“Water head” is the informal, historical term for hydrocephalus, which translates literally from Greek as “water on the brain.” This term is misleading because the fluid involved is not water but cerebrospinal fluid (CSF), a clear substance that surrounds the brain and spinal cord. Hydrocephalus is characterized by the abnormal accumulation of CSF within the brain’s cavities. This buildup causes the internal spaces to swell, putting pressure on surrounding brain tissue and requiring prompt medical attention.
The Medical Reality of Hydrocephalus
Hydrocephalus involves a disruption in the normal cycle of cerebrospinal fluid, which is produced, circulated, and absorbed continuously in the brain. CSF is a protective liquid that provides buoyancy for the brain, cushions it from injury, delivers nutrients, and removes metabolic waste products. This fluid is primarily produced by the choroid plexus, located within the brain’s four interconnected cavities, known as ventricles. Hydrocephalus occurs when the amount of CSF produced exceeds the amount absorbed, or when its normal flow is blocked. The excess CSF accumulates within the ventricles, causing them to enlarge and exert harmful pressure on the delicate brain tissues, which can lead to brain damage.
Categorizing the Causes of Fluid Buildup
Hydrocephalus is categorized into two main types based on where the problem occurs in the fluid pathway. Non-communicating hydrocephalus, also known as obstructive hydrocephalus, happens when a physical blockage prevents the flow of CSF through the narrow passages connecting the ventricles. This blockage can occur from conditions like a tumor, a hemorrhage, or a congenital narrowing of a passage, such as the cerebral aqueduct.
In contrast, communicating hydrocephalus occurs when CSF flow is not blocked within the ventricles, but its proper reabsorption into the bloodstream is prevented after it exits the ventricular system. This is often due to inflammation or scarring of the arachnoid granulations, the primary sites for CSF absorption, and can follow an infection like meningitis or a subarachnoid hemorrhage.
Hydrocephalus is also classified by its onset, as either congenital (present at birth due to developmental or genetic factors) or acquired (developing later in life). Acquired hydrocephalus can result from traumatic brain injury, tumors, or diseases.
Identifying Symptoms Across Different Age Groups
The signs of hydrocephalus vary significantly depending on the patient’s age and whether the skull bones have fused together. In infants, whose skull bones have not yet permanently joined, the most noticeable sign is a rapid increase in head circumference, often larger than expected for their age. The soft spot on the top of the head, called the fontanelle, may also appear tense or bulging.
Infants may also exhibit physical symptoms such as persistent vomiting, excessive sleepiness, or irritability. A distinctive sign is the “sunsetting” of the eyes, where the eyes are fixed downward due to the pressure on the brain.
For older children and adults, whose skull bones are fused, the symptoms relate more directly to the increased pressure on the brain tissue. Severe headaches, which may be worse upon waking, are a common complaint. Visual changes, such as blurred or double vision, and difficulties with balance and coordination can also occur. In adults, especially the elderly, hydrocephalus can manifest as cognitive decline, trouble walking, and loss of bladder control.
Modern Approaches to Diagnosis and Treatment
Diagnosis of hydrocephalus begins with a physical examination and a review of the patient’s symptoms, with special attention given to measuring head circumference in infants. To visualize the fluid accumulation and the ventricular system, doctors rely on various imaging techniques. Ultrasound is often used for infants because it is non-invasive and can assess ventricle size before the fontanelle closes.
Magnetic Resonance Imaging (MRI) and Computed Tomography (CT) scans provide detailed images of the brain’s internal structures to confirm the diagnosis and identify the exact location of any obstruction. Surgical intervention is the primary method of treatment to restore the balance of CSF fluid dynamics.
The most common surgical procedure is the implantation of a ventriculoperitoneal (VP) shunt. This system involves placing a thin, flexible tube into a ventricle to divert the excess CSF away from the brain to the abdomen, where it can be safely absorbed into the bloodstream.
An alternative procedure for certain types of obstructive hydrocephalus is the Endoscopic Third Ventriculostomy (ETV). This minimally invasive technique uses an endoscope to create a small opening in the floor of the third ventricle, allowing the CSF to bypass the blockage and flow directly into a space where it can be reabsorbed.