[X-ray-negative endobronchial tuberculosis with persistent irritating cough that resulted in unpredicted mass infection].

A 24-year-old woman was referred to another hospital because of a barking cough, but her chest radiograph showed no abnormality. Although she had been diagnosed as having other diseases and had been given medical treatment, the barking cough continued. Abnormalities of the chest radiograph appeared 11 months later, and endobronchial tuberculosis was diagnosed from the clinical history, chest CT and a sputum smear positive for acid-fast bacilli. We treated her with INH, RFP, EB for 6 months, and PZA for 2 months. However, truncus intermedius became obstructed nine months after treatment ended, and we re-opened it with a Dumon stent after coring it out using a rigid bronchoscope. Since the patient was a teacher, medical checkups of many people were required, and the number of prophylactic treatments carried out was 80. This was regarded as a mass infection. In the early stages, endobronchial tuberculosis may not show any abnormality on chest radiography, but may still cause mass infection. When a barking cough continues for a long time, endobronchial tuberculosis must be suspected, and examination of a sputum smear for acid-fast bacilli, as well as a sputum culture is necessary.