According to a new study, some people with behavioural-variant frontotemporal dementia (bvFTD), an incurable disorder in which patients lose their capacity to manage their behaviour and deal with daily living activities, may instead have a CSF fluid leak, which is often treatable. The study’s findings, which were published in the peer-reviewed journal Alzheimer’s & Dementia: Translational Research and Clinical Interventions, could lead to a cure.
“Many of these patients experience cognitive, behavioural 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 behavioral-variant frontotemporal dementia with an unknown cause, then no treatment is available. But our study shows that patients with cerebrospinal fluid leaks can be cured if we can find the source of the leak.”
To protect the brain and spinal cord from injury, cerebrospinal fluid (CSF) circulates in and around them. When this fluid spills into the body, it can cause the brain to sag, resulting in dementia symptoms. Many people with brain sagging, which can be discovered by MRI, go misdiagnosed, according to Schievink, who recommends clinicians to take a second look at patients who exhibit telltale signs.
“A knowledgeable radiologist, neurosurgeon or neurologist should check the patient’s MRI again to make sure there is no evidence for brain sagging,” Schievink advised.
Clinicians can also inquire about a history of severe headaches that improve when the patient lies down, excessive sleepiness despite getting enough sleep at night, and whether the patient has ever been diagnosed with a Chiari brain malformation, a condition in which brain tissue extends into the spinal canal. According to Schievink, brain sagging is frequently misdiagnosed as a Chiari malformation.
Even when brain drooping is discovered, locating the site of a CSF leak might be difficult. When fluid leaks through a tear or cyst in the surrounding membrane, it is detectable with contrast media on CT myelogram imaging. Schievink and his colleagues have uncovered a new cause of CSF leak: a CSF-venous fistula.
The fluid leaks into a vein in some circumstances, making it difficult to spot on a standard CT myelogram. To detect these leaks, technicians must do a specific CT scan and watch the contrast medium move through the cerebrospinal fluid.
This imaging approach was employed on 21 patients with brain drooping and symptoms of bvFTD in this investigation, and CSF-venous fistulas were found in nine of those patients. The fistulas in all nine individuals were surgically closed, and their brain sagging and associated symptoms were totally corrected.
“This is a rapidly evolving field of study, and advances in imaging technology have greatly improved our ability to detect sources of CSF leak, especially CSF-venous fistula,” 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 the need for further research to improve detection and cure rates for patients.”
The remaining 12 trial participants were treated with nontargeted therapy aimed to reduce brain sagging, such as implanted systems for infusing the patient with CSF. Only three of these individuals, however, reported improvement from their symptoms.
“Great efforts need to be made to improve the detection rate of CSF leak in these patients,” stated Schievink. “We have developed nontargeted treatments for patients where no leak can be detected, but as our study shows, these treatments are much less effective than targeted, surgical correction of the leak.”
