An interview with Dr. David I. Sandberg, Pediatric Neurosurgeon at Houston’s Children’s Memorial Hospital, about the symptoms, causes, outcomes, and treatments for kids with hydrocephalus, commonly known as “water on the brain.”
Interview by Sara G. Stephens, HFM Managing Editor
DS: Hydrocephalus is a problem in which the fluid in the brain does not circulate properly. The brain is constantly circulating fluid, most of which resides in large fluid spaces in the brain called ventricles. When this fluid is produced but not absorbed properly into the bloodstream, the fluid spaces in the brain become expanded. The brain experiences increased pressure.
HFM: What symptoms should parents watch for?
DS: Symptoms are very much dependent upon age. Some babies are born with very large heads because of hydrocephalus that starts in utero during brain development. In other babies, the head size is normal initially but grows at an abnormally fast rate. This is why, when you take your baby to the pediatrician for a wellness visit, he measures your child’s head circumference then plots the measurement on a curve, just like weight and height measurements. The doctor is checking for development of hydrocephalus, along with other conditions that can affect head growth.
Every baby has a soft spot, called a fontanelle, on her head. When a baby is calm or sleeping with the head upright, the fontanelle should be soft. If this is not the case, the parent should alert the pediatrician, as something might be wrong.
Another thing to watch for are eyes that are sunsetting—fixed down. There might also be vomiting caused from the increased pressure in the brain.
Older kids don’t have fontanelles you can check, but they do have the benefit of communication. They might complain of headaches. They, too, might experience vomiting or lethargy. In the case of these symptoms, your child should be seen promptly by a pediatrician or brought to the Emergency Department if the symptoms are severe.
HFM: How is hydrocephalus diagnosed?
DS: If your pediatrician or specialist has a clinical suspicion of hydrocephalus, he or she may recommend some type of imaging study of your child’s brain, depending on the child’s age. For babies, the most common screening study is an ultrasound of the brain. What’s nice about this method is that it has no radiation exposure; is relatively inexpensive, fast, and painless; and the baby doesn’t have to hold still.
In an older child, you can’t do ultrasound imaging, as it doesn’t work well through bone; an older child’s bones have fused—there’s no fontanelle. For this age group, you can get a CT or MRI scan. A CT scan is quick, taking only a few minutes. The disadvantage is that this type of imaging is associated with considerable radiation exposure. We are more and more aware today of the dangers of radiation, including an increased risk of cancer down the road. An alternative method for screening is the MRI, which presents no radiation exposure and offers much better images of the brain. The disadvantage of MRIs is that they take one hour to complete. An adult can hold still for this amount of time, but four- year-olds will find this challenge impossible, so we have to sedate them. Sedation presents a whole other concern.
There is a very exciting alternative we have initiated at Children’s Memorial Hermann Hospital. It’s a “quick brain” MRI scan that doesn’t include all the usual sequences of MRI scans, but we get enough information and can do it all in two minutes. It’s the best of both worlds: no radiation and no sedation. This imaging is not available at many hospitals. We think it’s important. At most hospitals, the initial screening is a CT scan. Many parents don’t realize that one CT scan has the same radiation exposure as 30-100 chest x-rays, depending upon the parameters of the CT technician, which ranges from scanner to scanner. These scans are very easy for an emergency room doctor to recommend, because they are easy, quick, and require no sedation.
People worry about the radiation that comes from dental x-rays, not realizing what a huge deal a single CT scan is. We’re proud of the fact that we’re doing fewer and fewer CT scans to make our diagnoses.
HFM: What are the dangers of hydrocephalus?
DS: Before the era of modern treatment, hydrocephalus was a fatal disease. Sixty percent or more of those afflicted died, and the majority of survivors had very severe developmental delays. When the disease was diagnosed in babies and untreated, the babies would get enormous heads—up to three times the normal size.
Regarding long-term damage, hydrocephalus presents a broad range of developmental outcomes. My job is to do everything in my power to help kids reach their potential. Some patients are treated and enjoy normal lives, school, college, and all their parents’ dreams. Others experience minor developmental delays. Others can be severely disabled.
Each patient’s outcome is determined by the cause of his particular affliction, whether he receives prompt treatment, whether infections are avoided, and so on.
HFM: Is there a way to prevent hydrocephalus?
DS: There’s nothing we know of that a parent can do to prevent hydrocephalus. In the U.S., the disease has been associated with prematurity. Premature infants have fragile capillaries in their brains. When the babies are born, their capillaries bleed and get into the fluid space in the ventricles and block circulation in the brain.
In many cases, though, you just don’t know.
HFM: Is there a cure for hydrocephalus?
DS: As far as treatment goes, a number of years ago, we saw the first major breakthrough: a ventriculoperitoneal shunt. This is a tube that goes into the ventricle and drains fluid from the brain into another cavity, typically the abdomen. The tube is connected to a valve that regulates how much fluid is drained. Shunts essentially solve the “plumbing problem” of fluid being produced but not absorbed properly due to a blockage somewhere along the path that fluid typically flows. By bypassing this blockage and allowing fluid drainage into another cavity, shunts can save a patient’s life.
Unfortunately, while potentially life-saving, shunts can have many problems. Like your car or air conditioner, or any other device made by humans, the shunt works one day and may not work the next. It may block, break, or become infected. Sometimes you put a shunt in and it works beautifully. In other cases, the patient ends up undergoing many surgeries, because the device continues to have problems.
Many treatment centers still implant shunts in virtually every patient with hydrocephalus. We try to put in as few as possible and treat the patient instead with minimally invasive procedures, especially neuro-endoscopy.
HFM: What is neuro-endoscopy?
DS: “Neuro” means nervous system. An “endoscope” is a little camera that has working channels. We insert these small cameras into fluid spaces of the brain and do lots of things to treat problems. The most common is endoscopic third ventriculostomy. In this procedure, we make a hole in a membrane, which allows us to bypass blockage in the brain and enables fluid to circulate normally. Many patients are spared a shunt, which is a huge deal for them.
There are other treatments, too. If a cyst is the cause of the hydrocephalus, sometimes we make holes in the cyst so fluid is not blocked anymore. This is called an endoscopic cyst fenestration.
Sometimes hydrocephalus is caused by a brain tumor. In these cases, we can often remove the tumor with either an open procedure or with the endoscope. Usually, removing the cause of the hydrocephalus solves the problem, and nothing else needs to be done.
More and more hospitals are starting to offer these treatments. The more frequently a given hospital treats kids with these disorders, the more likely they’ll try such treatments. At a center like ours, we treat a lot of kids with hydrocephalus. We are very thoughtful about trying to come up with creative endoscopic treatments to help patients avoid shunts and their many complications for the duration of their lives.