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Three Part Question

In [an elderly patient] does [a temperature of 37.5C] diagnose [fever]?

Clinical Scenario

You are working in the Emergency department and are asked to see an 80 year old lady who has been brought in by ambulance. Her problems appear to be mainly social, however you notice that her temperature is 37.5C and you wonder whether this is significant enough to suspect a pyrexial illness.

Search Strategy

OVID interface on the world wide web. 1966 – 05/04
{[exp body temperature OR body temperature.mp] AND [exp reference values OR reference values.mp OR normal.mp] AND [exp aged OR elderly.mp] LIMIT to human AND english}

Search Outcome

Altogether 482 papers were found of which 3 were relevant.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Darowski A, Weinberg JR and Guz A 1991 UK	Hospital inpatients aged 70 or over in ambiant temeratures of 21 to 26 C Exclusion criteria - Clinical suspicion of infection or other febrile illness. COPD, previous UTI, urinary catheter, if blood or sputum cultures sent, urine positive culture/microscopy, high neutrophil count.	Survey	Rectal, axillary, auditory canal and sublingual temeratures were measured simultaneously. Different thermometers were used depending on the site.	Rectal temperature mean 37.2C +/-2SD 36.8-37.6 Auditory temerature mean 36.8C +/-2SD 36.5 - 37.1 Sublingual temperature mean 36.6C +/-2sd 36.1-37.2 Axillary temperature mean 36.3C +/-2SD 35.5-37.0	Convenience sample. Exclusion criteria could exclude people with higher temperatures which were non pathological.
Howell TH 1975 UK	105 female convalescent patients aged from 61 to 100 Exclusions - ???	Survey	Temperature taken with an electronic oral thermometer	Temperature range 30.0 to 37.2C	Very limited method and results sections. No indication how subjects chosen or exclusion criteria.
Chamberlain JM et al 1995 USA	2,447 subjects aged from 12 hours to 103 years Exclusions - Anti pyretic medication within 24hrs, fever or illness associated with fever in the last 48 hours	Survey	Temerature measured with an infrared thermometer from the tympanic membrane.	Age 16-65 mean 36.55C (SD 0.44) 99th percentile 37.58C Age 66-75 mean 36.46C (SD 0.43) 99th percentile 37.46C Age 76-85 mean 36.43C (SD 0.48) 99th percentile 37.55C Age >85 mean 36.40C (SD 0.46) 99th percentile 37.47C	Convenience sample. Exclusion criteria could exclude people with higher temperatures which were non pathological.

Comment(s)

Temperature has been used as a diagnostic tool for >150 years. Consequently the greater quantity of research has been performed prior to the past 28 years. These studies may be using exclusion criteria which are surrogates for temperatue (clinical suspicion of febrile illness - exclude patients who feel hot) and consequently finding a range of reading which are innapropriately low. In the absence of other data the studies quoted provide a useful starting point for interpreting temperature in the elderly.

Clinical Bottom Line

A temperature of 37.5C is outside the normal range for an elderly patient. Suspicion should be raised for condition associated with pyrexia.

References

1. Darowski A, Weinberg JR and Guz A Normal Rectal,Auditory Canal, Sublingual and Axillary Temperatures in Elderly Afebrile Patients in a Warm Environment Age and Ageing 1991;20:113-119
2. Howell TH Oral Temperature range in old age. Geront, clin, 17: 1975 133-136
3. Chamberlain JM et al Determination of Normal Ear Temperature with an Infrared Emission Detection Thermometer Annals of Emergency Medicine Jan 1995 25:1