A diagnosis of dementia can be devastating, especially when symptoms quickly change a person’s behavior, personality and ability to think.
But research from Cedars-Sinai suggests that a small group of people who appear to have a serious form of dementia may instead have a physical problem that can sometimes be repaired.
The condition is a leak of cerebrospinal fluid, or CSF. This clear liquid normally surrounds the brain and spinal cord, helping protect these delicate tissues and supporting the brain inside the skull.
When too much CSF escapes, pressure around the brain can fall. In some people, this causes the brain to shift downward, a problem often described as brain sagging.
Brain sagging can produce unusual and severe symptoms. A person may develop problems with memory and thinking, lose interest in normal activities, behave differently or experience major personality changes.
These symptoms can closely resemble behavioral-variant frontotemporal dementia, or bvFTD. This form of dementia mainly affects brain areas involved in judgment, emotions, social behavior and self-control, and it often begins earlier in life than Alzheimer’s disease.
The problem is that a CSF leak can be difficult to find. Routine scans may show brain sagging but fail to reveal exactly where the spinal fluid is escaping, leaving doctors without a clear target for treatment.
Researchers at Cedars-Sinai examined 21 patients who had brain sagging as well as symptoms resembling bvFTD. They looked especially closely for a type of leak called a CSF-venous fistula, in which spinal fluid escapes through an abnormal connection and drains directly into a vein.
These leaks can be particularly hard to detect with standard imaging. The researchers therefore used specialized scans that track contrast material as it moves through the spinal fluid, helping doctors see leaks that might otherwise remain hidden.
The team found CSF-venous fistulas in nine of the 21 patients. All nine underwent surgery designed to close the abnormal connections and stop the loss of spinal fluid.
The results were striking. After treatment, all nine patients had their brain sagging reversed, and their dementia-like symptoms also disappeared, with improvements in thinking, mood and behavior.
The outcome was very different among the other 12 patients, whose exact leak sites could not be identified. They received treatments that were not directed at a specific leak, and only three experienced relief from their symptoms.
The findings suggest that locating the precise source of a CSF leak can make a major difference. They also show why doctors may need specialized imaging when a patient has both brain sagging and major changes in behavior or thinking.
Certain clues may raise suspicion of low spinal-fluid pressure. These can include severe headaches that become better when lying flat, unusual tiredness, or a previous diagnosis of Chiari malformation, although symptoms can vary considerably between patients.
The researchers are not suggesting that most cases of frontotemporal dementia are caused by CSF leaks. bvFTD is usually a progressive brain disease, but identifying the uncommon patients whose symptoms have a treatable cause could completely change their outlook.
The study was published in Alzheimer’s & Dementia: Translational Research & Clinical Interventions. It highlights an important lesson in dementia care: when symptoms are accompanied by brain sagging or other signs of a possible CSF leak, a deeper search for the cause may uncover a condition that can potentially be treated rather than a progressive disease that cannot be reversed.
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