THE DIAGNOSTIC USEFULNESS OF BONE-MARROW CULTURES IN PATIENTS WITH FEVER OF UNKNOWN ORIGIN

Bone marrow cultures (BMCs) and blood cultures (BCs) are frequently ob tained in the evaluation of fever of unknown origin (FUO). However, th e low yield of clinically significant isolates leads to questions abou t their cost-effectiveness. We retrospectively compared BMC with BC an d studied the usefulness of bone marrow trephine biopsy (BMTB) histopa thology in detecting infection in an unselected population of 61 patie nts with FUO, among whom 215 BMCs had been performed. For patients who had undergone BMTB, the histopathology was evaluated for granulomas a nd microorganisms. Only 1 BMC had a clinically significant isolate, My cobacterium avium complex (MAC), which was also identified by BC. Rhod otorula rubra was found in the BMC of another patient and classified a s a contaminant. Both patients had HIV infection. No growth occurred i n BCs for the other 59 patients. Culture results for all 26 BMTB speci mens were negative; 4 contained nonnecrotizing granulomas, including t he case with MAC. BMCs are probably not justified for routine initial evaluation of FUO, but may be valuable after culture results for blood and easily obtainable tissues have been negative. Bone marrow histopa thology and special stains for microorganisms in the absence of granul omas were noncontributory.