Pulmonary tuberculosis in the adult in a low prevalence area: is the radiological presentation changing?

Pulmonary division of a university hospital in Belgium, an area with a relatively low tuberculosis incidence (14.9 per 100 000 population in 1993).

To evaluate whether 'unusual' radiographic presentations of pulmonary tuberculosis (PTB) have increased in recent years, especially in elderly and non-indigenous patients.

Retrospective study of chest X-rays of 219 patients aged over 18 years with bacteriologically proven PTB in the period 1981-1990, including 92 elderly (> or =65 years) and 17 non-indigenous patients. 'Unusual' presentations consisted of solitary pleural effusion, isolated hilar or mediastinal lymphadenopathies, normal chest X-ray, lower lung field TB, nodular lesions, diffuse infiltrations and atelectasis.

There was an increase in 'unusual' presentations, from 24% in 1981-1985 to 35% in 1986-1990, yet this was not statistically significant (P = 0.08). This increase tended to be more pronounced in the elderly age group, i.e., from 24% to 42% compared to 23% to 31% in the younger age group. The proportion of elderly patients in the group with 'unusual' findings was 44% in 1981-1985 and 48% in 1986-1990. In the non-indigenous group, the percentage of 'unusual' findings did not change between the two periods (40% versus 41%). The proportion of non-indigenous patients in the group with 'unusual' findings increased from 7% in 1981-1985 to 13% in 1986-1990; however, this difference was not significant.

In an area with low TB incidence, adult PTB still presents with the classical pattern of reactivation disease. Although not statistically significant, there is a trend towards a relative increase in the frequency of unusual presentations in recent years, which is most pronounced in the elderly and in non-indigenous adults.