A Roadmap for Fever of Unknown Origin in Children

Abstract

Fever of unknown origin (FUO) in adults is conventionally defined by the occurrence of body temperatures above 38.3°C (101°F) for a period of 3 weeks without any identified etiology after a period of 1-week hospitalization. The issue of FUO in pediatrics is rather hazy and still represents a challenging diagnostic dilemma. Most of the available data are limited to nationwide cohorts of patients of any age. The major difficulty in establishing a diagnosis is that the characteristic features rendering specific disorders clinically recognizable are absent or subtle, hence only a painstaking questioning on family background may elicit the correct investigative path. No diagnostic algorithms are actually available and clinicians must rely on a very careful step-by-step evaluation of the single patient. The need for invasive diagnostic techniques should be closely taken into consideration when laboratory tests or simple imaging procedures fail to discern the origin of FUO. Fevers with no reasonable explanation and no localizing signs often conceal different common diseases in children, which tend to display an unusual or atypical pattern. The principal causes behind FUO in pediatric age remain infections, followed by collagen vascular diseases and neoplastic disorders, although most children with malignancies present other systemic signs or suggestive laboratory abnormalities. The possibility of autoinflammatory syndromes, drug fever, and factitious fever should also be taken into account.

Fever of Unknown Origin in Children Aged Three Months to Fifteen Years

“…The reason for this variation would be the place of the study and variation in age of the patients (8). The prevalence of FUO related diseases is different according to the geographical region and age (4,(9)(10)(11)(12)(13)(14)(15). In the developing countries such as Iran, the most common cause of FUO is infectious disease and in conclusion, infectious respiratory along with TB are the most common infectious diseases for the children with FUO.…”

Paniculitis como manifestación de síndrome febril prolongado en pediatría: Caso clínico

“…In the 1960s, Petersdorf and Beeson conducted a prospective study at Yale University with a sample of 100 patients with body temperature above 38.3 ° C for more than 3 weeks without diagnosis, despite a week of etiological study hospitalized, coining the term "fever of unknown origin" (FOD) 1,2 ; The FOD is equivalent to the concept of prolonged febrile syndrome (PFS), which in adults maintains the 3-week temporality criterion, but in pediatrics it is currently defined as a febrile episode of at least 7-10 days of evolution, without etiological diagnosis, despite an initial study consisting of anamnesis and complete physical examination together with basic laboratory tests [2][3][4] .…”

“…As to the etiology of this syndrome, infectious, immunoreumatological, neoplastic and miscellaneous causes are distinguished [1][2][3][4] . After an exhaustive study, in 10-32% of cases, according to geographic location, no etiology is determined [2][3][4][5][6][7][8][9] .…”

“…After an exhaustive study, in 10-32% of cases, according to geographic location, no etiology is determined [2][3][4][5][6][7][8][9] . It should be mentioned that identifying the etiological diagnosis can be complex, due to atypical presentations of frequent clinical pictures [3][4][5] .…”

“…Establishing that the PFS is a diagnostic challenge for the medical team, it is necessary to carry out a systematic study, following a logical order that allows optimizing resources and avoiding diagnostic delays, to the benefit of the patient 3,4,10 .…”