Triggering factors in non-traumatic intracerebral hemorrhage.

Background: In ischemic stroke and subarachnoid hemorrhage, there are known preceding triggering events that predispose to the stroke by, for example, abruptly raising blood pressure. We explored, whether triggering events can be identified in non-traumatic intracerebral hemorrhage (ICH).

Methods: We used structured questionnaires to interview consented patients with ICH treated in a tertiary teaching hospital, between 2014 and 2016. We asked of possible trigger factors, including Valsalva-inducing activity, heavy physical exertion, sexual activity, abrupt change in position, a heavy meal, a sudden change in temperature, exposure to traffic jam, and the combination of the first three (any physical trigger) during the hazard period of 0-2 h prior to ICH. The ratio of the reported trigger during the hazard period was compared to the same 2-h period the previous day (control period) to calculate the relative risks for each factor (case-crossover design).

Results: Of our 216 consented ICH patients, 97 (35.0%) could be interviewed for trigger questions. Reasons for not able to provide consistent and reliable responses included lowered level of consciousness, delirium, impaired memory, and aphasia. None of the studied possible triggers alone were more frequent during the hazard period compared to the control period. However, when all physical triggers were combined, we found an association with the triggering event and onset of ICH (risk ratio 1.32, 95% confidence interval 1.01-1.73).

Conclusions: Obtaining reliable information on the preceding events before ICH onset was challenging. However, we found that physical triggers as a group were associated with the onset of ICH.