Physical exertion as a risk factor for perimesencephalic nonaneurysmal subarachnoid hemorrhage

BACKGROUND: Perimesencephalic and nonperimesencephalic nonaneurysmal subarachnoid hemorrhage (PM‐naSAH and NPM‐naSAH) have a different bleeding pattern and clinical course. The etiology and risk factors for PM‐naSAH and NPM‐naSAH are unclear. The objective of this study was to compare risk factors and triggering events between PM‐naSAH and NPM‐naSAH. METHODS: We reviewed retrospectively all patients (n = 3475) who had undergone cerebral digital subtraction angiography between 2003 and 2020 at our tertiary hospital. Of these, 119 patients had 6‐vessel angiography negative subarachnoid hemorrhage (47 (39%) PM‐naSAH and 72 (61%) NPM‐naSAH) and accurate information about the triggering event was available in 42 (89%) PM‐NASAH and 64 (89%) NPM‐naSAH patients. RESULTS: PM‐naSAH were younger compared to NPM‐naSAH (mean age [SD]; 55.3 [11.1] years vs. 59.6 [12.2] years, p = .045. PM‐naSAH was triggered during the physical exertion in 79% of patients and 16% of patients with NPM‐naSAH (relative risk 5.4; 95% CI, 2.9‐10.1, p < .0001). There were no significant difference in sex, smoking, alcohol abuse, hypertension, diabetes, hyperlipidemia, or anticoagulation/antithrombotic usage between PM‐naSAH and NMP‐naSAH, p > .05. CONCLUSION: Physical exertion was a triggering factor in most of the PM‐naSAH cases and the risk was five times greater than in NMP‐naSAH. More studies are needed to confirm our results and to study pathophysiology of PM‐naSAH and NPM‐naSAH.