Temporal profile of body temperature in acute ischemic stroke: relation to stroke severity and outcome

Abstract

BackgroundPyrexia after stroke (temperature ≥37.5°C) is associated with poor prognosis, but information on timing of body temperature changes and relationship to stroke severity and subtypes varies.MethodsWe recruited patients with acute ischemic stroke, measured stroke severity, stroke subtype and recorded four-hourly tympanic (body) temperature readings from admission to 120 hours after stroke. We sought causes of pyrexia and measured functional outcome at 90 days. We systematically summarised all relevant previous studies.ResultsAmongst 44 patients (21 males, mean age 72 years SD 11) with median National Institute of Health Stroke Score (NIHSS) 7 (range 0–28), 14 had total anterior circulation strokes (TACS). On admission all patients, both TACS and non-TACS, were normothermic (median 36.3°C vs 36.5°C, p=0.382 respectively) at median 4 hours (interquartile range, IQR, 2–8) after stroke; admission temperature and NIHSS were not associated (r2=0.0, p=0.353). Peak temperature, occurring at 35.5 (IQR 19.0 to 53.8) hours after stroke, was higher in TACS (37.7°C) than non-TACS (37.1°C, p<0.001) and was associated with admission NIHSS (r2=0.20, p=0.002). Poor outcome (modified Rankin Scale ≥3) at 90 days was associated with higher admission (36.6°C vs. 36.2°C p=0.031) and peak (37.4°C vs. 37.0°C, p=0.016) temperatures. Sixteen (36%) patients became pyrexial, in seven (44%) of whom we found no cause other than the stroke.ConclusionsNormothermia is usual within the first 4 hours of stroke. Peak temperature occurs at 1.5 to 2 days after stroke, and is related to stroke severity/subtype and more closely associated with poor outcome than admission temperature. Temperature-outcome associations after stroke are complex, but normothermia on admission should not preclude randomisation of patients into trials of therapeutic hypothermia.

Reduction of the systemic inflammatory induced by acute cerebral infarction through ultra-early thrombolytic therapy

“…Other studies have indicated that it is not admissional body temperature that is associated with adverse outcomes of stroke, but the temperature peak occurring a few days after the stroke (18)(19)(20). The present study revealed that the more serious the stroke and the higher the NIHSS score, the more the body temperature increased.…”

Temporal profile of body temperature in acute ischemic stroke: relation to infarct size and outcome

“…However, no source of infection could be found in almost half of the hyperthermic patients in a previous study [8]. Fever could also be the result of an inflammatory response of the body to the infarcted tissue.…”

“…Several studies have suggested that this is limited to body temperatures on admission or during the first day, [3, 5, 6, 10, 11, 13] whereas others have found that this relation persists for up to one week [2, 7–9, 12]. These inconsistencies may be attributed to differences in study designs and populations, [8] for example related to the time of admission, [13] the definition of a poor outcome outcome, [11] and selection of patient populations [3, 10]. …”

Initial Body Temperature in Ischemic Stroke

“…BT has been reported to arise 4 to 6 hours after stroke onset through a systemic response to brain insult and this elevation reaches a peak between 1 and 2 days after stroke. 2, 4, 30 Accordingly, BT measured in the subacute period, 4-48 hours after onset are likely to be directly related to stroke severity, while BTs measured in the acute period, within the first 4 hours, appear to be inversely related to stroke severity.…”

“…1-4 However, in the hyperacute stage, during the first 1-6 hours after onset, studies have not uniformly supported an association of presenting hyperthermia with increased severity. 1-10 Indeed, a few studies have suggested a reverse relationship: increased initial BT associated with less severe neurologic deficits and more neurologic improvement within 24 hours.…”