A 9-month-old Korean girl was referred to our clinic because of a progressive inability to move her right elbow on January 9, 2007. Approximately 3 weeks ago, the child was seen by a local orthopedic physician. The parents had noted that she was reluctant to move her right arm through complete ranges. Also, the patient would cry when the arm was abducted. At that time, the doctor of the local clinic had an initial diagnosis of a pulled elbow, in which the arm was reducted and put into an arm cast. Three days later, painful swelling in her right elbow developed with the limitation in active movement and inability to rotate.
The patient was born by normal vaginal delivery with normal Apgar score. She was vaccinated with Tokyo-172 BCG on the left upper arm at one month of age. BCG vaccine was administered percutaneously by multipuncture method. She had received routine immunizations up to date including hepatitis B, diphtheria-tetanus-pertussis (DTaP), polio (IPV) in accordance with the national vaccination program guidelines. She lived in Ansan and had no history of farm or zoo visit. The patient had no previous history of illness and no known familial tuberculosis history. Physical examination revealed obvious swelling, erythema, tenderness in the area of the right elbow. Furthermore, the range of elbow movement was restricted. Other physical examinations were normal.
The laboratory results at admission revealed the erythrocyte sedimentation rate 107 mm/hr and C-reactive protein (CRP) 1+. Radiological studies suggested the lesion in the elbow. Also, MRI revealed contrast enhancement in and around the right elbow, compatible with septic elbow. Signal change and contrast enhancement in the epiphysis and metaphysis of right distal humerus were noted. These features suggested septic elbow combined with osteomyelitis. No other significant abnormal finding was shown in other skeletal areas.
Initially, septic elbow was diagnosed and surgery was performed to treat osteomyelitis of right elbow and revealed concentrated dirty granulation tissue in the elbow joint space that was removed. After operation, the child had been treated with ampicillin/sulbactam before the proper diagnosis had been established. Since the osteomyelitis lesion was refractory with antibiotic therapy, we considered mycobacterium as the pathogen. A lesion biopsy specimen was sent to the pathology department. Histopathological examination of the biopsy specimen revealed a chronic caseating granulomatous inflammatory reaction. Microscopic examination of the pus with Ziehl-Neelsen staining showed no Acid-fast bacilli but a culture of the biopsy was identified with Mycobacterium tuberculosis. As the postoperative diagnosis was osteomyelitis of M. tuberculosis, we started treatment with regimen of rifampin, isoniazid and pyrazinamide. Following the culture report, the sensitivity test showed that the strain was resistant to pyrazinamide. This sensitivity study was a distinguishing characteristic of M. bovis. Therefore, we requested multiplex polymerase chain reaction (PCR) for the Mycobacterium complex colony to differentiate the pathogen. A mycobacterium culture of the biopsy sample later revealed to have an identical amplification with the BCG Tokyo-172 strain on the multiplex PCR for the Mycobacterium complex colony (Fig. 1). Based on these findings, the diagnosis of osteomyelitis due to Tokyo-172 BCG vaccination was confirmed.
Immunological investigation for the evaluation of cellular and humoral immunity was performed, including complement CH50, C3, and C4, immunoglobulins and intracellular oxidation (dihydrorhodamine) and revealed normal findings. Therefore, immunodeficiency disorders were ruled out. In addition, an evaluation for extrapulmonary TB was negative.
The patient had been treated with a regimen consisting of rifampin (10 mg/kg body weight per day), isoniazid (10 mg/kg body weight per day) and pyrazinamide (25 mg/kg body weight per day) as an outpatient. However, after two months of treatment, MRI showed no interval change (Fig. 2). We added streptomycin (30 mg/kg body weight per day intramuscularly for 10 days) and ethambutol (15 mg/kg body weight per day) instead of pyrazinamide due to the sensitivity result. Pyrazinamide was eliminated because of it is generally considered ineffective for the treatment of BCG osteomyelitis. Following the change of regimen, debridement and curettage was again performed four months after the first surgery. The planned chemotherapy regimen was continued during 12 months. She has been followed up for 2 yr and has remained without signs of growth disturbances or impairment of function in adjacent joints. The function of the right arm was normal in terms of range of motion and activity. The most recent radiological examination showed the decrease of geographic osteolytic lesion on the distal humerus and periosteal reaction, disappearance of neighboring soft tissue swelling, which suggested improving state of osteomyelitis and arthritis. The patient recovered without complications.