Tuberculous lymphadenitis in Singapore.

An analysis of patients diagnosed as having tuberculous lymphadenitis (the second commonest form of tuberculosis after respiratory tuberculosis) in 1980, was carried out to ascertain the pattern of disease and methods of diagnosis. Of 114 cases so notified, 97 were available for this purpose. Diagnosis was on lymph node biopsy with histological examination and/or bacteriological culture confirmation. Patients with tuberculous lymphadenitis tended to be young (more than 60% below 31 years old), and to have cervical involvement (88.6% of cases). A female preponderance (as in other studies) and a disproportionate number of Indians and Malays (thrice and twice that expected on the basis of their ethnic proportion of the Singapore population) were noted. Only 25 out of 97 biopsied glands were sent for mycobacterial culture by the surgeons and 16 grew niacin positive Mycobacteria tuberculosis. This 64% culture-positive rate is more sensitive and specific than the histological demonstration of acid-fast bacilli (13.4%) in the diagnosis. It must be stressed that the pathologist can only report a picture consistent with or supportive of a diagnosis of tuberculosis and be more confident if acid-fast bacilli are seen microscopically. The diagnosis cannot be absolute except on a positive culture which also identifies typical or atypical mycobacteria and allows drug sensitivity testing. Surgeons removing lymph nodes in patients suspected to have tuberculous lymphadenitis must send these to both the bacteriologist and pathologist, the tissue to the former not being suspended in formalin but saline.