Mild and moderate strokes usually are not associated with a significant change in body temperature.
In a major stroke the body temperature starts to rise 4-6 hours after the stroke. The higher the rise in temperature the worse the outcome.
The definition of hyperthermia varies in different studies. The temperature cutoff may be > 37°C, >= 37.5°C or > 39°C.
Features of central hyperthermia secondary to direct or indirect brainstem involvement:
(1) rapid onset of high fever (within 12 hours of the stroke)
(2) marked temperature fluctuation
(3) higher maximum temperature
The time of temperature readings relative to stroke onset need to be controlled, especially when considering admission body temperature. Ideally temperature should be monitored soon after stroke onset and periodically thereafter. In addition, the body temperature should be taken in the same manner to reduce methodological variation.
Hypothermia after cerebral injury is considered to be neuroprotective. Ginsberg and Busto suggested that the body temperature should be maintained at 36.7 to 37.0 °C (98.0°F to 98.6°F) for the first few days after the stroke. More recently therapeutic hypothermia is being used in clinical trials to see if it improves outcomes.
