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BACKGROUND: Although there are theoretical reasons for believing that asthma and atopy may be negatively correlated with tuberculosis, epidemiological studies have had conflicting findings. OBJECTIVE: To determine if people with confirmed tuberculosis were less likely to be atopic and less likely to have atopic disease including asthma compared to those with no previous tuberculosis. METHODS: Patients in Lima, Peru with a prior history of tuberculosis were identified from clinic records in this cohort study. A representative sample of individuals without a prior tuberculosis diagnosis was recruited from the same community. Allergen skin prick testing was performed to classify atopic status. Allergic rhinitis was identified by history. Asthma was defined by symptoms and spirometry. Eosinophilic airway inflammation was measured using exhaled nitric oxide levels. RESULTS: We evaluated 177 patients with, and 161 individuals without, previous tuberculosis. There was a lower prevalence of atopy among people with prior tuberculosis on univariate analysis (odds ratio 0.57; 95% confidence interval 0.37-0.88) but, after adjustment for potential confounders, this was no longer statistically significant (aOR 0.64, 95% CI 0.41-1.01). The prevalence of allergic rhinitis (aOR 0.76, 95% CI 0.47 to 1.24 and asthma (aOR 1.18, 95% CI 0.69 to 2.00) did not differ significantly between the two groups. We also found no significant difference in the prevalence of elevated exhaled nitric oxide (aOR 1.30, 95% CI 0.78 to 2.17) or a combined index of atopic disease (aOR 0.86, 95% CI 0.54 to 1.36). CONCLUSION: In this urban environment in a middle-income country, prior tuberculosis may be associated with a reduced risk of atopy but does not protect against asthma and atopic disease.

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The burden of childhood tuberculosis remains poorly known in the world. The diagnosis is challenging because tuberculosisin children is generally bacteriologically negative. Recent studies have described diagnostic techniques involving molecular biology, advances in the standard treatment andnew antituberculosis drugs, however, the diagnosis continues to be based on current clinical data, radiological imaging studies and epidemiological investigation.Over the last decade, the treatment of childhood tuberculosis has improved because of scientific advances and international standardization of practices.

A situação mundial da tuberculose na infância é pouco conhecida. O diagnóstico é um desafio porque a tuberculose na infância é geralmente negativa bacteriologicamente. Estudos recentes descrevem técnicas de diagnóstico por biologia molecular, avanços no tratamento padronizado e novos fármacos; entretanto, o diagnóstico tradicional ainda se baseia em dados clínicos atuais e em estudos radiológicos e epidemiológicos. A tuberculose na infância incorporou avanços científicos e condutas padronizadas internacionalmente na ultima década.

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One of the fascinating aspects of childhood tuberculosis (TB) is the diverse spectrum of pathology, which necessitates accurate disease classification. This manuscript provides a brief overview of the disease diversity observed in children with TB, with particular emphasis on adult-type TB. Cavitary disease in children may result from three distinct pathologic processes; 1) poor containment within the Ghon focus (mainly very young and/or immune compromised children), 2) aspiration of virulent bacilli following eruption of a diseased lymph node into an airway with resultant caseating pneumonia and parenchymal destruction (mainly children < 5 yrs of age), and 3) from adulttype disease (mainly children > 10 yrs of age). The exact pathological mechanism underlying adult-type disease remains uncertain. The combination of a destructive cell mediated immune response together with increased organism survival and proliferation in the lung apices, may initiate a vicious circle of parenchymal destruction. This hypothesis may explain the sudden emergence of adult-type disease around puberty, as well as the typical anatomical location of the lung cavities. Most children with adult-type disease are sputum smear-positive and can be diagnosed with routine sputum smear microscopy at primary health care level. Due to the high organism load the same treatment rationale used in adults with sputum smear-positive TB would apply, which justifies the use of four drugs during the initial intensive phase. These children pose a considerable transmission risk, particularly in congregate settings such as schools, and screening of close contacts should also be considered

Uno de los aspectos fascinantes de la tuberculosis (TB) infantil es el amplio espectro de las alteraciones histopatológicas, lo que requiere una clasificación precisa de los hallazgos. Este manuscrito proporciona un breve panorama general de la diversidad de presentaciones clínicas observadas en los niños con TB y hace hincapié particularmente en la TB que imita las formas del adulto. La enfermedad cavitaria en los niños puede ser el resultado de tres procesos anatomopatológicos distintos: 1) la escasa limitación dentro del foco de Ghon (principalmente en los niños muy pequeños o inmunocomprometidos), 2) la aspiración de bacilos virulentos luego de la erupción de una adenopatía en una vía aérea con neumonía caseosa consiguiente y destrucción del parénquima (principalmente en los menores de 5 años) y 3) la enfermedad de tipo adulto (principalmente en los niños mayores de 10 años). Es incierto aún el mecanismo fisiopatológico exacto subyacente a la enfermedad de tipo adulto. La combinación de una intensa respuesta inmune mediada por células junto con la mayor supervivencia y proliferación del microorganismo en los vértices pulmonares puede iniciar un círculo vicioso de destrucción parenquimatosa. Esta hipótesis puede explicar la aparición súbita de la enfermedad de tipo adulto alrededor de la pubertad, así como la localización anatómica típica de las cavidades pulmonares. La mayoría de los niños con enfermedad de tipo adulto tienen frotis de esputo positivos y el diagnóstico se puede realizar con la microscopia de rutina del frotis de esputo en la atención primaria. Debido a la gran carga de microorganismos se debe aplicar el mismo fundamento terapéutico utilizado en los adultos con TB con frotis de esputo positivo, lo cual justifica el uso de cuatro drogas durante la fase intensiva inicial. Estos niños plantean un riesgo considerable de transmisión, sobre todo en comunidades cerradas como las escuelas y también se debe considerar la pesquisa de los contactos cercanos

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