Acquired pial arteriovenous fistula secondary to cerebral cortical vein thrombosis: A case report and review of the literature.

Pial arteriovenous fistulas (AVFs) are rare neurovascular malformations. They differ from arteriovenous malformations (AVMs) in that they involve single or multiple feeding arteries, draining directly into a dilated cortical vein with no intervening nidus. Pial and dural AVFs differ in blood supply, as the first originate from pial or cortical arteries and the latter from outside the dural leaflets. Unlike dural AVFs, most of the pial AVFs are supratentorial. The vast majority are congenital, manifesting during infancy. Acquired pial AVFs are significantly rarer and occur after vasculopathy, head trauma, brain surgery, or cerebral vein thrombosis. We describe a unique case of an acquired pial AVF in a 50-year-old man secondary to a cortical vein thrombosis manifesting as a focal-onset seizure with secondary generalization. A cerebral digital subtraction angiography revealed a low-flow pial AVF fed by a postcentral branch of the left middle cerebral artery draining to the superior sagittal sinus via a cortical vein. It also showed a collateral venous circulation adjacent to the previously thrombosed left parietal vein. There was no evidence of an associated dural AVF or venous varix. Endovascular treatment was scheduled three months later, but the angiogram preceding the embolization showed spontaneous and complete closure of the malformation. To our knowledge, this is the first case illustrating acquired pure pial AVF unaccompanied by a dural component following cortical vein thrombosis, eventually resulting in an unprompted closure.

International alliance and AGREE-ment of 71 clinical practice guidelines on the management of critical care patients with COVID-19: a living systematic review.

OBJECTIVE: We aimed to systematically identify and critically assess the clinical practice guidelines (CPGs) for the management of critically ill patients with COVID-19 with the AGREE II instrument. STUDY DESIGN AND SETTING: We searched Medline, CINAHL, EMBASE, CNKI, CBM, WanFang, and grey literature from November 2019 - November 2020. We did not apply language restrictions. One reviewer independently screened the retrieved titles and abstracts, and a second reviewer confirmed the decisions. Full texts were assessed independently and in duplicate. Disagreements were resolved by consensus. We included any guideline that provided recommendations on the management of critically ill patients with COVID-19. Data extraction was performed independently and in duplicate by two reviewers. We descriptively summarized CPGs characteristics. We assessed the quality with the AGREE II instrument and we summarized relevant therapeutic interventions. RESULTS: We retrieved 3,907 records and 71 CPGs were included. Means (Standard Deviations) of the scores for the 6 domains of the AGREE II instrument were 65%(SD19.56%), 39%(SD19.64%), 27%(SD19.48%), 70%(SD15.74%), 26%(SD18.49%), 42%(SD34.91) for the scope and purpose, stakeholder involvement, rigor of development, clarity of presentation, applicability, editorial independence domains, respectively. Most of the CPGs showed a low overall quality (less than 40%). CONCLUSION: Future CPGs for COVID-19 need to rely, for their development, on standard evidence-based methods and tools.