[Osteomyelitis, a cause of prolonged fever in adults].

A 35 years old male patient with an unexplained prolonged fever, after serial unsuccessful investigations in 3 different services, suffers a fracture of the lower third of the right femur produced by a minor trauma. This raises the suspicion of a pathological fracture. The surgical intervention and the microbiological exam confirms the existence of an osseous infection with Gram-negative germs, and the clinical course is uneventful after stabilization with an external fixator and appropriate antibiotic therapy. Osteomyelitis, although rare in adults, should be included in the differential diagnosis of any prolonged fever of unknown origin in adults.