Do acute phase markers explain body temperature and brain temperature after ischemic stroke?

OBJECTIVE

Both brain and body temperature rise after stroke but the cause of each is uncertain. We investigated the relationship between circulating markers of inflammation with brain and body temperature after stroke.

METHODS

We recruited patients with acute ischemic stroke and measured brain temperature at hospital admission and 5 days after stroke with multivoxel magnetic resonance spectroscopic imaging in normal brain and the acute ischemic lesion (defined by diffusion-weighted imaging [DWI]). We measured body temperature with digital aural thermometers 4-hourly and drew blood daily to measure interleukin-6, C-reactive protein, and fibrinogen, for 5 days after stroke.

RESULTS

In 44 stroke patients, the mean temperature in DWI-ischemic brain soon after admission was 38.4° C (95% confidence interval [CI] 38.2-38.6), in DWI-normal brain was 37.7° C (95% CI 37.6-37.7), and mean body temperature was 36.6° C (95% CI 36.3-37.0). Higher mean levels of interleukin-6, C-reactive protein, and fibrinogen were associated with higher temperature in DWI-normal brain at admission and 5 days, and higher overall mean body temperature, but only with higher temperature in DWI-ischemic brain on admission.

CONCLUSIONS

Systemic inflammation after stroke is associated with elevated temperature in normal brain and the body but not with later ischemic brain temperature. Elevated brain temperature is a potential mechanism for the poorer outcome observed in stroke patients with higher levels of circulating inflammatory markers.