Hydrocephalus is a condition in which an accumulation of cerebrospinal fluid (CSF) occurs within the brain. This typically causes increased pressure inside the skull. Older people may have headaches, double vision, poor balance, urinary incontinence, personality changes, or mental impairment. In babies, it may be seen as a rapid increase in head size. Other symptoms may include vomiting, sleepiness, seizures, and downward pointing of the eyes.
Hydrocephalus can occur due to birth defects or be acquired later in life. Associated birth defects include neural tube defects and those that result in aqueductal stenosis. Other causes include meningitis, brain tumors, traumatic brain injury, intraventricular hemorrhage, and subarachnoid hemorrhage. The four types of hydrocephalus are communicating, noncommunicating, ex vacuo, and normal pressure. Diagnosis is typically made by physical examination and medical imaging.
Hydrocephalus is typically treated by the surgical placement of a shunt system. A procedure called a third ventriculostomy is an option in some people. Complications from shunts may include overdrainage, underdrainage, mechanical failure, infection, or obstruction. This may require replacement. Outcomes are variable, but many people with shunts live normal lives. Without treatment, permanent disability or death may occur.
About one to two per 1,000 newborns have hydrocephalus. Rates in the developing world may be higher. Normal pressure hydrocephalus is estimated to affect about 5 per 100,000 people, with rates increasing with age. Description of hydrocephalus by Hippocrates dates back more than 2,000 years. The word hydrocephalus is from the Greek , meaning 'water' and , meaning 'head'.
Signs and symptoms
The clinical presentation of hydrocephalus varies with chronicity. Acute dilatation of the ventricular system is more likely to manifest with the nonspecific signs and symptoms of increased intracranial pressure (ICP). By contrast, chronic dilatation (especially in the elderly population) may have a more insidious onset presenting, for instance, with Hakim's triad (Adams' triad).
Symptoms of increased ICP may include headaches, vomiting, nausea, papilledema, sleepiness, or coma. With increased levels of CSF, there have been cases of hearing loss due to CSF creating pressure on the auditory pathways or disrupting the communication of inner ear fluid. Elevated ICP of different etiologies have been linked to sensorineural hearing loss (SNHL). Transient SNHL has been reported after the loss of CSF with shunt surgeries. Hearing loss is a rare but well-known sequela of procedures resulting in CSF loss. Elevated ICP may result in uncal or tonsillar herniation, with resulting life-threatening brain stem compression.
Hakim's triad of gait instability, urinary incontinence, and dementia is a relatively typical manifestation of the distinct entity normal-pressure hydrocephalus. Focal neurological deficits may also occur, such as abducens nerve palsy and vertical gaze palsy (Parinaud syndrome due to compression of the quadrigeminal plate, where the neural centers coordinating the conjugated vertical eye movement are located). The symptoms depend on the cause of the blockage, the person's age, and how much brain tissue has been damaged by the swelling.
In infants with hydrocephalus, CSF builds up in the central nervous system (CNS), causing the fontanelle (soft spot) to bulge and the head to be larger than expected. Early symptoms may also include: Eyes that appear to gaze downward Irritability Seizures Separated sutures Sleepiness Vomiting
Symptoms that may occur in older children can include: Brief, shrill, high-pitched cry Changes in personality, memory, or the ability to reason or think Changes in facial appearance and eye spacing (craniofacial disproportion) Crossed eyes or uncontrolled eye movements Difficulty feeding Excessive sleepiness Headaches Irritability, poor temper control Loss of bladder control (urinary incontinence) Loss of coordination and trouble walking Muscle spasticity (spasm) Slow growth (child 0–5 years) Delayed milestones Failure to thrive Slow or restricted movement Vomiting