Cerebral infarction in the left hemisphere compared with the right hemisphere increases the risk of aspiration pneumonia.

Background: Aspiration pneumonia (AP) following cerebral infarction (CI) has been considered as one of its most serious complications. Nevertheless, there are no reports on the association between the type or location of CI and the incidence of AP. In addition, the association between dysphagia, which leads to aspiration, and the type or location of CI has never been investigated. Therefore we hypothesized that the laterality of CI affects the development of both dysphagia and AP.

Methods: We performed a retrospective cohort study to examine the association between the laterality of CI and the incidence of dysphagia and AP in 133 patients.

Results: AP was found in 6.0% of the group with left CI and in 0.8% of the group with right CI. A univariate logistic regression analysis revealed that left CI was a significant predictor of AP (hazard ratio, 8.81; 95% confidence interval, 1.07-72.59; p = 0.043). Left CI was a significant predictor of AP even after adjusting for age, sex, CI type, or presence of diabetes mellitus. In addition, although the frequency of dysphagia as the direct cause of AP did not differ according to laterality, the frequency of AP that ensued from dysphagia in the left CI group was greater than that observed in the right CI group.

Conclusions: The group with left CI from the motor cortex to the internal capsule complicated by dysphagia exhibited a high risk of AP.