A new study from Cedars-Sinai suggests that some patients diagnosed with behavioral variant frontotemporal dementia (bvFTD) — an incurable disease that robs patients of their ability to control their behavior and cope with daily living — may instead have Cerebrospinal fluid leak, which is usually treatable.
The researchers said the findings were published in the peer-reviewed journal Alzheimer’s and Dementia: Translational Research and Clinical Interventions, A cure may be indicated.
“Many of these patients experienced such severe cognitive, behavioral and personality changes that they were arrested or placed in nursing homes,” said Wouter Schievink, MD, professor of neurosurgery and director of the Cerebrospinal Fluid Leak and Microvascular Neurosurgery Program at Cedars-Sinai. “If they have unexplained behavioral variant frontotemporal dementia, then there is no cure. But our study shows that patients with CSF leaks can be cured if we can find the source of the leak.”
Cerebrospinal fluid (CSF) circulates in and around the brain and spinal cord to help cushion them from injury. When this fluid seeps into the body, the brain can sag, causing dementia symptoms. Many patients with a sagging brain (which can be detected with MRI) go undiagnosed, Schievink said, advising clinicians to re-examine patients with significant symptoms.
“A knowledgeable radiologist, neurosurgeon, or neurologist should review the patient’s MRI again to make sure there is no evidence of brain ptosis,” Schievink said.
Clinicians can also ask about a history of severe headaches that improve when the patient lies down, marked lethargy even after an adequate night’s sleep, and whether the patient has ever been diagnosed with Chiari encephalopathy, which is A condition in which brain tissue extends into the spinal canal. A drooping brain is often mistaken for a Chiari malformation, Schievink said.
Even when a ptosis is detected, the source of a CSF leak can be difficult to locate. When fluid leaks through a tear in the surrounding membrane or a cyst, it is visible on CT myelography imaging with the help of a contrast agent.
Schievink and his team recently discovered another cause of CSF leakage: CSF venous fistulas. In these cases, fluid seeps into the veins and is therefore difficult to see on a conventional CT myelogram. To detect these leaks, technicians must use specialized CT scans and watch the movement of the contrast agent as it flows through the cerebrospinal fluid.
In this study, the researchers used this imaging technique on 21 patients with brain ptosis and symptoms of bvFTD, and they identified CSF venous fistulas in nine of them. All nine patients had their fistulas surgically closed, and their brain drop and accompanying symptoms were completely reversed.
“This is a rapidly evolving field of research, and advances in imaging technology have greatly improved our ability to detect the source of CSF leaks, especially CSF venous fistulas,” said Keith L. Black, MD, Chief of Neurosurgery. Cedars-Sinai Ruth and Lawrence Harvey Chair of Neuroscience. “This specialized imaging technique is not widely available, and this study suggests that further research is needed to improve detection and cure rates for patients.”
Leaks could not be identified in the remaining 12 study participants who received untargeted treatments aimed at alleviating the sagging brain, such as an implanted system that infuses patients with cerebrospinal fluid. However, only three of these patients experienced remission.
“Major efforts are needed to increase the detection rate of CSF leaks in these patients,” Schievink said. “We have developed non-targeted treatments for patients with undetectable leaks, but as our study shows, these treatments are far less effective than targeted surgical correction of leaks.”
