Hypothermia and the assessment of sick children
25 June 2013
The new NICE clinical guideline (2013), Feverish Illness in Children(1) focuses on best practice advice for febrile children under the age of five years. It is gratifying to see that the guidelines include updated recommendations on thermometry, measurement sites, and clinical assessment together with a section on life-threatening features of illness in children; fever being one of a number of signs. On this note, we may offer a word of caution to re-dress the balance for concern about altered thermoregulation in sick children. Fever per se is a cardinal sign of inflammation, infection and trauma. At the other end of the scale, low body temperature is also a manifestation of disordered thermoregulation.
Whilst the NICE guideline is focused on febrile illness there is a clear message, interwoven within the text sub-headings, of the value of different levels of fever in the assessment of risk of serious illness, particularly so for infants below the age of three months. On the spectrum of thermoregulatory disturbance associated with disease and life-threatening illness, it is possible in clinical practice to observe the gamut of change in human core body temperature; temperature commensurate with high fever as well as below 'normal' temperature.
Within the sepsis continuum, below normal body temperature is most likely to occur in severe sepsis and septic shock(2,3). Hypothermia in sepsis developed in 9% of septic patients and mortality was significantly higher (62%) versus 26% for septic non-hypothermic patients(4).
The NICE guidelines refer to one side only of human thermoregulatory disturbances. An unresolved question regarding the guidance is in understanding its remit; are the guidelines primarily about detection of feverish illness in children or in assisting healthcare professionals in the identification of serious childhood illness? If it is the latter, low temperature must be recognised and included in the signs and assessment of serious childhood illness.
A recent (unpublished) audit of body temperature readings in 23,954 children admitted to the Emergency Department (Sheffield Children’s NHS Foundation Trust) showed that 21% presented with temperature in excess of 37.6°C but 12% of children had a temperature of less than 36.0°C, measured using an electronic axillary or tympanic thermometer depending on the child’s age. Hypothermia is considered to be 36.0°C or below in other NICE Guidance(5). Therefore, below 'normal' body temperatures are not uncommon.
Outside of the field of neurosurgery (where hypothermia is frequently induced deliberately) concerns in clinical medicine are weighted rather more towards harm due to raised temperature than to low temperature(6).
Whilst there are certainly issues to consider around the accuracy of body temperature measurement, addressed well in the NICE guidelines, the incidence of ‘true’ illness-associated low body temperature is undetermined. The lack of standard use clinical thermometers that read accurately below 35.5°C means we have a poor epidemiological understanding of lower than normal body temperatures. We would urge the inclusion of low, as well as raised body temperature, in the assessment of serious illness in children for future epidemiological study.
1. NICE (2013). Feverish illness in children - Assessment and initial management in children younger than 5 years http://www.nice.org.uk/nicemedia/live/14171/63908/63908.pdf Accessed 29.5.13
2. Hofer N, Müller W, Resch B. (2012) Neonates presenting with temperature symptoms: role in the diagnosis of early onset sepsis. Pediatrics International. 54(4):486-90.
3. Milner D, Wailoo M, Swift P, Fraser M (2003) Prolonged hypothermia following respiratory syncytial viral infection in infancy Archives of Diseases of Childhood 88:69-70
4. Remick, Daniel G., and Hongyan Xioa (2006). Hypothermia and sepsis. Frontiers in Bioscience 11:1006-1013.
5. NICE (2008) Inadvertent perioperative hypothermia - Quick reference guide http://www.nice.org.uk/nicemedia/live/11962/40396/40396.pdf (accessed 20.6.13)
6. Blumenthal I (1998) What parents think of fever Family Practice 15(6): 513-8
Competing interests: None declared
Sheffield Hallam University, Centre for Health and Social Care Research (CHSCR), Collegiate Crescent, Sheffield , S10 2BP
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