Parkinsonism and urinary incontinence are rare manifestations of DAVF which may lead to misdiagnosis and they have been seldom reported(12). Our study demonstrates a potential relationship between DAVF and parkinsonism as well as urinary incontinence. The following pathophysiological mechanisms are considered to cause parkinsonism in the present case of DAVF. The arteriovenous fistulous developed between the arterial fistula (bilateral occipital and superficial temporal arteries) and the SSS cause a significant arterial steal, which can induce ischemia in frontal, temporal lobes and basal ganglia. And chronic arterial ischemic changes subsequently result in diffuse white matter hyperintensities and basal ganglia damages, ultimately triggering parkinsonism(13). Although the imaging manifestation of white matter hyperintensities in this case seems similar to that of vascular parkinsonism(14), it is reversible as we described, which cannot be completely explained by chronic arterial ischemia. Similarly, the reversible white matter lesion (WML) can also be observed in SSS region in DAVF presenting with dementia(15). However, there are currently no specific cases of reversible WML in SSS region in DAVF presenting with parkinsonism. Both dementia and parkinsonism secondary to DAVF selectively affect the deep white matter rather than the cortex or the basal ganglia. Thus, venous congestion is more likely to be considered as the mechanism underlying the parkinsonism in DAVF of this case as previously reported(16, 17). Venous congestion leads to relative outflow obstruction, which may cause the hypoperfusion. Subsequently, the patient suffered from progressive urinary incontinence that is even more rare in intracranial DAVF with only approximate five cases reported(12), and the mechanism has not been clearly elaborated. These atypical clinical manifestations of the patient easily lead to misdiagnosis, so neurologists need to keep the reversible etiology in mind. Besides, both symptoms and manifestations in re-examined MRI and MRV of this patient significantly improved one year after the surgical treatment. Therefore, it is probable that earlier treatment for DAVF could have avoided the Parkinsonism and urinary incontinence.
DAVF possesses significant geographic variations with different causes. Most DAVF in the United States and Europe is located in the sigmoid and transverse sinuses, while in Asia it’s commonly located in the cavernous sinus(18). Involvement of SSS region in DAVF is rarely seen(19), which mostly has bilateral feeding arteries from the branches of unilateral or bilateral middle meningeal artery (MMA)(20). The scalp arteries can also be concerned in DAVF involving SSS region(21). In addition, OA and STA have also been rarely reported as the feeding arteries, especially the bilateral OAs or STAs(22). The OA is usually involved in the post-portion of SSS region in DAVF while the STA is involved in the midportion of SSS region. The patient in our study suffered from multiple DAVF involving the SSS regions that are relatively symmetrically distributed. Bilateral OAs or STAs, as the feeding arteries, are rarely reported. Additionally, the scalp arteries are also be involved in the SSS region in DAVF. Currently, sinus thrombosis, trauma, inflammation, and iatrogenic injury are also considered as usual causes(23). In this case, the patient had a 25-year history of trauma on head, which may be the trigger of DAVF’s formation. Furthermore, most DAVF involving the SSS region are deemed to demand surgical treatment and endovascular treatment (EVT) is considered as the most optimal therapy.