Early Dynamics of Body Temperature in Acute Stroke: Insights into Outcomes and Management

Background: Following a stroke, body and brain temperatures are closely linked. Elevated temperature may reflect the severity of brain injury rather than infection. The significance of admission temperature remains unclear, and hypothermia treatment lacks proven efficacy and safety. Administering paracetamol (acetaminophen) above 36.5 °C is considered safe, though its clinical benefit is modest. This study aimed to examine how admission temperature, peak temperature in the first 24 h, and temperature fluctuations affect three-month functional outcomes. Methods: We conducted a retrospective study using data from a prospective stroke registry, including 5883 patients (4830 with ischemic stroke [IS] and 1053 with hemorrhagic stroke [HS]). Temperature at admission, maximum temperature within the first 24 h, and the temperature increase during the first day were assessed. Patients with a temperature ≥ 37.5 °C received 3 g of paracetamol per day until normothermia was achieved. Results: Baseline temperature was not associated with 3-month functional outcomes. In IS patients, an increasing temperature during the first 24 h was associated with a 10-fold higher risk of poor functional outcome (sensitivity 81%, specificity 64%); whereas in HS, the risk increased sevenfold (sensitivity 88%, specificity 53%). The most reliable predictor of therapeutic response was the temperature increase on the first day, with sensitivities of 89% and 83%, and specificities of 84% and 71%, for IS and HS, respectively. Conclusions: An increase in temperature during the first 24 h, rather than a single measurement, is the most reliable temperature-based biomarker for predicting poor functional outcomes and guiding the initiation of antihyperthermic treatment.