Assessment and management of active and latent TB.

More than 25% of the world population has been infected with tuberculosis (TB), however only 10% of those infected will ever develop active disease. Clinically significant disease occurs through progression of primary infection or through later reactivation of latent TB infection (LTBI); this is most likely to occur in the first few years following infection, although late reactivation can occur several decades later, particularly in individuals who become immunosuppressed. Risk of TB acquisition is increased in people who have come to the UK from high incidence countries or who are born in the UK but come from high-risk ethnic minority groups. In 2015, 73% of those diagnosed with active TB were born outside the UK. Other risk groups include those who are homeless, in prison or who misuse drugs or alcohol. Once infected people who are immunosuppressed are at greater risk of progression to active disease. Infants below the age of 12 months can develop rapidly progressive and potentially fatal infection. Initial clinical assessment with chest radiography and the collection of three deep respiratory samples for smear microscopy and culture remain the standard of care. The management of active TB has not changed significantly over many years. The most significant changes in the 2016 NICE guidance relate to screening for LTBI in individuals who are contacts of a patient with active TB, or who are recent entrants to the UK from a high incidence country. NICE recommends that only contacts of patients with active pulmonary or laryngeal TB be screened.