[Vegetative hyperthermia: a thermoregulation disorder or a variant from the norm?]

A diagnosis of low-grade idiopathic fever was made in 85 women and 15 men, examined for subfebrile temperature of unknown origin, after organic disease had been excluded. Compared with 100 healthy control subjects these patients had inadequate movement-dependent temperature elevations with a usually pronounced discrepancy between the rectal temperature, predominantly more than 38 degrees C, and a normal or only slightly raised axillary temperature recorded after bodily movement. Other characteristics were that the elevated temperature was uninfluenced by antipyretic drugs. Almost all patients initially complained about general lassitude as well as frequently about atypical functional complaints and psychological symptoms. These observations indicate that low-grade fever is a functional syndrome due to a harmless faulty regulation of body temperature. In addition to a special constitutional reactivity, psychological factors and possibly previous febrile infections are likely to be involved as precipitating causes.