In December of 2021, television host, Nick Cannon, shared the devastating news with fans: Cannon’s 5-month-old son, Zen Scott Cannon, had died from a brain tumor. The tumor caused a build-up of fluids in the child’s skull called hydrocephalus. The disorder can be inherited or caused by disease or injury.

In his post he said, “Over the weekend I lost my youngest son to a condition called hydrocephalus. That is pretty much a malignant, midline brain tumor—brain cancer,” Cannon said on The Nick Cannon Show, as reported by NBC News. Zen, Cannon’s seventh child, was diagnosed after his father noticed that he had a cough.

According to Cannon, he always noticed his child had a “sinus thing”—he explained it as a cough. Initially, he thought it was some sort of fluid in the baby’s lungs that would eventually get coughed out.

“He always had this really interesting breathing and by the time he was two months old I noticed…he had a nice-sized head—I called it a Cannon head,” he said, referencing the larger shape of his other kids’ heads. “We didn’t think anything about it,” Cannon said. “But I really wanted to take him to the doctor to get the breathing and the sinus things checked out, so we thought it would be a routine process.”

Cannon shared that the doctors said his son’s sinuses looked good, but the infant actually had another condition. “There was fluid that was building up in his head, and that was the cause of [why] his head was starting to get big,” Cannon said.

The root cause of that fluid, Cannon said, was a malignant (i.e., cancerous) brain tumor in Zen’s head. “Immediately, we had to have surgery…we put a shunt in his head and we were hoping for the best,” Cannon said, explaining that the shunt was put in place to drain the fluid out “so his head would be normal and he would be able to function.”

Cannon said that an “interesting turn” came around Thanksgiving of 2021. “The process sped up…and the tumor began to grow a lot faster,” Cannon said.

Because of that, Cannon said he “made an effort to spend the most quality time with Zen” over the weekend—during which he was able to hold his son for the last time. “Not only did we get to see the sunrise, but we got to see the sunset, too,” Cannon said.

“I didn’t know how I was going to handle today,” he continued, as he made his announcement on his eponymous talk show. “But I wanted to grieve with my family.” Cannon also took a moment to thank Zen’s mom, Alyssa, for being “the strongest woman I’ve ever seen.”

Hydrocephalus is an abnormal buildup of fluid in the ventricles (i.e. cavities) within the brain. That extra fluid forces the ventricles to widen and puts pressure on the brain’s tissues.

Under normal circumstances, cerebrospinal fluid (the clear, colorless fluid that protects and cushions the brain and spine) flows through the ventricles, brain, and spinal cord, before being absorbed into the bloodstream. But, when it’s blocked, the fluid can build up and keep the brain from functioning.

That can lead to brain damage and even death. “Your brain needs to have blood and oxygen to survive and, when there’s a blockage of the spinal fluid, it increases the intracranial pressure,” said Charles C. Park, MD, Ph.D., director of The Minimally Invasive Brain and Spine Center at Mercy Medical Center. “Then, your brain is not getting enough oxygen and that’s when it’s deadly.”

It’s difficult to know exactly how many people are typically affected by the condition, given that it has various causes and can happen in children and adults. Reports estimate that it affects approximately one to two in every 1,000 children born in the U.S.

According to a historical analysis of hydrocephalus published in 2022 in the European Journal of Medical Research, symptoms can include:

• Headaches
• Cognitive and developmental changes
• Vision changes
• Sleep disturbances
• Walking issues

Although, symptoms can vary, depending on a person’s age, infants, children, young adults, middle-aged adults, and older adults may all present differently when they have hydrocephalus.

