Perimesencephalic Nonaneurysmal Subarachnoid Hemorrhage Caused by Physical Exertion

Abstract

The clinical characteristics of perimesencephalic nonaneurysmal subarachnoid hemorrhage (SAH) caused by physical exertion were analyzed to investigate the causes and mechanisms of perimesencephalic nonaneurysmal SAH. Nine of 209 patients with spontaneous SAH were identified as having perimesencephalic nonaneurysmal SAH. Perimesencephalic nonaneurysmal SAH in four males and three females was precipitated by exertion. Age, sex predominance, type of exertion, symptoms, loss of consciousness during bleeding, clinical grade, angiographic spasm, hydrocephalus, delayed ischemic deficit, rebleeding, hypertension, and outcome were evaluated in these seven patients. Outcomes were assessed using the Glasgow Outcome Scale. Patients showed male predominance (57.1%), relatively young age (mean 50 years), low frequency of hypertension (28.6%), good clinical grade (World Federation of Neurological Surgeons grade I or II), and excellent outcomes including no rebleeding, no symptomatic hydrocephalus, and no delayed ischemic deficits. The type of exertion was swimming in two patients, golfing in two patients, heavy lifting in two patients, and bending forward during gymnastics in one patient. Physical exertion including components of the Valsalva maneuver is an important predisposing factor for perimesencephalic nonaneurysmal SAH. Such physical exertion produces increased intrathoracic pressure, which blocks the internal jugular venous return, resulting in elevated intracranial venous pressure or mechanical swelling of the intracranial veins, and leads to venous or capillary breakdown.

Clinical course of nontraumatic nonaneurysmal subarachnoid hemorrhage: a single institution experience over 10 years and review of the contemporary literature

“…Patients with NNSAH tend to be male, younger and less hypertensive compared with those with aneurysmal SAH according to the current literature (6,13,23,42,52). The agerelated epidemiological data of our study cohort was in line with that of existing literature (mean age of 51 years); however, our study found no gender predominancy (51% to 49%).…”

Clinical relevance of negative initial angiogram in spontaneous subarachnoid hemorrhage

“…Possible sources include occult aneurysm, vascular malformation, intracranial arterial dissection, and cerebral venous thrombosis. 23,[27][28][29] Because of the high predictive value of the hemorrhage pattern on CT and the benign nature of perimesencephalic SAH, some authors advocate the need for only a single angiogram in those cases. 30 However, repeat angiography is almost always indicated in cases of non-perimesencephalic angiogram-negative SAH, because structural abnormalities such as aneurysms can be obscured on the first angiogram, which occurs in 4-30% of cases.…”

An Analysis of 88 Patients with Diffuse and “Benign” Perimesencephalic Subarachnoid Hemorrhage

“…[2][3][4][5] Although aneurysmal SAH is characterized by an aneurysmal source of SAH demonstrated on imaging, angiogram-negative SAH is characterized by an initial negative imaging work-up for aneurysmal source and may be associated with a wide variety of lesions including arteriovenous malformation (AVM), spinal AVM, venous anomaly, and so on. 4,[6][7][8][9][10][11][12][13][14][15] Perimesencephalic spontaneous subarachnoid hemorrhage (PMSAH) was originally characterized based on computed tomography (CT) SAH patterns that contained extravasated blood within the basal cisterns and around the midbrain, including a variant with blood only in the quadrigeminal cistern 16 and no identifiable source demonstrated on angiography. 17 PMSAH has been shown to represent approximately two-thirds of all cases of angiogramnegative spontaneous SAH.…”