What is Congenital Hydrocephalus?
Congenital hydrocephalus refers to excessive accumulation of cerebrospinal fluid (CSF) in the brain at birth. The excess fluid can increase pressure in the baby's brain, causing brain injury and mental and physical problems.
CSF is the fluid that surrounds the brain and the spinal cord. It is produced by hollow spaces inside the brain called ventricles. CSF is designed to deliver nutrients to the brain and spinal cord and remove waste products. Normally, this fluid gets absorbed back into the bloodstream, but with hydrocephalus the fluid is produced faster than it can be removed, causing an abnormal accumulation within the brain. This results in enlarged head size and increased pressure on the brain that can be potentially damaging. Newborns with this condition require specialized treatment and care to minimize the risk of brain damage and other difficulties.
Causes of Congenital Hydrocephalus
Typically, congenital hydrocephalus can occur either due to changes that develop during pregnancy or due to genetic factors. Cerebrospinal fluid can accumulate in the brain during and after pregnancy as a result of a combination of spaces in the brain, called ventricles, producing too much CSF, a blockage that prevents the fluid from draining, or an inability of the blood to reabsorb the fluid.
The primary underlying causes for these problems include:
- Genetic variations that cause the development of narrow ventricles in the brain
- The presence of an infection
- The development of a cyst or tumor
- Conditions such as spina bifida, which can block the flow of CSF out of the skull
- The presence of a larger syndrome, such as Dandy-Walker Syndrome, that narrows pathways in the brain
Risk factors for congenital hydrocephalus are still being researched, but potential factors include maternal hypertension, alcohol consumption, and a significant lack of prenatal care.
Signs and Symptoms of Congenital Hydrocephalus
Congenital hydrocephalus can present with a variety of signs and symptoms, and the severity of these symptoms can vary. Here are some common signs and symptoms associated with congenital hydrocephalus:
- Enlarged head (macrocephaly)
- Bulging fontanelle (an outward curving of a spot (fontanelle) of a newborn baby's skull)
- Developmental delays
- Downward looking eyes (sunsetting eyes)
- Irritability
- Vomiting
- Poor feeding
- Seizures
- Changes in muscle tone
- Difficulty with balance and coordination
Diagnosis of Congenital Hydrocephalus
Physicians and other medical professionals are often able to identify potential signs of congenital hydrocephalus during routine ultrasound scans before birth. It can also be found during a physical examination soon after birth where your baby's head is larger than normal. Additional testing, such as magnetic resonance imagery (MRI) and amniotic fluid testing, can assist in positively confirming hydrocephalus. Genetic tests may be done in some cases.
Treatment for Congenital Hydrocephalus
The primary treatment for congenital hydrocephalus often involves surgical intervention to manage the accumulation of cerebrospinal fluid (CSF) and alleviate the associated increased intracranial pressure. The two main surgical approaches are the placement of a ventriculoperitoneal (VP) shunt and an endoscopic third ventriculostomy (ETV).
Of the two, the most common treatment for congenital hydrocephaly is the shunt system. During ventriculoperitoneal shunt placement, a surgeon will place a flexible plastic tube in the baby’s brain to drain the excess fluid. The other end of the tube goes under the skin and into the abdomen, or another area in the body where the additional CSF can be absorbed. The shunt helps maintain normal CSF pressure within the brain and prevents the accumulation of fluid.
Another possible surgical treatment called endoscopic third ventriculostomy is a minimally invasive surgical procedure that involves the use of fiber-optic technology. In this procedure, a surgeon guides a small camera into the baby’s brain and, with a tool, opens a hole in a ventricle, bypassing a blockage. The brain fluid then drains through that hole and is absorbed into the bloodstream. ETV is an alternative to shunt placement and aims to establish a new pathway for CSF drainage. It may be considered in certain cases, depending on factors such as the underlying cause of hydrocephalus and the anatomy of the ventricular system.
Sometimes emergency treatment is required to reduce the fluid. This may include medicines, a lumbar puncture (sometimes called a spinal tap), or a procedure to drain excess fluid from the brain until a shunt can be placed.
