Nonaneurysmal Perimesencephalic Subarachnoid Hemorrhage: Diagnosis, Pathophysiology, Clinical Characteristics, and Long-Term Outcome

Cerebral vasospasm and delayed cerebral infarctions in 225 patients with non-aneurysmal subarachnoid hemorrhage: the underestimated risk of Fisher 3 blood distribution

“…In the current series, patients with NPM-SAH or PM-SAH had a different outcome. Patients with PM-SAH had an excellent outcome, as in other series,7 8 15 16 21 24–26 which also confirmed that the patients were classified correctly. However, excluding Fi3 (favorable outcome in only 71% of the patients; table 1), patients with NASAH without Fi3 also had an excellent chance of a favorable outcome, similar to patients with PM-SAH (both about 90%; table 2).…”

“…Data from series with small patient numbers showed a similar outcome between perimesencephalic (PM) and non-PM (NPM) SAH but larger series, maybe due to the improved statistical power, identified different outcomes between PM-SAH and NPM-SAH 6 7. In a recent review of PM-SAH, most series had a patient cohort of about 50 patients and only one paper had a cohort of more than 150 patients 8. However, in patients with NASAH, cerebral vasospasm (CVS) can occur, requiring endovascular vasospasm treatment,9 and the rate of patients with long-lasting CVS was similar to aneurysmal SAH 10…”

Management of Spontaneous Subarachnoid Hemorrhage Patients with Negative Initial Digital Subtraction Angiogram Findings: Conservative or Aggressive?

“…Hydrocephalus is one of the most common complications of NASAH, normally identified by symptoms of elevated intracranial pressure (progressive headache, altered sensorium) or findings on head CT [36]. The incidence of hydrocephalus from the present cohort was 14.3%, which is in agreement with previous reports [34]. We also found that, in the nonperimesencephalic pattern, the presence of intraventricular hemorrhage or poorer clinical grade on presentation (GCS < 13 and modified Fisher Scale > 2) were associated with the development of hydrocephalus.…”

“…It is wildly accepted that NASAH patients have a more favorable clinical course and a lower incidence of complications when compared to those with aSAH [34]. The subgroup of PMN-SAH was first described by van Gijn et al [35] as a benign entity, characterized by the distribution of the subarachnoid hemorrhage mainly or only in the perimesencephalic cisterns.…”

Sexual activity as a trigger for intracranial hemorrhage

“…While venous anomalies are theorized as the source of SAH, the etiology of these hemorrhages is not known [19]. However, evidence suggests that non-aneurysmal perimesecephalic hemorrhages are more commonly associated with straining at the time of Only illicit drug use and the use of antithrombotics and/or phosphodiesterase-5 inhibitors are reported ictus than aneurysmal SAH [3,19,44], potentially explaining its occurrence during sexual activity. The Valsalva maneuver has been implicated as a trigger for aneurysm rupture [38], non-aneurysmal perimesencephalic hemorrhage [44], and venous cerebral hemorrhage [2].…”