What is hydrocephalus?
When there’s too much fluid inside or around the brain, your baby will be diagnosed with hydrocephalus. Hydrocephalus is one of the most common congenital anomalies affecting the nervous system, occurring with an incidence of 0.3 to 2.5 per 1,000 live births.
The fluid that surrounds your baby’s brain is called cerebrospinal fluid. When there’s too much fluid, the skull becomes larger. When the baby’s skull increases, there’s extra pressure that’s put on the brain. All this extra pressure affects how your baby’s brain develops.
Hydrocephalus is often present in cases of myelomeningocele (spina bifida), but can develop without myelomeningocele. The factors that cause it may be genetic. Fortunately, there are very effective treatments for hydrocephalus that can reduce many of its complications.
How is the condition diagnosed?
During a prenatal ultrasound between 15 and 35 weeks gestation, your physician can see whether the ventricles in the baby’s brain are enlarged and whether there is evidence of increased pressure within the brain. If so, then hydrocephalus may be diagnosed. Sometimes, the hydrocephalus is not discovered until after your baby is born.
Usually, a fetal MRI is performed next to see more detailed images of the brain. This may reveal an anatomic reason for the hydrocephalus. Occasionally, the ultrasound and MRI show increased levels of cerebrospinal fluid within the brain without evidence of increased pressure on the brain. This condition is referred to as ventriculomegaly and is actually more common than hydrocephalus. Ventriculomegaly is usually caused by a brain injury or improper development, so it is important to differentiate hydrocephalus from ventriculomegaly. Our specialists servicing the Fetal to Newborn Care Center are skilled in making this distinction.
Hydrocephalus during pregnancy is usually managed by observing your baby with regular ultrasounds. At this time, there is no fetal treatment for this disorder. The fetus is watched carefully for signs of distress, which may indicate a need for early delivery. The best way to improve the outcome for the baby is to delay delivery until the baby is as mature as possible. Your doctors will also determine if a vaginal delivery is an option, or if a cesarean birth is recommended due to the size of your baby’s head.
How is hydrocephalus treated?
Hydrocephalus treatment depends on the type of fetal hydrocephalus. Hydrocephalus is usually treated with surgery, after the baby is born. Meanwhile, your doctor will continue to monitor your pregnancy and discuss your treatment options with you. You will be able to meet with our neonatologists, neurologists and neurosurgeons while you are still pregnant to fully discuss your baby’s treatment options. The goal of treatment is to release pressure on the baby’s head and to drain fluid.
In babies who have hydrocephalus, an evaluation after delivery is extremely important. This evaluation will likely include imaging studies, such as a CT, MRI or ultrasound. A detailed neurological exam at birth, along with an examination of the head size and soft spots (fontanels) will be done to verify the diagnosis of hydrocephalus.
If there is increased pressure on the brain at birth, it may be necessary to surgically place a shunt into the baby’s brain. A shunt is a device that allows the pressure in the brain to normalize by draining the fluid into the abdominal cavity, where the fluid can be reabsorbed. By placing this shunt, the pressure in the brain is decreased. The goal of placing this shunt is to allow for normal brain development. Children with ventricular shunts are followed closely by our neurosurgical team throughout childhood.
Two common treatments include:
- Ventriculoperitoneal shunt. In this procedure, a shunt (a plastic tube) will re-direct the fluid inside the brain to the abdomen, where it will be absorbed.
- Endoscopic third ventriculostomy. This procedure is used for babies that have a narrow or blocked channel that leads out of their ventricles (cavities in the brain). During the procedure, the doctor will make an opening in the floor of the baby’s brain. The extra fluid will be released to normal places around the brain where it’s absorbed.
How will hydrocephalus affect my baby during and after surgery?
Depending on your baby’s condition, he or she might be able to go home with you or will spend some time in the newborn intensive care unit (NICU) before surgery.
After surgery, your baby will likely need antibiotics to prevent infection and pain medication. Fluids and nutrients will be given to your baby through an IV. Our neonatologists and neurosurgeons will work together to determine the best plan of care for your baby and let you know what to expect.
This is a condition that needs to be monitored throughout your child’s life. Our team of pediatric specialists will work with you to ensure your child gets enough nutrition and is growing properly.
Photo credit: Centers for Disease Control and Prevention, National Center on Birth Defects and Developmental Disabilities.