Title : Venous hypertensive encephalopathy presenting as rapidly progressive dementia and parkinsonism secondary to a torcular herophili dural arteriovenous fistula

Background/Objective: Torcular Herophili dural arteriovenous fistulas (DAVFs) are rare intracranial vascular malformations that can produce venous hypertensive encephalopathy (VHE), closely mimicking neurodegenerative or cerebrovascular disease. We report a case illustrating the diagnostic pitfalls of this condition and the reversibility of VHE following endovascular treatment.

Methods/Case: A 70-year-old woman developed subacute, progressive motor slowing, gait instability, and cognitive decline over three months, initially attributed to lacunar ischaemia. Serial MRI showed progressive bilateral white-matter hyperintensity (Fazekas grade 2). Comprehensive investigation — CSF analysis, autoimmune encephalitis panel, MOG-IgG antibodies, oligoclonal bands, and toxicological screening — was unremarkable, and high-dose corticosteroids produced no benefit. She progressed to aphasia and inability to stand. Repeat contrast-enhanced MRI revealed early opacification of the left transverse sinus during the arterial phase, prompting digital subtraction angiography (DSA), which confirmed a torcular Herophili DAVF fed by the left middle meningeal artery and bilateral occipital arteries, draining into the torcular, straight sinus, left transverse sinus, and bilateral deep cerebral veins with retrograde deep venous reflux.

Results: Transarterial embolization with ONYX achieved complete fistula obliteration. At one-month follow-up, MMSE improved from untestable to 23/30, with recovery of speech and mobility, and follow-up MRI demonstrated marked reduction in white-matter signal abnormality, confirming reversal of venous congestion.

Conclusion: Torcular Herophili DAVFs can present as rapidly progressive dementia and Parkinsonism mimicking common neurodegenerative and cerebrovascular syndromes. A disproportionately progressive, treatment-refractory course — particularly the triad of cognitive decline, gait failure, and incontinence — should prompt neurovascular imaging. Early venous opacification on MRI is a key diagnostic clue, and DSA remains essential for diagnosis and treatment planning. Timely endovascular embolization can achieve substantial neurological recovery even after prolonged symptomatic deterioration, underscoring the value of maintaining a broad differential in atypical progressive encephalopathy.

Keywords:

Background/Objective: Torcular Herophili dural arteriovenous fistulas (DAVFs) are rare intracranial vascular malformations that can produce venous hypertensive encephalopathy (VHE), closely mimicking neurodegenerative or cerebrovascular disease. We report a case illustrating the diagnostic pitfalls of this condition and the reversibility of VHE following endovascular treatment.

Methods/Case: A 70-year-old woman developed subacute, progressive motor slowing, gait instability, and cognitive decline over three months, initially attributed to lacunar ischaemia. Serial MRI showed progressive bilateral white-matter hyperintensity (Fazekas grade 2). Comprehensive investigation — CSF analysis, autoimmune encephalitis panel, MOG-IgG antibodies, oligoclonal bands, and toxicological screening — was unremarkable, and high-dose corticosteroids produced no benefit. She progressed to aphasia and inability to stand. Repeat contrast-enhanced MRI revealed early opacification of the left transverse sinus during the arterial phase, prompting digital subtraction angiography (DSA), which confirmed a torcular Herophili DAVF fed by the left middle meningeal artery and bilateral occipital arteries, draining into the torcular, straight sinus, left transverse sinus, and bilateral deep cerebral veins with retrograde deep venous reflux.

Results: Transarterial embolization with ONYX achieved complete fistula obliteration. At one-month follow-up, MMSE improved from untestable to 23/30, with recovery of speech and mobility, and follow-up MRI demonstrated marked reduction in white-matter signal abnormality, confirming reversal of venous congestion.

Conclusion: Torcular Herophili DAVFs can present as rapidly progressive dementia and Parkinsonism mimicking common neurodegenerative and cerebrovascular syndromes. A disproportionately progressive, treatment-refractory course — particularly the triad of cognitive decline, gait failure, and incontinence — should prompt neurovascular imaging. Early venous opacification on MRI is a key diagnostic clue, and DSA remains essential for diagnosis and treatment planning. Timely endovascular embolization can achieve substantial neurological recovery even after prolonged symptomatic deterioration, underscoring the value of maintaining a broad differential in atypical progressive encephalopathy.

Keywords: Dural arteriovenous fistula; torcular Herophili; venous hypertensive encephalopathy; endovascular embolization; dementia mimic; intracranial venous hypertension

Dr. Hamza Maqbool recently completed his Master's degree (MD) in Neurology at Yancheng Clinical College of Xuzhou Medical University, China. He is continuing his research and clinical training under the supervision of Prof. Gao Yang and will shortly begin PhD studies in neurology, with particular interest in cerebrovascular and neurovascular disease, including dural arteriovenous fistulas and venous hypertensive encephalopathy. Prof. Gao Yang is the Dean of the Hospital at Yancheng Clinical College of Xuzhou Medical University, China, where he supervises both Master's and PhD students in neurology. He has extensive clinical and academic experience in neurovascular disease and continues to mentor early-career physicians and researchers, including Dr. Hamzamuktu, in advancing clinical neuroscience.