Clinical features of immunocompromised and nonimmunocompromised patients with pulmonary tuberculosis

Although patients with risk factors for tuberculosis have increased with the increased use of immunosuppressive therapy, there have been few reports about differences in clinical findings between immunocompromised patients and nonimmunocompromised patients with pulmonary tuberculosis. Therefore, we investigated differences between the clinical features of immunocompromised patients with pulmonary tuberculosis and those of nonimmunocompromised patients in the past decade. We analyzed findings in 840 patients (312 immunocompromised and 528 nonimmunocompromised) with pulmonary tuberculosis who were found to be culture-positive for Mycobacterium tuberculosis between January 1997 and December 2006. The characteristic clinical findings of the immunocompromised patients, compared with findings in the nonimmunocompromised group, were as follows: (1) an increase in the number of patients with respiratory symptoms during the period of follow-up of underlying diseases; (2) an increase in the number of patients in a hyponutritional state and with a negative response for the tuberculin skin test; (3) an increase in the number of microbiologically smear-positive sputum specimens; (4) an increase in the number of patients with atypical radiological findings, such as a few cavities or calcification, bilateral and expansive consolidation, miliary shadows, and mediastinal and/or hilar lymphadenopathy ; (5) an increase in the number of patients with misdiagnosed pneumonia at admission; and (6) an increase in the mortality rate. We concluded that, among the immunocompromised patients with pulmonary tuberculosis, there were many patients with atypical radiological findings and with smear-positive findings for acid-fast bacilli examination that was carried out to isolate M. tuberculosis (which had become infectious). We must perform the acid-fast bacilli examination for patients who have a fever and continuous cough, and antituberculous drugs should be administered as soon as possible when the results are positive.