Antibiotic-induced fever in orthopaedic patients-a diagnostic challenge.

INTRODUCTION: Antibiotic-induced fever is a probably underestimated complication, which may be misdiagnosed as new infection. In this study, characteristics, diagnostic approach, and outcome of antibiotic-induced fever in patients treated for musculoskeletal infections are described. METHODS: We retrospectively reviewed all patients with antibiotic-induced fever after surgery treated at our institution from 2014 to 2017. Antibiotic-induced fever was diagnosed, if the following criteria were fulfilled: (i) central (ear) body temperature > 38.0 °C; (ii) intravenous antibiotics for > three days; (iii) exclusion of infectious or other non-infectious causes of fever; and (iv) defervescence after discontinuation of antibiotics. RESULTS: We included 11 patients (median age 51 years) treated for infection after fracture fixation (n = 5), periprosthetic joint infections (n = 3), infection after spinal instrumentation (n = 1), and soft tissue infection (n = 2). The suspected antibiotics inducing fever were beta-lactam antibiotics (n = 9), vancomycin (n = 3), daptomycin (n = 2), clindamycin, and meropenem (n = 1 each). Additional clinical findings were reduced general condition, generalized exanthema, and rigors, whereas five patients were asymptomatic apart from a fever. Leukopenia was observed in nine patients and increase of C-reactive protein value in ten patients. Fever occurred after a median of 20 days of antibiotic treatment and resolved after a median of one day after discontinuation of the suspected antibiotic. CONCLUSIONS: Antibiotics should be considered as the possible cause of fever in orthopaedic patients receiving antimicrobial treament whenever clinical signs of new or persisting infection are lacking. Important hints suggestive for antibiotic-induced fever are good general condition despite high temperature and progressive leukopenia. Discontinuation or change to another substance leads to prompt defervescence, preventing unnecessary diagnostic procedures and antibiotic treatment.