Background: Studies on the effect of body temperature on outcome in stroke are conflicting with most demonstrating that elevated body temperature is associated with poor outcome in stroke, and some indicating that very early body temperature elevation is associated with better outcomes. We sought to characterize the relationship of body temperature and clinical deterioration by evaluating serial measurements over 24 hours.
Methods: All subjects were enrolled <2 hours after stroke symptom onset into the Phase 3 NIH Field Administration of Stroke Therapy Magnesium (FAST-MAG) clinical trial testing magnesium for prehospital neuroprotection. Presenting temperature in the emergency room and follow-up temperatures at 8, 16 and 24 hours after arrival were recorded. Acute deterioration was defined as 4 point worsening on NIHSS from presentation to 24 hours. Mean temperature was compared at all time points for deteriorators and non-deteriorators utilizing t-test. All measures were in °C.
Results: Of 1700 subjects 1586 (93%) had temperature recorded on ED arrival, 1594 at 8 hours, 1611 at 16 hours, and 1594 at 24 hours (1385 had all 4 recorded). Mean age was 69 years, 43% were women, final diagnosis cerebral ischemia in 73.3%, intracranial hemorrhage in 22.8%, and mimic in 3.9%. Mean body temperature for deteriorators was not different at presentation (36.5 vs. 36.6, p=0.221), but was significantly higher at 8 hours (36.8 vs. 36.6, p<0.001), at 16 hours (37.0 vs. 36.7, p<0.001) and 24 hours (37.0 vs. 36.7, p<0.001). Of cerebral ischemia cases (N=1150) the same temperature relationship held true (presentation: 36.6 vs. 36.6, p=0.744, 8-hours: 36.7 vs. 36.6 p=0.002, 16 hours: 36.8 vs 36.6 p<0.001, 24 hours: 36.9 vs. 36.7, p<0.001). In cases of ICH elevated temperature was not significantly higher until 16 hours after arrival (presentation: 36.5 vs. 36.6, p=0.173, 8-hour: 36.9 vs. 36.8 p=0.313, 16 hour: 37.2 vs. 36.9 p<0.001, 24-hour: 37.1 vs 36.9 p=0.036).
Conclusions: Higher body temperatures were noted in those experiencing clinical deterioration 8 hours after arrival. Early elevations in body temperature may be a predictor of clinical deterioration in acute stroke.