Case of the Month
Section Editor: Nicholas Stence, MD
Children's Hospital Colorado, Aurora, CO
November 2013
Next Case of the Month coming December 3 . . .
Dural Arteriovenous Fistula
- DAVFs account for 15% of cerebrovascular malformations. Typically develop in the region of the transverse and sigmoid sinuses, although they may affect the dura in any part of the CNS. Lesions arise as secondary to increased pressure within the dural sinuses, possibly as a sequela of sinus thrombosis.
- In some cases, increased pressure develops within the venous sinus, and the flow increase through the DAVF causes retrograde transmission of pressure leading to enlargement of cortical veins and impairment of parenchymal venous drainage. As a result, cerebral parenchyma changes occur, including focal areas of gliosis, vasogenic edema, and petechial hemorrhage.
- Symptoms, prognosis, and management are related to type of venous drainage (dural sinus or cortical venous drainage) and direction of flow (Borden classification, type I-III; Cognard classification, type I-V).
- DSA is the gold standard for the diagnosis and classification of DAVFs, and provides a route for endovascular treatment.
- Clinical Presentation: Most patients present in the 5th to 6th decades of life. Symptoms variable, and are related to the location of the lesion and pattern of venous drainage.
- Key Diagnostic Features: Noncontrast CT: Intracranial hemorrhage and edema due to venous congestion. MR: Dilated vessels, venous pouches, vascular enhancement with no true nidus within the brain parenchyma, and signs of venous hypertension. CTA, MRA, or DSA: Early venous filling, contribution from ECA branches, and shunt location.
- DDx: Glial tumors, hemorrhagic infarct, metabolic encephalopathy
- Rx: Definitive treatment requires occlusion of the AV shunt. Currently, the first treatment option is endovascular embolization, with open neurosurgery as a second option. Small percent, radiosurgery.
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