[Clinical characteristics in non-symptomatic infants with tuberculosis whose diagnostic clue was regular tuberculin skin test prior to BCG vaccination].
OBJECTIVE
Tuberculin skin test (TST) is a useful tool to find non-symptomatic infants with tuberculosis. In 2005, Japanese government starts direct BCG vaccination without prior TST, and we may miss one of the chances to find the above patients. In this study, we tried to find if there is any clinical examination to find non-symptomatic infants with tuberculosis instead of regular TST.


METHODS
We found out 20 non-symptomatic infants with tuberculosis among 131 infants who referred to our clinic because of positive TST prior to BCG vaccination from 1996 to 2003. We examined the data of gastric aspirate examination for Mycobacterium tuberculosis, complete blood counts, and serum chemistries in the 20 infants with tuberculosis. We also tried to find out the source of tuberculosis of these patients by the contact investigation.


RESULTS
Induration of TST among 20 non-symptomatic infants with tuberculosis were 7 to 26 (median, 13.5) mm. Mycobacterium tuberculosis from gastric aspirates was positive in 13 infants (65%). The level of blood hemoglobin was more than 11 g/dl in all infants. The white blood cell count was increased in 6 infants (30%), and exaggerated lymphocyte predominance was recognized in 8 infants (40%). Serum CRP was normal, or subtly increased. Serum GOT (AST) was increased in 15 infants (75%), though the reason was unknown. Serum albumin was normal in all the infants. In the contact investigation, suspected sources were found in 11 infants (55%), and 6 out of 11 sources (55%) were their mothers. Nine sources did not belong to the risk groups for tuberculosis except two mothers coming from tuberculosis epidemic countries.


CONCLUSIONS
In 20 non-symptomatic infants with tuberculosis, examination of gastric aspirate for Mycobacterium tuberculosis, TST, and chest imaging were useful tools to diagnose tuberculosis. However, these examinations are not done in non-symptomatic infants. Eleven family members who might infect the infants were found by the contact investigations, and none of them realized that they have tuberculosis. Our study suggests that there is no realistic clue to find non-symptomatic infants with tuberculosis instead of regular TST, and that the control of infant's tuberculosis still depends on the examination of close contacts of sporadic adult patients with tuberculosis.
Kondo
Shinya
S
Department of Pediatrics, Tama-hokubu Medical Center, 1-7-1, Aoba-cho, Higashi-murayama-shi, Tokyo 189-8511 Japan. shinya_kondo@tamahoku-hp.jp
Miyagawa
Tomoo
T
D001500:BCG Vaccine; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D014374:Tuberculin Test; D014376:Tuberculosis / Q000175:diagnosis*; D014611:Vaccination
D001500:BCG Vaccine