[Fever as a very important symptom of infectious and some non-infectious diseases]

Fever is a protective and adaptive reaction, an early and obligatory symptom of infectious diseases in the first place. Historically, this term has been used in the names of more than 20 infectious diseases. Fever may also be a manifestation of other diseases accompanied by aseptic inflammation and neurohumoral disturbances. The growth rate of fever and the character of its circadian fluctuations at the beginning of the disease, as well as its total duration, the height and type of temperature curve, and time of onset of organic lesions should be taken into consideration when performing differential diagnostics of fevers of different origins. The authors developed an algorithm of differential diagnostics of febrile conditions. When an infectious process is excluded reasonably, the patient should undergo further examination for early detection of other diseases accompanied by fever.