Possible hidden cause of dementia discovered – Zoo House News
A new Cedars-Sinai study suggests that some patients diagnosed with behavioral variant frontotemporal dementia (bvFTD) — an incurable condition that robs patients of the ability to control their behavior and cope with daily life — could have a CSF leak instead, which is often treatable.
Researchers say these findings, published in the journal Alzheimer’s & Dementia: Translational Research and Clinical Interventions, could point the way to a cure.
“Many of these patients experience cognitive, behavioral, and personality changes so severe that they are arrested or placed in nursing homes,” said Wouter Schievink, MD, director of the Cerebrospinal Fluid Leak and Microvascular Neurosurgery Program and professor of neurosurgery at Cedars-Sinai. “If they have behaviorally variant frontotemporal dementia of unknown cause, no treatment is available. 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 protect them from injury. If this fluid enters the body, the brain can become slack and cause symptoms of dementia. Schievink said many patients with cerebral palsy — which can be detected by MRI — go undiagnosed, and he advises clinicians to look again at patients with tell-tale symptoms.
“A knowledgeable radiologist, neurosurgeon, or neurologist should recheck the patient’s MRI to make sure there are no signs of cerebral relaxation,” Schievink said.
Doctors may also ask about a history of severe headaches that improve when the patient lies down, significant drowsiness even after an adequate night’s sleep, and whether the patient has ever been diagnosed with Chiari brain malformation, a condition in which brain tissue grows into the spine expands channel. Brain sagging, Schievink said, is often mistaken for a Chiari malformation.
Even if brain sag is identified, the source of a CSF leak can be difficult to pinpoint. If the fluid leaks through a tear or cyst in the surrounding membrane, it can be seen on CT myelogram imaging using a contrast agent.
Schievink and his team recently discovered another cause of CSF leaks: CSF venous fistula. In these cases, the fluid leaks into a vein, making it difficult to see on a routine CT myelogram. To detect these leaks, technicians must use a special CT scan and observe the contrast agent in motion as it flows through the cerebrospinal fluid.
In this study, the researchers used this imaging technique in 21 patients with cerebral palsy and bvFTD symptoms, and they detected CSF-venous fistulas in nine of these patients. In all nine patients, the fistulas were surgically closed and their cerebral sagging and associated symptoms were completely reversed.
“This is a rapidly evolving area of study, and advances in imaging technology have greatly enhanced our ability to detect sources of CSF leakage, particularly CSF venous fistulae,” said Keith L. Black, MD, chair of the Department of Neurosurgery and the Ruth and Lawrence Harvey Chair in Neuroscience at Cedars-Sinai. “This specialized imaging is not widely available, and this study suggests that further research is needed to improve detection and cure rates for patients.”
The remaining 12 study participants whose leaks could not be identified were treated with non-targeted therapies aimed at alleviating cerebral slackness, such as implantable systems for infusing the patient with CSF. However, only three of these patients experienced relief from their symptoms.
“A great effort needs to be made to improve the detection rate of CSF leaks in these patients,” said Schievink. “We have not developed targeted treatments for patients who cannot detect a leak, but as our study shows, these treatments are much less effective than targeted surgical repair of the leak.”