[Osteomyelitis of the tibial head caused by Mycobacterium haemophilium in a patient with AIDS].

HISTORY AND ADMISSION FINDINGS

A 53-year-old man with known HIV infection and AIDS was admitted because of painful swelling at the right knee for 6 weeks. The cause was thought to be osteomyelitis and surgical treatment was planned.

INVESTIGATIONS

No causative pathogen was found at curettage and lavage of an abscess at the right medical head of the tibia, but at a subsequent operative revision acid-fast rods were seen and identified as Mycobacterium haemophilum.

TREATMENT AND COURSE

A systemic antibiotic, 1 g levofloxacin daily, had been started at the initial abscess operation. 2 weeks later, because swelling of the right knee had recurred with marked local and systemic signs of infection, a second surgical intervention was performed. Afterwards, in view of the histological finding of acid-fast bacteria suggesting tubercular osteomyelitis, the patient was put on combined treatment with 300 mg/d of isoniazid, 1600 mg/d of ethambutol, 2 g/d of pyrazinamide, and 1 g of streptomycin i.m. every other day. After molecular microbiological identification of M. haemophilum the antibiotic treatment was changed to 1600 mg/d of ethambutol, 300 mg/d of rifabutin and 1 g/d of clarithromycin. The operation wound healed well.

CONCLUSION

M. haemophilum infection can be lethal in immunodeficient patients if untreated. Although there is no standard treatment, this rare infectious disease responds relatively well to a modified combined tuberculostatic regimen. Special laboratory techniques to identify the specific causative pathogen are therefore of great importance.