Two first-degree relatives with perimesencephalic nonaneurysmal hemorrhage

Abstract

Perimesencephalic (or pretruncal) nonaneurysmal hemorrhage (PMH) constitutes about 10% of all episodes of subarachnoid hemorrhage (SAH). The estimated incidence of the disease is 0.6 per 100,000 persons per year.1 PMH, first described in 1985, is characterized by accumulation of subarachnoidal blood predominantly within the prepontine cistern and absence of aneurysm or other bleeding source on angiography.2 Contrary to aneurysmal SAH, the clinical course of PMH is usually uneventful, not complicated by rebleeding or delayed cerebral ischemia, and the outcome of PMH is excellent.1 Studies evaluating the risk of first- and second-degree relatives of patients with SAH focus on aneurysmal SAH, showing a positive family history in 7 to 20% in case-control series.3 Although the exact etiology of PMH is still unclear, it is clinically and pathophysiologically distinct from aneurysmal SAH. Familial predisposition or genetic susceptibility factors are not known. We present two first-degree relatives with PMH, suggesting a …