Revealing the Hidden Leak: A Reversible Cause of Dementia from CSF-venous Fistula
Objective:
To describe a reversible case of dementia secondary to a cerebrospinal fluid (CSF)-venous fistula and to emphasize the importance of advanced imaging in identifying treatable causes of cognitive decline.
Background:
Dementia associated with CSF leaks is a rare presentation and has been termed brain sagging dementia (BSD) or spinal dementia. It is a result of spontaneous intracranial hypotension (SIH) due to CSF leaks. The loss of CSF volume leads to downward displacement of the brain, causing frontotemporal dysfunction. Clinical manifestations may include personality change, executive dysfunction, gait disturbance, and urinary incontinence. Among CSF leak etiologies, CSF-venous fistulas are an underrecognized cause. Following successful leak repair, symptoms are often reversible.
Design/Methods:
Not applicable
Results:
We report a 71-year-old woman with progressive cognitive and behavioral decline initially suspected to have depression-related dementia. MRI revealed diffuse pachymeningeal enhancement and cerebellar tonsillar descent. Lumbar puncture showed low opening pressure. Dynamic myelography localized a CSF–venous fistula at T1–T2 and was successfully treated with transvenous embolization. The patient's cognition improved dramatically and follow-up neuropsychological testing improved. Of note, thirty-three years prior, the patient had transient vertiginous symptoms and sensorineural hearing loss, and then, over a decade later, developed self-limited headaches and word finding difficulty, suggesting a prolonged and intermittent course of CSF-leak related symptoms.
Conclusions:
This case highlights that dementia due to CSF leaks is treatable. It is also particularly unique given the temporal evolution of symptoms and emphasizes the importance of recognizing fluctuating or progressive cognitive decline and subtle signs of intracranial hypotension. Early recognition and targeted imaging, including dynamic digital subtraction myelography for suspected CSF-venous fistulas, are essential for diagnosis. Timely intervention can reverse cognitive decline, distinguishing this syndrome from primary neurodegenerative dementias and underscoring the need to consider CSF leaks in patients with unexplained cognitive or behavioral decline.
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