Hydrocephalus vs. Encephalitis — What's the Difference?

Hydrocephalus involves the excessive accumulation of cerebrospinal fluid (CSF) in the ventricles, or cavities, of the brain. This accumulation can be due to an overproduction of CSF, obstruction of its flow, or problems with its absorption. The increased pressure can cause the ventricles to enlarge, potentially damaging brain tissues. On the other hand, encephalitis is characterized by the inflammation of brain tissues, typically resulting from a viral infection, although bacteria, fungi, and autoimmune responses can also be culprits. This inflammation can lead to symptoms such as fever, headache, confusion, and, in severe cases, seizures and neurological deficits.

Hydrocephalus can be congenital, present at birth due to genetic factors or developmental disorders, or it can be acquired later in life as a result of infections, tumors, traumatic brain injury, or subarachnoid hemorrhage. Whereas encephalitis usually occurs when an infection or, less commonly, an autoimmune reaction leads to the inflammation of brain tissues. Viral infections are the most common cause, with herpes simplex virus being one of the primary culprits.

The treatment for hydrocephalus often involves surgical intervention to divert the flow of CSF and reduce intracranial pressure, typically through the implantation of a shunt system or endoscopic third ventriculostomy (ETV). Treatment for encephalitis focuses on alleviating the symptoms and, when possible, treating the underlying cause. If a virus is the cause, antiviral medications may be administered, alongside supportive care to manage symptoms like fever, seizures, and swelling of the brain.

Symptoms of hydrocephalus can vary but often include an enlarged head in infants, vomiting, sleepiness, irritability, and downward deviation of the eyes. In contrast, encephalitis symptoms may start with fever, headache, and photophobia, and progress to more severe conditions like seizures, confusion, or even coma, reflecting the inflammation's impact on various brain functions.

Both conditions are medical emergencies that can lead to severe outcomes without prompt treatment. While hydrocephalus primarily affects brain structure and function due to physical expansion and pressure, encephalitis affects brain function through inflammatory processes, potentially leading to brain damage and loss of neural connections.