Diagnostic des ostéites chroniques

Chronic osteitis is secondary to acute bone infection non or under-treated. Pathophysiological mechanisms are multiple and complex. Diagnosis is difficult, which delays management. Clinical signs of chronic osteitis are nonspecific, dominated by fistula. Biological data are often inconclusive. Multiple and deep intraoperative samples are the best guarantee of a reliable diagnosis. True-cut biopsy or repeated diabetic toe cultures with bone contact are possible alternatives. Cultures are characterized by a low number of metabolically active bacteria requiring a minimum 7 days of incubation. Chronic osteitis can be polymicrobial in approximately one third of cases. Identification of the bacterial species is based on phenotypic techniques for usual bacteria or genotypic techniques for rare or hard to identify bacteria. The use of molecular biology directly from samples is justified for difficult to grow bacteria or if prior antibiotic treatment was administered. Imaging has a prominent place in the diagnosis of chronic osteitis. Conventional radiography remains essential. Computer tomography and MRI investigate bone lesions and evaluate soft tissue and medullar extension. Bone scintigraphy methods suffer from a lack of specificity ; however this can be improved by labeling leucocytes with 99mTc-HMPAO or with 111In-oxin. More recently, 18FDG-PET has proved to be superior in terms of sensibility and specificity.