Background: Spleen volume reduction followed by a re-expansion has been described in acute ischemic stroke in both animal and human studies. Splenic contraction might be partially due to sympathetic hyperactivity and might be accompanied by a release of splenocytes in the peripheral circulation, leading to immunodepression. 

Aims: To investigate whether spleen volume changes in the first week after stroke are associated with post-stroke infections, changes in lymphocytes count, autonomic dysfunction and poor functional outcome. 

Methods: In 32 patients with acute ischemic stroke, spleen sizes were calculated from abdominal CT images on day one and day seven. Spleen size reduction was defined as > 10 % spleen size reduction between day one and day seven. We assessed the time course of leukocyte subsets and analysed pulse rate variability (PRV) indices.  Post stroke infections were diagnosed during the first seven days after stroke onset using the modified criteria of the US Centers of Disease Control and Prevention. Early neurological deterioration was defined as an increase in National Institute of Health Stroke Score (NIHSS) by two or more points or stroke related death between admission and day three. Poor functional outcome was defined as a modified Rankin Scale score of > two at three months.

Results: Post-stroke infections occurred in six out of 11 patients with spleen size reduction versus in three out of 21 patients without spleen size reduction (p=0,035). Spleen size reduction was associated with a drop in lymphocyte and several lymphocyte subsets from admission to day two and with higher NIHSS at day three (p=0,020). No correlations could be found between spleen volume change and PRV parameters. 

Conclusion: These results suggest an association between post-stroke infections and spleen volume reduction in acute ischemic stroke.

POST-STROKE INFECTIONS ASSOCIATED WITH SPLEEN VOLUME REDUCTION