Our patient was a 78-year-old man. He smoked 20 cigarettes/day from the age of 30-40. After transurethral resection of a superficial bladder tumor, BCG intravesical injection therapy was administered three times at another hospital, and a cough appeared 3 weeks after BCG commencement. A computerized tomography (CT) scan revealed multiple granular shadows suggestive of miliary tuberculosis, and the patient was referred to our hospital. Upon arrival, his temperature was 35.8  C; respiratory rate, 24 breaths/min; and SpO2, 97% (room air). Physical examination revealed no head and neck lymphadenopathy, normal heart and respiratory sounds, and no other abnormal findings. Blood tests showed a mildly elevated inflammatory reaction but no other abnormal findings. Sputum and urine smears were negative for acid-fast bacilli. The urine anti-acid test was smear-negative, and the TB-polymerase chain reaction (PCR) result was positive (Table 1). Chest radiography showed diffuse small granular shadows in the bilateral lung fields, and chest CT showed multiple small granular shadows in the bilateral lungs (Fig. 1). Miliary tuberculosis was strongly suspected from the chest CT.
Based on clinical symptoms, imaging findings, and a positive urinary M. tuberculosis complex group PCR, a preliminary diagnosis of disseminated M. bovis BCG disease mimicking miliary tuberculosis was made. Since BCG infection was suspected from the disease course and the patient was an older adult, treatment was started with three drugs (isoniazid (INH), rifampicin (RFP), and ethambutol (EB)) other than pyrazinamide (PZA) from the beginning of treatment. Anti-tuberculosis chemotherapy with INH 300 mg, RFP 600 mg, and EB 1000 mg was started. Seventeen days later, a urine mycobacteria culture was positive for M. tuberculosis complex, and then the cultured microorganism was identified as M. bovis BCG using multiplex PCR. Drug sensitivity showed that the patient was resistant to pyrazinamide but sensitive to other drugs, and the treatment was continued without any changes. The patient's subjective symptoms improved over time, and the miliary shadowing disappeared on CT (Fig. 1).