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Título

INTRACRANIAL DURAL ARTERIOVENOUS FISTULA: CASE REPORT

RESUMO

Case presentation: Male patient, 40 years old, admitted with a headache for 1 week, progressive, weighty, holocranial, associated with bilateral pulsatile tinnitus, without suggestive ICH. He progressed to a generalized tonic-clonic seizure with sphincter release followed by loss of consciousness in July/2021. He was diagnosed with SAH in the frontal and right temporal regions by CT and CTA, and failure to fill the sagittal venous sinus after contrast administration. He denied any comorbidities or medication use. Referred to ICU with no return of consciousness. A cranial CT was redone one week later revealing the resolution of SAH. Arteriography was indicated to search for an aneurysm, however, due to lack of clinical control, the patient was not submitted. The patient improved and was discharged. A hematologist diagnosed thrombosis and indicated anticoagulant therapy (dabigatran 150mg). After treatment, partial recanalization of the superior sagittal sinus was presented by CTA with thrombosis resolution and an improvement of headache, but with tinnitus maintenance. The differential diagnosis was cerebral venous thrombosis or intracranial dural arteriovenous fistula (IDAF). New arteriography revealed the presence of IDAF in the torcula and left transverse/sigmoid venous sinuses, Cognard grade 1, with an absence of venous reflux; coupled with partial venous thrombosis of the superior sagittal and left transverse/sigmoid sinuses. Discussion: IDAFs represent 15% of intracranial vascular malformations, frequently occurring between 50-60 (age). They may present in a diverse symptomatic manner, ranging from less aggressive manifestations (e.g., headache and tinnitus) to more aggressive ones (e.g., progressive cognitive decline) determined by the venous drainage pattern and the location of the fistula. These fistulas mainly occur in the cavernous, transverse, and sigmoid sinuses, and the cerebral tent. The main way of classifying IDAFs is according to Cognard types I and IIa (benign) and IIb, IIa + b, III, IV and V (malignant). The benign ones drain directly into the venous sinuses, while the malignant ones have direct or indirect reflux into the cortical veins. CT, CTA, and MRI are the first-line diagnostic tools, but DSA has established itself as the gold standard for a suspected IDAF. Final comments: The established relationship between IDAF with thrombosis and the possibility of hemorrhagic transformation therefrom obscures the cause-consequence relationship.