Diagnosis and management of undifferentiated fever in children.
Long, Sarah S · The Journal of infection · 2016 · DOI
Quick Summary
This medical guideline helps doctors figure out what causes unexplained fevers in children and how to treat them. The article explains that many children who come to doctors with persistent tiredness after a fever may not have a serious infection—instead, they might just be deconditioned (out of shape) and need to gradually return to normal activities like school and exercise.
Why It Matters
This guideline is relevant to ME/CFS because it addresses how clinicians differentiate between true infections and post-viral fatigue syndromes in young patients. The recognition that persistent fatigue following acute febrile illness can represent deconditioning rather than ongoing infection is important for understanding how ME/CFS may be misclassified or underdiagnosed in pediatric populations.
Observed Findings
Diagnostic capabilities have improved, changing the epidemiology of FUO over recent decades
Adolescents with persistent fatigue complaints following acute febrile illness are sometimes referred for evaluation as FUO
Thorough history and physical examination combined with normal laboratory findings can suggest a diagnosis of 'fatigue of deconditioning'
Management approaches differ by age group, with infants under one month requiring urgent investigation while older children can often be managed clinically
Inferred Conclusions
History and physical examination remain paramount in evaluating fever and fatigue complaints in children
Not all persistent fatigue after acute febrile illness represents serious infection; deconditioning may be the underlying cause
Clinical judgment should be tailored to patient age and observable signs rather than relying solely on temperature measurements
Reconditioning and return to normal activities may be appropriate 'treatment' for fatigue of deconditioning
Remaining Questions
How can clinicians reliably distinguish between true post-viral syndromes (such as ME/CFS) and fatigue of deconditioning in adolescents?
What are the objective biomarkers or clinical features that would help identify which patients with persistent post-febrile fatigue have underlying pathology versus deconditioning?
What This Study Does Not Prove
This guideline does not establish diagnostic criteria for ME/CFS or prove that deconditioning is the primary cause of post-viral fatigue in all cases. It does not provide evidence about the pathophysiology of fatigue syndromes, nor does it address whether some cases of persistent fatigue involve immunological or metabolic dysfunction rather than simple deconditioning.
About the PEM badge: “PEM required” means post-exertional malaise was an explicit required diagnostic criterion for participant inclusion in this study — not that PEM was studied, observed, or discussed. Studies using criteria that do not require PEM (e.g. Fukuda, Oxford) are tagged “PEM not required”. How the atlas works →