Tuberculosis in children

Key points

• Tuberculosis (TB) is a major cause of morbidity and mortality worldwide. Children with TB are markers of recent disease transmission, usually from infectious adults. The 1 million cases of TB in children registered each year is likely to be a gross underestimate.

• The diagnosis is challenging and often presumed rather than confirmed. Symptoms, if present, are nonspecific.

• TB infection occurs when a previously uninfected child inhales an infected aerosol droplet. At this stage, the child usually shows no symptoms, the infection passes undetected and the primary focus heals. In most cases the infection is controlled by the body's immune system and the organisms remain dormant. This is called latent TB. TB disease can develop either then or at a later stage when the organism multiplies, overpowering the host defences. At this stage, symptoms develop and there may be radiological or microbiological evidence of disease.

• "More bugs require more drugs". In TB infection, the organism load is small and therefore drug-resistant mutations are rare: hence simpler drug regimes are effective. In TB disease, the number of organisms is greater, so a combination of ≥3 drugs is required. Increasing resistance worldwide has led to four drugs being recommended as standard in many areas.

• Poor adherence to drug therapy is the main barrier to cure. Although directly observed therapy (DOTS) and intermittent therapy may improve the outcome, neither is a panacea. Co-operation and other strategies are required.

• Bacille Calmette-Guérin (BCG) vaccination remains the most widely used preventative strategy. Its efficacy is uncertain and its use needs to be targeted to neonates in high-risk areas who are most likely to benefit. The development of new vaccines against pulmonary TB is an important global challenge.

Educational aims

• To describe the epidemiology and natural history of TB in children, focusing on pulmonary TB.

• To explore the challenges of diagnosis and provide an up-to-date overview of the methods available.

• To outline the management and prevention of pulmonary TB in children.

Summary Despite advances in diagnosis, treatment and prevention, tuberculosis (TB) remains a major cause of mortality and morbidity worldwide. Diagnosis and treatment in children present a challenge, particularly in the face of growing drug resistance and coexistent disease such as HIV. New diagnostic methods have not yet been fully validated for use in children. No new drugs have become available in the past 30 years and many of the commercially available preparations are unsuitable for children. In 2006, a number of major documents and strategies were launched aimed at improving the care of children with TB, a previously neglected area.