Because of the rising burden of tuberculosis worldwide, the World Health Organization took the unprecedented step of declaring a global tuberculosis emergency in 1993. Children constitute a significant proportion of the tuberculosis caseload, up to 40% in high burden settings, and experience considerable tuberculosis-related morbidity and mortality.1,2 Childhood tuberculosis is regarded as a paucibacillary disease that is difficult to diagnose and that poses little risk of Mycobacterium tuberculosis transmission. However, children older than 10 years of age develop a different spectrum of disease compared with younger children, with the majority developing adult-type cavitating disease that is sputum smear-positive.3,4 This emphasizes the importance of correct disease classification in childhood tuberculosis, both for prognosis and estimation of the transmission risk.5 We report 8 children (10–14 years of age) who were diagnosed with tuberculosis at their local primary health care clinic in Cape Town, South Africa during a period of 3 months (July–September 2004); after routine sputum testing was extended to all children older than 10 years of age with suspected tuberculosis.
During the 3-month period, 92 cases of tuberculosis were recorded in total. Children (younger than 15 years of age) constituted 22.8% (21 of 92) of the total disease burden. All sputum smear-positive disease occurred in those 10 years of age or older. In total, 65 (70.6%) cases were sputum smear-positive, of whom 7(10.8%) were children 10–14 years of age. One child in this age group, with a large pleural effusion and blistering tuberculin skin test, were sputum smear-negative. The male-female ratio was 2:6, and none of these children was infected with human immunodeficiency virus. The majority (6 of 8, 75.0%) reported known contact with a sputum smear-positive source case in the preceding 6–18 months (Table 1). All of the children were still at school.
Table 1 describes the clinical presentation and disease characteristics of the 8 cases. Two children reported erythema nodosum (probably indicative of primary M. tuberculosis infection) in the preceding year. Two children had a tuberculous pleural effusion, of whom 1 had additional parenchymal cavitation and was sputum smear-positive. Both presented with intense, localized pleuritic chest pain, accompanied by fever. Most children without pleural effusion (4 of 6, 66.7%) reported vague and poorly localized chest pain. The children with sputum smear-positive disease had high organism loads as reflected by their sputum smear grading. Complete symptom resolution occurred within 2 months of treatment in 7 (87.5%) cases, using the standard initial four-drug treatment of isoniazid, rifampin, pyrazinamide and ethambutol in a combined fixed dose tablet. Treatment adherence during the intensive phase was excellent (>90% of prescribed doses in all cases). Sputum smear conversion was documented in all 7 sputum smear-positive cases after 2 months of treatment. At this time, only 1 child reported incomplete symptom resolution, although she did show significant symptomatic and radiologic improvement. This was attributed to the extent of disease at diagnosis, and her treatment was continued with the standard short course (6 months) treatment regimen.
Despite the methodologic limitations, this case series highlights a few clinical observations with important public health implications. It illustrates that tuberculosis in children 10–14 years of age frequently presents like adult tuberculosis,6 and that the majority of these children can be diagnosed with routine sputum smear microscopy at the primary health care level. It is well-known that adolescent girls are at higher risk to develop tuberculosis after recent primary infection than are boys.3,4 Erythema nodosum may represent a marker of recent primary M. tuberculosis infection, identifying those with a particularly high risk of progression to tuberculosis in the coming months.7
It is difficult to establish the exact time of M. tuberculosis infection, but it is striking that 75% of children had known contact with a sputum smear-positive source case in the preceding 6–18 months. This correlates with the natural history of disease, which indicates that adolescent children are at high risk to develop adult-type tuberculosis within 1–2 years after primary infection.3,7 Therefore all contacts of sputum-smear positive source cases, especially adolescent girls, should be informed about their risk to develop tuberculosis, even if their initial screening tests are negative. Persistent, nonremitting symptoms should be reported without delay, and tuberculosis should be excluded. Delayed diagnosis poses a significant transmission risk to the community, especially fellow pupils8 and household members.
We thank Sister L. E. Mpambaniso and staff nurse G. N. Summers for their diligence in identifying the patients and assisting with data collection; the patients for their kind assistance; and the local health authorities for permission to report the findings.
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