Title : Venous hypertensive encephalopathy presenting as rapidly progressive dementia and parkinsonism secondary to a torcular herophili Dural arteriovenous fistula: A reversible stroke mimic
Abstract:
Background: Dural arteriovenous fistulas (DAVFs) involving the torcular Herophili are rare intracranial vascular malformations that may produce venous hypertensive encephalopathy (VHE). Because patients frequently present with cognitive decline, gait disturbance, and parkinsonian features, they are often misdiagnosed as neurodegenerative disease or ischemic stroke, delaying definitive treatment.
Case Presentation: We report a 70-year-old woman who developed rapidly progressive cognitive decline, gait instability, parkinsonism, and aphasia over three months. Initial brain CT suggested lacunar ischemia, while serial MRI demonstrated progressive bilateral white-matter hyperintensities. Extensive investigations, including cerebrospinal fluid analysis, autoimmune encephalitis antibodies, toxicology screening, and metabolic evaluation, were unrevealing, and high-dose corticosteroid therapy failed to improve her condition. Repeat contrast-enhanced MRI identified early arterial-phase opacification of the left transverse sinus, raising suspicion for a vascular shunt. Digital subtraction angiography confirmed a torcular Herophili dural arteriovenous fistula supplied by branches of the left middle meningeal and bilateral occipital arteries with retrograde deep venous drainage. The patient underwent successful transarterial ONYX embolization, achieving complete angiographic obliteration of the fistula.
Results: One month after treatment, the patient demonstrated remarkable neurological recovery. Cognitive function improved from an untestable state to a Mini-Mental State Examination score of 23, speech and gait significantly recovered, and follow-up MRI showed marked regression of bilateral white-matter abnormalities, consistent with reversal of venous hypertensive encephalopathy.
Conclusion: Torcular Herophili DAVFs should be considered in patients presenting with rapidly progressive dementia, parkinsonism, and diffuse white-matter changes, particularly when the clinical course is progressive and conventional investigations are unrevealing. Early recognition of imaging clues followed by digital subtraction angiography is essential for diagnosis. Prompt endovascular embolization can reverse neurological deficits and prevent irreversible brain injury, emphasizing the importance of considering this rare but treatable vascular disorder in the differential diagnosis of rapidly progressive neurological decline.
Keywords: Dural arteriovenous fistula; Venous hypertensive encephalopathy; Torcular Herophili; Parkinsonism; Rapidly progressive dementia; Endovascular embolization.
