The most common cause of congenital hydrocephalus is aqueductal stenosis, which occurs when the narrow passage between the third and fourth ventricles in the brain is blocked or too narrow to allow sufficient cerebral spinal fluid to drain. Fluid accumulates in the upper ventricles, causing hydrocephalus.Other causes of congenital hydrocephalus include neural-tube defects, arachnoid cysts, Dandy–Walker syndrome, and Arnold–Chiari malformation. The cranial bones fuse by the end of the third year of life. For head enlargement to occur, hydrocephalus must occur before then. The causes are usually genetic, but can also be acquired and usually occur within the first few months of life, which include intraventricular matrix hemorrhages in premature infants, infections, type II Arnold-Chiari malformation, aqueduct atresia and stenosis, and Dandy-Walker malformation. Hydrocephalus has also been seen in cases of congenital syphilis.In newborns and toddlers with hydrocephalus, the head circumference is enlarged rapidly and soon surpasses the 97th percentile. Since the skull bones have not yet firmly joined, bulging, firm anterior and posterior fontanelles may be present even when the person is in an upright position.The infant exhibits fretfulness, poor feeding, and frequent vomiting. As the hydrocephalus progresses, torpor sets in, and infants show lack of interest in their surroundings. Later on, their upper eyelids become retracted and their eyes are turned downwards ("sunset eyes") (due to hydrocephalic pressure on the mesencephalic tegmentum and paralysis of upward gaze). Movements become weak and the arms may become tremulous. Papilledema is absent, but vision may be reduced.
Early symptoms may also include:
Eyes that appear to gaze downward
Irritability
Seizures
Separated sutures
Sleepiness
VomitingSymptoms 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
VomitingBecause hydrocephalus can injure the brain, thought and behavior may be adversely affected. Learning disabilities, including short-term memory loss, are common among those with hydrocephalus, who tend to score better on verbal IQ than on performance IQ, which is thought to reflect the distribution of nerve damage to the brain. Hydrocephalus that is present from birth can cause long-term complications with speech and language. Children can have issues such as nonverbal learning disorder, difficulty understanding complex and abstract concepts, difficulty retrieving stored information, and spatial/perceptual disorders. Children with hydrocephalus are often known in having the difficulty in understanding the concepts within conversation and tend to use words they know or have heard. However, the severity of hydrocephalus can differ considerably between individuals, and some are of average or above-average intelligence. Someone with hydrocephalus may have coordination and visual problems, or clumsiness. They may reach puberty earlier than the average child (this is called precocious puberty). About one in four develops epilepsy. Cause
Congenital
Congenital hydrocephalus is present in the infant prior to birth, meaning the fetus developed hydrocephalus in utero during fetal development.