notice a bulging or tense fontanelle, the soft spot on the top of the head. Other common symptoms include excessive sleepiness, increased irritability, persistent vomiting, and noticeably prominent scalp veins.
A characteristic physical sign is a fixed downward gaze, often referred to as “sunsetting eyes.”
In older children and adults, the skull is rigid because the sutures have fused, meaning the excess fluid cannot expand the head. Symptoms are related to increased intracranial pressure compressing the brain, often manifesting as severe headaches, nausea, and vomiting. Other typical signs include:
- Difficulty with balance and coordination
- Changes in gait
- Vision problems, such as blurred or double vision
- Memory loss
- Difficulty concentrating
- General slowing of movements
Factors Leading to Hydrocephalus and Diagnostic Tools
Hydrocephalus is not a single disease but a condition resulting from underlying factors, broadly categorized as congenital or acquired. Congenital hydrocephalus is present at birth, often stemming from genetic abnormalities or developmental disorders during fetal development. A common cause is aqueductal stenosis, a narrowing of the passage between the third and fourth ventricles that blocks CSF flow. The condition is also frequently associated with neural tube defects like spina bifida.
Acquired hydrocephalus develops after birth and can affect people of any age due to injury or illness. Causes include traumatic brain injury, which may lead to bleeding in the brain, or infections like bacterial meningitis. These issues can cause inflammation and scarring that blocks CSF pathways. Brain tumors or cysts can also physically obstruct the normal circulation of the fluid, leading to accumulation.
Diagnosis typically begins with a thorough physical and neurological examination, where a doctor measures an infant’s head circumference over time to check for rapid growth. Imaging tests are then used to confirm enlarged ventricles and determine the underlying cause. Fetal or neonatal ultrasound is often the first test for infants, providing real-time images of the brain’s structure. For older children and adults, computed tomography (CT) scans and magnetic resonance imaging (MRI) provide detailed cross-sectional images.
Treatment Options and Management
Hydrocephalus requires surgical intervention to divert or reduce the excess cerebrospinal fluid, as medications are generally ineffective long-term. The most common procedure is the implantation of a shunt, a flexible system designed to drain the accumulated fluid away from the brain. A shunt consists of a catheter placed in a ventricle, a valve to regulate flow and pressure, and a distal catheter. This catheter channels the CSF to another part of the body, usually the peritoneal cavity in the abdomen, where it is safely absorbed.
A less common but increasingly utilized surgical option for specific cases of obstructive hydrocephalus is the Endoscopic Third Ventriculostomy (ETV). This procedure involves creating a tiny opening in the floor of the third ventricle. This allows the CSF to bypass the obstruction and flow into the subarachnoid space for normal absorption. ETV is typically used when the blockage is in a specific location and avoids the permanent implantation of a foreign device.
While surgery is generally successful, long-term management is necessary because shunts are prone to complications, such as failure due to mechanical blockage or infection. Patients require lifelong monitoring to ensure the shunt is functioning correctly, and revisions are often necessary, especially as children grow. With timely diagnosis and appropriate medical support, many individuals with hydrocephalus lead full and productive lives. They may still require ongoing rehabilitative therapy and educational support.