Primary site of involvement in congenital TB:

Ans. (b) Liver(Ref: Nelson 19 ed Chap 212)In congenital TB, primary organ involved is liver.Congenital tuberculosis is rare because the most common result of female genital tract tuberculosis is infertility.Congenital transmission usually occurs from a lesion in the placenta through the umbilical vein.Primary infection in the mother just before or during pregnancy is more likely to cause congenital infection than is reactivation of a previous infection.The tubercle bacilli first reach the fetal liver, where a primary focus with periportal lymph node involvement may occur.Organisms pass through the liver into the main fetal circulation and infect many organs.