Symptoms of Hydrocephalus in Infants

Symptoms of hydrocephalus in infants can include:

• A rapid increase in head size
• An unusually large head
• A bulge on the soft spot on the top of the head
• Vomiting
• Problems sucking or feeding
• Sleepiness
• Irritability
• Eyes that are fixed downward or are not able to turn outward
• Seizures

Symptoms in Children, Young, and Middle-Aged Adults

Symptoms of hydrocephalus in children, young, and middle-aged adults can include:

• Headache
• Blurred or double vision
• Nausea or vomiting
• Balance problems
• Slowing or loss of developmental progress (ie. walking, talking)
• Vision problems
• A decline in school or job performance
• Poor coordination
• Loss of bladder control and/or frequent urination
• Difficulty remaining awake or waking up
• Sleepiness
• Irritability
• Changes in personality or cognition including memory loss

Symptoms in Older Adults

Symptoms of hydrocephalus in older adults can include:

• Problems walking
• Progressive mental impairment and dementia
• General slowing of movements
• Loss of bladder control or frequent urination
• Poor coordination and balance

Dr. Park said that it’s “very common” for an infant with hydrocephalus to have heads that appear larger than those of other babies, which is what Cannon noticed in his own infant. “In babies, the cranial sutures in the skull have not formed yet,” Dr. Park explained. “The babies have the ability to expand their skull, and that’s why the head becomes big.”

Hydrocephalus can either be present at birth or shortly after delivery (congenital hydrocephalus), or it can develop over time as a result of injury or disease (acquired hydrocephalus). Both types of hydrocephalus have different causes or risk factors.

According to Cannon, his infant son’s hydrocephalus resulted from a malignant brain tumor—brain or spinal cord tumors can increase a person’s risk of acquired hydrocephalus.

Hydrocephalus can occur when a brain tumor blocks the flow of cerebrospinal fluid, causing a buildup of the fluid in the ventricles of the brain.

Causes of Congenital Hydrocephalus

Congenital hydrocephalus may be caused by:

• Inherited genetic abnormalities that block the flow of cerebrospinal fluid
• Developmental disorders such as those associated with birth defects in the brain, spine, or spinal cord
• Complications of premature birth such as bleeding within the ventricles
• Infection during pregnancy (like rubella) can cause inflammation in fetal brain tissue

Risk Factors for Acquired Hydrocephalus

There are a few risk factors for acquired hydrocephalus. For instance, if you or your child develop a brain or spinal cord tumor, that may increase the risk for developing hydrocephalus. Bacterial meningitis, or other infections of the central nervous system, also puts you at risk for hydrocephalus. Additionally, injury or stroke that causes bleeding in the brain may also increase your risk.

There are two surgical treatments specifically for hydrocephalus. The first is a shunt, which is a tube inserted into the brain to drain excess fluid out of the brain and into the chest cavity or abdomen, allowing it to be absorbed into the body.

The other option is a procedure called an endoscopic third ventriculostomy (ETV), which entails placing a tiny hole at the bottom of the third ventricle of the brain so cerebrospinal fluid can drain more easily.

But if something like a tumor is causing hydrocephalus, treatment gets trickier. “Hydrocephalus is usually very treatable with a shunt, but a tumor may not be treatable,” said Santosh Kesari, MD, Ph.D., neuro-oncologist, and director of neuro-oncology at Providence Saint John’s Health Center and chair of the Department of Translational Neurosciences and Neurotherapeutics at Saint John’s Cancer Institute.

When a tumor is present, “hydrocephalus can sometimes be fixed by shrinking the tumor,” Dr. Kesari added.

If it’s left untreated—or if the underlying cause of hydrocephalus can’t be remedied—the condition can be fatal. “[Hydrocephalus] can be deadly as the brain is enclosed in the skull and cannot move if pressure is applied,” said Adam Esbenshade, MD, a pediatric neuro-oncologist and associate professor of pediatrics at Vanderbilt University Medical Center. “If the pressure gets high enough, then the brain can’t do its normal function.”

For uncomplicated cases in which hydrocephalus can be successfully treated, people can recover “almost completely” and go on to have a good quality of life.

Cannon ended his announcement in 2021 by dedicating the show to his “beautiful son, Z,” and offered empathy to those who have gone through or are currently going through similar situations. “You never know what somebody’s going through,” Cannon said. “Hug your people, hug your family, kiss somebody, tell them you love them.”