Water on the brain looks different in a baby, a teenager and a grandparent
Hydrocephalus means cerebrospinal fluid is piling up in or around the brain. In a newborn, whose skull plates have not fused, the head visibly swells. In an older child it shows up as morning headaches. In someone over 80 it can masquerade as dementia, with shuffling steps and bladder trouble.
Cerebrospinal fluid cushions the brain, feeds it and carries away waste, circulating through the ventricles and spinal cord before draining into the blood. Hydrocephalus results when production and removal fall out of balance: a pathway is blocked, reabsorption fails, or too much fluid is made. The Greek name simply joins 'water' and 'head', and Hippocrates described the condition more than 2,000 years ago.
Causes split into primary and secondary. Up to half of primary cases have genetic roots, and the commonest congenital cause is aqueductal stenosis, a narrowed channel between the third and fourth ventricles. Spina bifida and malformations such as Dandy-Walker and Arnold-Chiari can also disrupt flow. Secondary hydrocephalus follows meningitis, tumours, head injury or bleeding; blood inside the ventricles leads to it in 51 to 89 percent of patients. A separate form, ex vacuo, occurs when brain tissue shrinks, as in Alzheimer's disease, and fluid fills the gap.
Age shapes the signs. Infants may have a fast-growing head, bulging soft spots and eyes that cannot look upward, sometimes called the setting-sun sign. Once the skull is closed, pressure rises instead, giving headaches that tend to be worst on waking after hours lying flat, along with vomiting and gait problems. Affected children often score higher on verbal than performance IQ tests. In older adults, normal pressure hydrocephalus classically brings Hakim's triad: unsteady walking, incontinence and dementia.
The condition affects roughly 0.1 to 0.6 percent of newborns, and normal pressure hydrocephalus may touch up to 6 percent of people over 80. Diagnosis relies on examination and imaging such as CT. Treatment is usually surgical, either a shunt to divert fluid or an endoscopic third ventriculostomy, which has grown more popular. Many people with shunts lead ordinary lives, though infection, breakage and failure are real risks, especially in children, and untreated cases can end in permanent disability or death.
Source: Hydrocephalus
