Hydrocephalus happens when cerebrospinal fluid (CSF) accumulates in the brain. The ventricles, which are connected cavities inside the brain, produce CSF. This fluid cushions and nourishes the brain. In individuals with hydrocephalus, these ventricles grow larger than usual and contain an excess of CSF.
This condition can affect people of all ages, but it’s most common in infants and older adults. In the U.S., about 1 in every 1,000 babies is born with hydrocephalus. Among those over 80 years old, around 40 out of 1,000 experience a specific type known as normal pressure hydrocephalus (NPH).
There are two primary forms of hydrocephalus: communicating and non-communicating (also called obstructive). Communicating hydrocephalus includes normal pressure hydrocephalus and hydrocephalus ex-vacuo. Hydrocephalus can also be categorized as primary (intrinsic or congenital) or secondary (extrinsic or acquired). It’s critical to differentiate between chronic and acute hydrocephalus, as the latter requires immediate medical attention.
Symptoms of hydrocephalus can vary depending on age, cause, other health issues, and intensity. Infants might show signs like seizures, sleepiness, or irritability. Older children and adults with hydrocephalus can exhibit similar symptoms, along with additional ones. For adults with NPH, the main symptoms can take a long time to develop, sometimes months or even years.
Acute hydrocephalus is a medical emergency. It can lead to the brain pressing against the skull, resulting in severe outcomes like coma or cardiac arrest. CSF normally flows through the brain’s ventricles and channels, eventually absorbed into blood vessels and returned to the heart. Disruptions in this flow or absorption can lead to hydrocephalus, causing ventricles to enlarge.
Children with primary hydrocephalus may have genetic syndromes or birth defects affecting brain and ventricle development. However, some infants develop hydrocephalus without known causes. Secondary hydrocephalus in children often follows a brain bleed, particularly premature infants who are at high risk. Infections like meningitis can cause ventricles to block or scar due to inflammation or debris. Trauma, such as a brain injury, or cancer can also be factors.
The reason behind NPH isn’t well understood, which is why it’s sometimes called idiopathic NPH. Scientists think irregular CSF flow might stress brain tissue and blood vessels, reducing blood flow and contributing to symptoms.
Diagnosing hydrocephalus requires distinguishing it from other conditions with similar symptoms. Doctors conduct thorough medical histories, physical exams, and fundoscopic exams to assess brain pressure. Sometimes, an initial ultrasound can help diagnose hydrocephalus, although more detailed imaging with an MRI or CT scan is usually necessary. A lumbar puncture may also be used to gather additional information about the condition.
Treatment varies based on cause, severity, and age. Generally, surgery is necessary to address hydrocephalus, although non-surgical methods might provide temporary relief by reducing CSF pressure. Permanent solutions often involve implanting a shunt to redirect excess fluid. A common procedure is the ventriculoperitoneal shunt, guiding CSF from the brain to the abdomen. Another option is endoscopic third ventriculostomy, which is less invasive and involves creating a pathway for fluid drainage.
People with hydrocephalus may also experience conditions like epilepsy. About 20% of those who receive shunt treatment still face epilepsy symptoms. Other neurological complications may persist as well. Infants with congenital hydrocephalus often have additional conditions like spina bifida.
The prognosis varies widely. Infants with severe hydrocephalus might endure significant challenges, while those with milder cases can lead healthy lives post-treatment. Shunting helps alleviate symptoms for 60% to 80% of NPH patients, sometimes eliminating them entirely. Prompt diagnosis is crucial, as delayed detection can affect treatment effectiveness. It’s important to monitor for shunt malfunctions and seek medical help for any recurring symptoms.
