Clinically benign fever of unknown origin: a personal retrospective

The purpose of this discussion has been to bring to the attention of physicians the fact that all instances of etiologically undefined persistent fever are not associated with potentially serious or life-threatening organic disease, regardless of the height of the temperature. As has been pointed out, many patients with FUO clearly have disorders that are clinically benign, and the cause of these disorders is defined much more frequently on the basis of information obtained from a detailed historic inquiry than on the basis of findings made during the most meticulous physical examination and extensive laboratory studies. These individuals are usually seen first in an outpatient setting and seldom, if ever, require hospitalization because the cause of their FUO can, with uncommon exceptions, be identified as a physiologic or emotional dysfunction, a reaction to a drug or a chemical, or a disorder that is genetically determined. Failure to recognize that even a high elevation of the temperature can represent a clinically benign situation may lead to unnecessary hospitalization, during which the many investigations that are usually carried out may serve only to reinforce the patient's concern about a serious disease. It is most important for both patients and physicians to be aware that temperature, like all other physiologic and chemical measurements in humans, is expressed by a range of values and that a temperature of 98.6 degrees F is not normal for all persons. It must also be appreciated that "normal" temperature varies with age. The newborn infant may develop high-grade fever in the absence of disease because of marked instability of the vasomotor system.(ABSTRACT TRUNCATED AT 250 WORDS)