[Difficulties in the treatment of tuberculosis in infants]

Nowadays, methods of the diagnosis in infants with suspected tuberculosis and of the treatment are definitely established in Japan, where a number of childhood tuberculosis has been falling down (the incidence is less than 2 per 100,000). Still, infants less than one year are considered to be at high risk against tuberculosis. Actually, the number of tuberculosis among them is three times larger than those of one or two years old children. One of major reasons of difficulties in the treatment is the rapid progress of the disease because of underdeveloped cell-mediated immunity among them. Alveolar macrophage and lymphocyte and their cooperation in immunological functions do not develop enough to kill or confine Mycobacterium tuberculosis. As a result, the infection may progress to disease quickly, and then may spread systemically before the starting treatment. Anatomical underdevelopment of cranial arteries and narrow cerebrospinal passages easily cause cerebral infarction and hydrocephalus following meningeal inflammation due to tuberculosis. These neurological disorders may result in poor prognosis despite of administration of effective anti-tuberculosis medicines. Delay in the diagnosis also makes the treatment difficult in some infants whose tuberculin skin test shows false negative and radiographic manifestation of chest is not clear. During the treatment, systemic and enteric viral infections occur frequently among infants with tuberculosis, and liver functional disorders caused by these infections sometimes disturbs the treatment for tuberculosis. Recurrence of tuberculosis is very rare among infants who complete the full treatment at the age of more than one year. Finally, it is important for the early start of treatment for tuberculosis to recognize both susceptibility to tuberculosis and difficulties in the diagnosis in some infants less than one year.