Non-respiratory tuberculosis

Abstract

The number of cases of tuberculosis (TB) in the world was estimated to be 7.9 million cases (95 per cent confidence interval (CI), 6.3-11.1) and 1.8 million (1.4-2.8) deaths per year1 and rising by at least 1 per cent per annum.Whilst the majority of cases are respiratory, the proportion of cases with non-respiratory disease is rising in both developed and developing countries, but for different reasons. In developed countries, particularly in Europe, but also in the USA,2 an increasing proportion of cases of TB are occurring in ethnic minority groups which have both a much higher incidence of TB and also a higher proportion of non-respiratory disease. In England and Wales for example in 2005, only 27 per cent of cases were in the white ethnic group, with 73 per cent of cases from non-white ethnic groups and 67 per cent of all cases being foreign born.3 In England and Wales in the national survey of 1993, the most recent to report detailed sites of disease, 32 per cent of previously untreated cases had non-respiratory disease.4 There were important ethnic differences with over half of all non-respiratory disease coming from the 3 per cent of the population of South Asian ethnic origin. Only 22 per cent of white cases had non-respiratory disease, compared with 35 per cent of other ethnic groups and 42 per cent of the South Asian cases (Table 10.1). Even within non-pulmonary sites there were ethnic differences. In all ethnic groups, lymph node disease was the most common site, with 38, 47 and 63 per cent of white, South Asian and other ethnic groups respectively, whereas bone/joint TB was proportionately higher in white (15 per cent) and South Asian (14 per cent)tourinary cases were higher in white cases (17 per cent) than in South Asian (3.7 per cent) and other ethnic groups (5.6 per cent) (Table 10.1).