When you think about the brain, how much it does, how resilient it is, while at the same time how easily it can be damaged through injury or disease, it’s clear that protecting the brain is crucial. It’s why experts advise helmets and other protective gear during contact sports and it’s why so much attention is paid to traumatic brain injury (TBI), concussion, and conditions like chronic traumatic encephalopathy (CTE). So when news reports surfaced about a patient who had cerebrospinal fluid (CSF) leaking out of his head via his ear, it was a big deal. Leaking brain fluid is a potentially deadly condition that can lead to strokes, brain infection and coma.
First it’s important to understand the mechanics of how such a leak could occur. Cerebrospinal fluid surrounds the brain and spinal cord. It’s encased in a membrane called the dura that cushions the brain and spinal cord. If this membrane is damaged in any way, a leak can occur. In the spinal cord, it’s not uncommon to have a leak of CSF after a lumbar puncture test. In the brain, CSF can leak from trauma, disease or just pressure on the skull. The body makes more CSF every day and it’s constantly circulating so there’s no danger of running out, but a persistent leak is a medical emergency. While it’s not a rare occurrence, it’s not all that common either, but doctors and researchers have seen it happening more often recently and some evidence points to the increase in obesity as a factor.
Mark Hoffman, a resident of Akron, Indiana, had a CSF leak that went on for 10 years, which is almost unheard of. Upon waking up, he would notice that his ear was wet and the pillow he used was soaked as well. He saw several doctors, but no explanation could be found. The problem would come and go, but eventually Hoffman’s ear was leaking fluid almost continuously. Finally, he had an answer. A hole had developed in his skull, along the bone shelf that sits over the ear and protects the ear anatomy from the pressure of the brain. Over time, especially in patients who are overweight, this area of the skull can wear out and a hole can form.
In an interview with the Today show, Hoffman’s surgeon, Dr. Rick Nelson, a neurotologist at IU Health and an assistant professor of otolaryngology at Indiana University School of Medicine explained, “Patients are surprised to realize there’s brain fluid leaking out of their ear. Clearly, they are thinking it’s just a standard ear infection when it’s actually a connection between the outside world and their brain.” The link to obesity is thought to have something to do with sleep apnea. Sleep apnea, when a person actually stops breathing momentarily during sleep, is much more common in patients who are obese. When breathing stops, intercranial pressure goes up. Over time, the constant surges in this pressure can weaken the dura and the bones and a leak develops. Nelson told Today that 15 years ago he would do about two of these repair surgeries every year. That number is now up to two to five procedures every month. Nelson explained that the increase in these procedures, specifically among obese patients, is something worth looking at in research, given how dangerous a CSF leak can be. Check out the video below and see how a leak can impact health and what patients need to do.