Tuberculosis in neonates and infants: epidemiology, pathogenesis, clinical manifestations, diagnosis, and management issues.

Tuberculosis is one of the leading infectious causes of death and as such represents a major global health problem. Infants may develop congenital tuberculosis from an infectious mother or, most commonly, they may acquire postnatal disease by contact with an infectious adult source. Important epidemiologic, pathogenetic, and clinical data regarding the management of infantile disease are reviewed. Diagnostic evaluation includes tuberculin skin tests, chest radiography and other imaging studies, smears and cultures, examination of the cerebrospinal fluid, and polymerase chain reaction, as well as the more recent interferon-gamma assay. Pregnant women with a positive Mantoux skin test but normal chest x-ray should either start chemoprophylaxis during gestation or after delivery depending on the likelihood of being recently infected, their risk of progression to disease, as well as their clinical evidence of disease. Pregnant women with a positive Mantoux skin test and chest x-ray or symptoms indicative of active disease should be treated with non-teratogenic agents during gestation; all household contacts should also be screened. When tuberculosis is suspected around delivery, the mother should be assessed by chest x-ray and sputum smear; separation of mother and offspring is indicated only if the mother is non-adherent to medical treatment, needs to be hospitalized, or when drug-resistant tuberculosis is involved. According to the American Academy of Pediatrics, treatment of latent infection is highly effective with isoniazid administration for 9 months. This regimen may be extended to 12 months for immunocompromised patients. When drug resistance is suspected, combination therapies, which usually consist of isoniazid with rifampin (rifampicin), are administered until the results of susceptibility tests become available. Organisms resistant to isoniazid only may be treated with rifampin alone for a total of 6-9 months. All infants with tuberculosis disease should be started on four agents (isoniazid, rifampin, pyrazinamide, and ethambutol or streptomycin) until drug susceptibility is assessed. For susceptible intrathoracic tuberculosis, isoniazid, rifampin, and pyrazinamide are administered for a total of 2 months, at which point pyrazinamide is withdrawn and the other two agents are continued for another 4-10 months depending on the severity of the disease. The same regimen may be applied in extrapulmonary tuberculosis with the exception of skeletal, miliary, and CNS disease, which require daily administration of isoniazid, rifampin, pyrazinamide, and streptomycin for 1-2 months, followed by isoniazid and rifampin daily or twice weekly for another 10 months. When drug-resistant tuberculosis is suspected, a regimen of isoniazid, rifampin, and pyrazinamide plus either streptomycin or ethambutol should be initially prescribed, until the results of susceptibility tests become available. HIV-seropositive infants with pulmonary tuberculosis should receive isoniazid, rifampin, pyrazinamide, and ethambutol or an aminoglycoside for 2 months, followed by isoniazid and rifampin for a total of at least 12 months. Apart from conventional antimycobacterial agents, novel therapeutic modalities, which stimulate the host immune system such as interleukin-2 (IL-2), IL-12, interferon-gamma, and tumor necrosis factor antagonists have been tested with promising results.