Discovery of a potential hidden cause of dementia

Summary: Some patients diagnosed with behavioral variant frontotemporal dementia (bv-FTD) may instead suffer from a cerebrospinal fluid leak that results in a sagging brain.

Source: Sinai Cedars Medical Center

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 – may instead be leaking cerebrospinal fluid, which is often treatable.

The researchers say these findings, published in the peer-reviewed journal Alzheimer’s and Dementia: Translational Research and Clinical Interventionscan pave the way for a cure.

“Many of these patients experience such severe cognitive, behavioral and personality changes that they are arrested or placed in nursing homes,” said Wouter Schievink, MD, director of the spinal fluid leak and neurosurgery program. microvascular and professor of neurosurgery at Cedars-Sinai.

“If they have behavioral variant frontotemporal dementia with an unknown cause, 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. .

Cerebrospinal fluid (CSF) circulates in and around the brain and spinal cord to protect them from injury. When this fluid seeps into the body, the brain can collapse, causing symptoms of dementia. Schievink said many patients with brain droop — which can be detected by MRI — go undiagnosed, and he advises clinicians to re-examine patients with telltale symptoms.

“A competent radiologist, neurosurgeon or neurologist should recheck the patient’s MRI to ensure that there is no evidence of brain collapse,” Schievink said.

Clinicians may also ask about a history of severe headache that improves when the patient lies down, significant drowsiness even after adequate nighttime sleep, and whether the patient has ever been diagnosed with a Chiari brain malformation, a condition in which brain tissue extends into the spine. channel. Brain sag, Schievink said, is often mistaken for a Chiari malformation.

Even when brain collapse is detected, the source of a CSF leak can be difficult to locate. When fluid leaks through a tear or cyst in the surrounding membrane, it is visible on CT myelogram imaging using contrast material.

Schievink and his team recently discovered an additional cause of CSF leakage: CSF venous fistula. In these cases, fluid leaks into a vein, making it difficult to see on a routine CT myelogram. To detect these leaks, technicians must use a specialized scanner and observe the moving contrast medium as it travels through the cerebrospinal fluid.

In this study, the researchers used this imaging technique on 21 patients with cerebral collapse and symptoms of bvFTD, and they found venous fistulas in the CSF in nine of these patients. All nine patients had their fistulas surgically closed, and their cerebral collapse and accompanying symptoms were completely reversed.

It shows a brain
Brain sag, Schievink said, is often mistaken for a Chiari malformation. Image is in public domain

“This is a rapidly evolving field of study, and advances in imaging technology have greatly improved our ability to detect sources of CSF leak, particularly CSF vein fistula,” said Keith L. Black, MD, chair of the Department of Neurosurgery and 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 other 12 study participants, whose leaks could not be identified, were treated with non-targeted therapies designed to relieve brain sag, such as implantable systems to infuse the patient with CSF. However, only three of these patients experienced relief from their symptoms.

“Great efforts should be made to improve the CSF leak detection rate in these patients,” Schievink said.

“We have developed non-targeted 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.”

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About this dementia research news

Author: Press office
Source: Sinai Cedars Medical Center
Contact: Press Office – Cedars Sinai Medical Center
Picture: Image is in public domain

Original research: Free access.
“The Reversible Impairment of the Behavioral Variant of Frontotemporal Brain Collapse Syndrome: Challenges and Opportunities” by Wouter I. Schievink et al. Alzheimer’s and Dementia: Translational Research and Clinical Interventions


Reversible impairment of the behavioral variant of frontotemporal brain sag syndrome: challenges and opportunities


Due to loss of cerebral buoyancy, spontaneous cerebrospinal fluid (CSF) leaks cause orthostatic headaches, but can also cause symptoms indistinguishable from behavioral variant frontotemporal dementia (bvFTD) due to a severe cerebral collapse (including the frontal and temporal lobes), as visualized on brain magnetic resonance imaging. However, detecting these CSF leaks may require specialized spinal imaging techniques, such as digital subtraction myelography (DSM).


We performed lateral decubitus DSM under general anesthesia in 21 consecutive patients with frontotemporal dementia cerebral collapse syndrome (4 females and 17 males; mean age 56.2 years). [range: 31–70 years]).


Nine patients (42.8%) had a CSF vein fistula, a recently discovered type of CSF leak that cannot be detected on conventional spinal imaging. All nine patients underwent uneventful surgical ligation of the fistula. Complete or near-complete and sustained resolution of bvFTD symptoms was achieved in all nine patients, accompanied by reversal of brain collapse, but in only three (25.0%) of twelve patients in whom none venous fistula in CSF could not be detected (P = 0.0011), and who were treated with non-targeted therapies.


Concerns about CSF leakage into the spine should not be discounted in patients with frontotemporal sinking brain syndrome, even when conventional spinal imaging is normal. However, even with this specialized imaging, the source of spinal CSF loss remains elusive in more than half of patients.

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