Recurrent tuberculosis in a psychiatric hospital, recurrent outbreaks during 1987-1996

During 1987-1996, 39 of 720 patients hospitalized (most for severe schizophrenia) were diagnosed as having active pulmonary tuberculosis (5.4%, 975 per 105 per year). In 1992-1993, after a cluster of 5 cases was found, all patients were screened by PPD skin test and chest X-ray and 16 more cases were identified. Diagnosis was confirmed bacteriologically in only 10 of them but there were typical radiological findings in the others. 39 were treated with a multi-drug regimen. In addition, 333 exposed patients and 21% who had converted their skin tests were given isoniazid preventive therapy. A small increase in levels of liver enzymes was common, but significant abnormality (over 4 times the upper limit of normal) was found in only 7 patients, in whom therapy was therefore stopped or changed. During a follow-up period of 4 years, 2 more developed tuberculosis and 33 converted their PPD reactivity status. We conclude that an outbreak of tuberculosis in a psychiatric hospital can be controlled with a relatively low rate of side-effects by using systematic diagnostic and therapeutic measures. However, single step screening is not sufficient. Routine screening of all new patients, a high index of suspicion and contact investigation are needed.