Transverse Sinus Isolated-Type Dural Arteriovenous Fistula Mimicking Ischemic Stroke: A Cautionary Note for Emergency Neurologists; Transvenous Embolization, Fistula Disconnection, and Complete Clinical Recovery

A nonhemorrhagic focal neurological deficit is one of the clinical manifestations of intracranial dural arteriovenous fistulas (DAVF). When symptoms appear suddenly, it is challenging to distinguish DAVF from ischemic stroke in certain circumstances, which might easily lead to misdiagnosis. This case of intracranial DAVF presented with sudden onset sensory dysphasia and hemianopsia, and was initially misdiagnosed as ischemic stroke. Intravenous thrombolysis was planned. A 62-year-old patient presented to the emergency room (ER) with a 3-year history of pulsatile tinnitus and nonspecific transient visual alterations secondary to a suspected DAVF. He had undergone a brain MRI 2 years earlier and refused to further testing and evaluations. He had continued a normal life, working as a senior anesthesiologist at a medical center, and exercised regularly with no other symptoms. He had been admitted to the ER after being found confused and agitated at home, with speech, motor, and visual alterations. Neurological examination revealed sensory dysphasia, right arm paresis, and right hemianopia. Admission cranial CT ruled out hemorrhage, and CT angiography ruled out arterial occlusion. Automated CT-perfusion (CTP) imaging showed a focal perfusion deficit in the left temporal region. The neurology resident was instructed to administer intravenous thrombolysis, but before administering the loading dose, he consulted us regarding the implications of a suspected diagnosis of DAVF in the past. The patient’s admission National Institutes of Health Stroke Scale (NIHSS) score was 14. An ophthalmological exam ruled out papilledema. Urgent MRI-MR angiography (MRA) showed a rich subgaleal and transosseous arterial rete in the left occipital and mastoid regions that drained into the transverse sinus and was proximally thrombosed. It drained through a subtotal thrombosis of the sigmoid sinus and the inferior anastomotic vein of Labbé. Reevaluation of the patient led us to conclude that the risks of thrombolysis outweighed its potential benefits; thus, thrombolytic therapy was not administered. Digital subtraction angiography (DSA) confirmed the diagnosis of isolated left transverse sinus DVAF, nourished primarily by occipital artery branches and drained through cortical veins of the posterior temporal and parietal regions. The DAVF was classed as type III, an aggressive lesion according to Borden-Shucart classifications. We gained access to the isolated transverse sinus pouch by a retrograde transvenous approach via the thrombosed jugular and sigmoid sinus. We proceeded to disconnect the DAVF using coiling and liquid embolic agents. The fistula was completely disconnected, and cortical venous reflux resolved. The patient evolved satisfactorily and experienced a rapid and uneventful complete clinical and neurological recovery, with no residual speech, motor, or visual alterations and complete tinnitus resolution. We present this unusual case of isolated transverse sinus DAVF presenting with stroke-like symptoms that was successfully managed by urgent endovascular embolization, with a surprisingly rapid and complete clinical and neurological recovery.