Introduction. Causes of fever of unknown origin are different. It is
considered that it can be caused with over 200 different clinical entities.
Aetiological causes differ according to different categories of age.
Febricity in the elderly is at most the result of autoimmune processes,
malignancies, bacterial infections and vasculitis. Objective. The aim of this
study was to determine the most common characteristics of fever, the most
common laboratory, bacterial and viral tests and to analyze applied therapy
in patients with unknown febrile state, and to affirm final diagnosis in
elderly patients, as well as younger than 65 years old, and to define outcome
of disease in both groups of patients. Methods. Research comprised 100
patients who had been treated at the Infectious Disease Clinic of the
Clinical Centre of Vojvodina in Novi Sad, during a three-year period, and in
whom fever of unknown origin had been diagnosed. Patients were divided into
two homogenous groups of 50 people. The first one (S) consisted of patients
older than 65 years, and the second, control group (K) was constituted of
patients younger than the age of 65. All of them were chosen by random sample
method. Results. Average results of standard laboratory parameters of
infection were obtained, such as erythrocyte sedimentation rate (ESR),
fibrinogen, CRP, and especially leukocyte, and those were significantly
higher in the group of elderly patients. The cause had not been found in 10%
of elderly patient group, and in the younger group, not even in the third of
patients. Among known causative agents dominant were infections, usually of
respiratory and urinary tract, in both tested groups. Even 28% of the elderly
had sepsis, and 10% endocarditis. Malignant diseases were more frequent in
group of the elderly patients, and immune i.e. systematic disorders were
evenly noticed in both groups of patients. Conclusion. Despite advanced
studies in medicine, and existence of modern diagnostic procedures, fever of
unknown origin is still today differential diagnostic problem.
Fever of unknown origin: Most frequent causes in adults patients
