Actinomycotic osteomyelitis of a long bone in an immunocompetent adult: a case report and literature review

• Published in: BMC musculoskeletal disorders 2019-05, Vol.20 (1), p.185-185, Article 185
• Main Authors: Ryu, Dong Jin, Jeon, Yoon Sang, Kwon, Hea Yoon, Choi, Suk Jin, Roh, Tae Hoon, Kim, Myung Ku
• Format: Article
• Language: English
• Subjects: Actinomyces; Actinomycosis; Adults; Air bases; Amoxicillin; Amputation; Anaerobic bacteria; Analysis; Bacteria; Case Report; Case reports; Child health; Chronic granulomatous disease; Clavulanate; Complications and side effects; Culture; Diagnosis; Diagnostic imaging; Diaphysis; Edema; Elderly women; Femur; Fungi; Head and neck; Health aspects; Immunocompetence; Infections; Intravenous administration; Joint surgery; Knee; Literature reviews; Long bone; Magnetic resonance imaging; Metaphysis; Methicillin; Musculoskeletal diseases; Neutrophils; NMR; Nuclear magnetic resonance; Oral cavity; Osteomyelitis; Outcome and process assessment (Medical care); Pain; Pathology; Patients; Pediatrics; Penicillin; Penicillin G; Penicillins; Polymerase chain reaction; Recurrence (Disease); Risk factors; Tissue culture; Trauma; Tuberculosis; Wound drainage
• ISSN: 1471-2474; 1471-2474
• DOI: 10.1186/s12891-019-2576-2

Actinomycosis is a rare, chronic granulomatous disease caused by Gram-positive anaerobic bacteria that colonize the oral cavity. Cervicofacial actinomycosis is the most frequent clinical presentation of actinomycosis, but hematogenous osteomyelitis at distant sites can occur in rare instance in immunocompromised or pediatric patients, only a few cases have been reported in healthy patients. Here we described a new case of distal femur osteomyelitis caused by Actinomyces in an adult patient who was immunocompetent and had no predisposing factors. A woman aged 52 years with no history of trauma presented with severe pain, swelling, and increased local heat in the proximal area of the right knee 3 weeks after she first noticed discomfort. Magnetic resonance imaging showed persistent osteomyelitis of the distal metaphysis and diaphysis of the femur with a multifocal intraosseous abscess pocket. An incision and drainage of the abscess were conducted. The tissue culture, fungus culture, acid fast bacillus (AFB) culture, AFB smear, and tuberculosis polymerase chain reaction test results were negative. A pathologic examination confirmed the presence of actinomycosis. The patient was successfully treated with intravenous penicillin G for 8 weeks followed by oral amoxicillin-clavulanate for 6 weeks with repeated surgical debridement and drainage. After a 5-year follow up, the patient had no signs of recurring infection or complications and she had full range of movement in the affected knee. Although rare, actinomycotic osteomyelitis can occur in healthy people. Furthermore, actinomycotic osteomyelitis is easily misdiagnosed as tuberculosis in areas with a high prevalence of tuberculosis. To detect and identify the bacteria accurately, pathologic examination should be performed as well as culture tests, because the probability for culture confirmation of actinomycosis is quite low. The initial treatment is vital to a successful outcome without ostectomy or amputation.