Body Temperature in Acute Stroke
To the Editor:
I read with great interest the recent article by Boysen and Christensen1 on body temperature. Their study is probably the first to have described the hourly changes in body temperature after onset of stroke and intracerebral hemorrhage. Although they used paracetamol for the patient with a body temperature >37°C, the pattern was very similar to that observed in an animal experiment.2 This suggests that the basic mechanisms underlying the temperature changes after cerebral stroke are the same in both animals (rats) and humans. However, I have one very serious question. The authors measured body temperature at the tympanic membrane but did not show the normal value of the body temperature measured by this method. They administered paracetamol to reduce body temperature when the temperature exceeded 37.0°C. However, several studies have documented that the normal body temperature measured at the tympanic membrane is 37.5°C.3,4⇓ This means that, in fact, the initial body temperature after cerebrovascular disorders reported by them (36.5°C) may have been lower than normal (ie, hypothermic). Therefore, I think that the true explanation of their result is that cerebral ischemia or intracerebral hemorrhage can lower body temperature, at least for the first few hours after onset.
- ↵Boysen G, Christensen H. Stroke severity determines body temperature in acute stroke. Stroke. 2001; 32: 413–417.
- ↵Li F, Omae T, Fisher M. Spontaneous hyperthermia and its mechanism in the intraluminal suture middle cerebral artery occlusion model of rats. Stroke. 1999; 30: 2464–2471.
- ↵Yoshiue S, Yoshizawa H, Ito H, Nagashima K, Takeda K, Yazumi T, Takeuchi H, Nakamura N, Nagae M, Ogata J, Ishida M, Kawashima Y, Uchino K. Body temperature [in Japanese]. Sohgo Rinsho. 1985; 34: 1599–1606.
We thank Dr Takagi for his interest in our study on body temperature in acute stroke. In our study, temperature was measured by a tympanic thermometer, FirstTemp Genius 3000 A. Dr Takagi suggests that normal body temperature at the tympanic membrane is 37.5°C, and that our patients were hypothermic initially.
We recently compared rectal temperature measured by mercury thermometer and temperature measured by the tympanic device in 95 stroke patients.1 The mean temperature by rectal temperature measurements was 37.16°C (range, 36.2°C to 38.1°C). The mean temperature by the tympanic measurement was 37.12°C (range, 35.5°C to 38.3°C). We thus could not confirm that the investigated tympanic device results in higher temperatures than the rectal measurements. However, we found that tympanic temperatures varied more than the rectal temperatures.
We agree that in the cited article,2 initial temperature in our acute stroke patients was slightly below normal, especially in those with severe stroke. The rise in temperature over the first 10 to 12 hours was restricted to patients with severe strokes.