Perimesencephalic nonaneurysmal subarachnoid haemorrhage and variations in the veins

Abstract

Perimesencephalic nonaneurysmal subarachnoid haemorrhage (PN-SAH) is characterised by accumulation of blood around the midbrain, normal angiographic findings and an excellent prognosis. The etiology of PN-SAH has not yet been determined. Therefore we decided to compare the venograms of patients with PN-SAH with those of patients with aneurysmal SAH (A-SAH) in order to examine the relationship between PN-SAH and venous structures. We retrospectively studied 6 patients with PN-SAH and 102 cases of angiographically evaluated A-SAH during the past 12 years by reviewing their venograms for possible abnormalities in venous structures, particularly in the basal vein of Rosenthal (BVR). More abnormalities in venous structures were found in the patients with PN-SAH than in those with A-SAH. Most of the BVR in the patients with PN-SAH appeared to drain into various dural sinuses instead of the galenic system. The relationship between PN-SAH and abnormalities in venous structures was determined.

Venous Drainage in Perimesencephalic Hemorrhage

“…In all 6 patients with PMH, the basal vein of Rosenthal drained into various dural sinuses rather than in the Galenic system (type C primitive variant) on 1 or both sides. 11 Similar primitive forms of the venous system were less frequently found in patients with aneurysmal SAH. In our study with a larger series of patients and with the entire data set available for review, many, but not all, patients with a PMH had a primitive drainage.…”

“…11 The basal vein of Rosenthal is a secondary vessel formed by longitudinal anastomosis of three primitive veins. These primitive veins drain initially into the tentorial sinuses; however, during development, these draining veins generally obliterate and drainage becomes mainly into the Galenic system.…”

“…Venous drainage was classified according to Watanabe et al: 11 in normal continuous (type A), the basal vein of Rosenthal is continuous with the deep middle cerebral vein and drains mainly to the vein of Galen; in normal discontinuous (type B, common variant), there is discontinuous venous drainage, anterior to uncal vein and posterior to vein of Galen; and in the primitive variant (type C), there is drainage mainly to veins other than vein of Galen (perimesencephalic veins draining to the superior petrosal sinus or basal vein of Rosenthal draining directly to the transverse or straight sinus). The Additionally, we assessed on noncontrast CT (NCCT) scans of PMH patients if the pattern of hemorrhage was symmetrical or asymmetrical.…”

Idiopathic subarachnoid hemorrhage: a multicentre series of 220 patients

“…The pmISAH type has been a matter of multiple reports in the literature 50,61,62,69,70 , but many questions are still unsolved, as the origin of the SAH itself from an arterial 37,42,47,59,74 , or a venous source 15,36,41,43,58,70 . There is also an interesting debate about the possible relation between pmISAH and some profound venous system variants or anomalies 3,13,68,73,77 . Controversy also affects the decision of how many radiological examinations should be performed in pmISAH cases to rule out the possibility of false negative angiogram for posterior circulation aneurysm 2,69,71,76 .…”

Perimesencephalic Non-aneurysmal Subarachnoid Hemorrhage Caused by Cavernous Sinus Thrombosis-Case Report-

“…Patients with perimesencephalic non-aneurysmal SAH are more likely to have primitive venous drainage directly into the dural sinuses instead of via the vein of Galen than normal subjects, 7) but otherwise angiography shows no abnormalities. 8) Cavernous sinus thrombosis is a vascular accident that causes proptosis and eye movement disorders, and is one of the many causes of painful ophthalmoplegia, which occurs in association with distant or general infections. 5) Cavernous sinus thrombosis has never been reported as a cause of SAH and no association between sinus thrombosis and SAH has been confirmed.…”