Tuberculosis case-finding in Western Australia

The records of a total of 497 patients notified to have active tuberculosis (TB) in Western Australia from 1986 to 1990 inclusive have been reviewed in relation to case-finding. Of these, 276 (55.5%) were Asian migrants, 92 (18.5%) Europeans and 110 (22.1%) Australians. The disease was confirmed bacteriologically in 247 (49.7%). The most common mode of diagnosis was symptomatic presentation (39.8%), followed by migrant health surveillance (36.8%), incidental finding (7.5%), regular follow-up (3.8%) and pre-employment chest radiography (1.8%). Contact examination in the non-Asians accounted for only 0.4% while diagnosis after death 2.6%. There was no statistical difference in the detection of TB disease and infection among contacts of index patients with diseases at different sites or of different bacteriological status. The results of the study justify the present strict surveillance over the Asian migrants but do not support the overcautious policy of the contact examination procedures in the non-Asians, for which changes are proposed. Twelve patients whose confirmed TB was diagnosed only at autopsy had a mean age of 75.4 (range 41-86) years. Six of them had miliary or disseminated TB, three co-existing serious medical conditions and none a past history of the disease. The pattern has been well described and clinicians should keep a high index of suspicion for TB in this group of patients.