Some current concepts on childhood tuberculosis

As children acquire infection with Mycobacterium tuberculosis from adults in their environment, the epidemiology of childhood tuberculosis (TB) follows that in adults. While global burden of childhood tuberculosis is unclear, in developing countries the annual risk of tuberculosis infection in children is 2- 5 per cent. Nearly 8-20 per cent of the deaths caused by tuberculosis occur in children. It has been suggested that BCG vaccination is responsible for decrease in the occurrence of disseminated and severe disease. Localized forms of illness, e.g., intrathoracic lymphadenopathy, and localized CNS disease have been reported to occur with greater frequency in vaccinated children. Human immunodeficiency virus (HIV) infected children are at an increased risk of tuberculosis, particularly disseminated disease. Diagnosis of TB in children presents special problems as the sputum is generally not available for examination. Diagnostic algorithms include scoring system utilizing clinical parameters and results of investigations. Various diagnostic techniques such as improved culture techniques, serodiagnosis, and nucleic acid amplification have been developed and evaluated to improve diagnosis of childhood tuberculosis. Serodiagnosis is an attractive investigation but till date none of the tests showed desirable sensitivity and specificity. Tests based on nucleic acid amplification are a promising development. Relatively less experience in children, need for technical expertise and high cost are the limiting factors for their use in childhood tuberculosis. Short-course chemotherapy for childhood tuberculosis is well established. Treatment with intermittent regimens is comparable to daily regimens. Directly observed treatment strategy (DOTS) has also shown encouraging results. Pattern of drug resistance among children with TB tends to reflect those found among adults in the same population. The rates of drug resistance to any drug vary from 20 to 80 per cent in different geographic regions.