Culture Results From FNAC Specimens Suggestive Of Tuberculous Lymphadenitis

Abstract

The incidence of tuberculosis is high in Kenya and remains a senous health problem. Moreover the appearance of multi drug resistant strains of Mycobacteria tuberculosis (MDR- TB) and the high rate of association with acquired immunodeficiency syndromes (AIDS) Human Immunodeficiency virus (HIV) has increased the need for rapid diagnostic methods. In 1999 there were a total of 60,000 cases of Tuberculosis with a weighted national HIV / prevalence rate in T.B of 40%. FINE NEEDLE ASPIRATION CYTOLOGY(FNAC) IS the main method of diagnosis of Tuberculous lymphadenitis (T.B. Lymphadentitis). Confirmation is done by demonstration of Acid Alcohol Fast Bacilli(AAFBs) with special stains such as Ziehl Neelsen(ZN) from cultured specimens or on direct smear microscopy. The main objective was to establish culture results in cases suggestive of T.B. lymphadenitis on cytology but with a negative Ziehl-Neelsen test (ZN) for Acid Alcohol Fast Bacilli (AAFBs). This was aimed at assessing and ascertaining whether FNAC should be assumed as a test with high rapidity and fast turn around time in diagnosing suspected T. B lymphadenopathy in Kenya. The method of study involved culturing of a residual material using BACTEC CULTURE SYSTEM for such cases. This was a prospective study of cases referred to the fine needle aspiration (FNA) clinic for investigation for the cause for lymphadenopathy. A total of 365 cases were presented in this clinic in a twelve month period between August 2000 and August 2001 out of which 195(54%) were reported to be as a result of tuberculous lymphadenitis by cytology. This compared well with a similar histological study

done at Muhimbili in Tanzania where 173 (67%) cases out of a total of 257 were confirmed histologically as T. B lymphadenitis. The study was conducted at Kenyatta National Hospital. Culturing of the specimens took place in the department of Pathology, at Nairobi Hospital. The study was carried out between months of April and August year 2001. A total of 60 specimens were submitted for culture at The Nairobi Hospital pathology laboratories where 17/60 (i.e. 280/0)specimens were positive for Acid Alcohol Fast Bacilli (AAFBs). There was no significant statistical difference between the performance of cytology and histology in terms of diagnosis. Statistically significant difference was only noted between culture results from FNAC specimens and those of cultured histological specimens. The results reaffirmed cytology as one of the simplest, safe and cheap method of diagnosing T. B. lymphadenitis. The importance of this finding is realized in consideration of increasing cases HIV /AIDS associated tuberculosis. The study also identified the need for increased application and adoption of cytology as diagnostic and screening test for T. B. lymphadenitis especially in peripheral health units where histopathology services are not available due to the limited number of pathologists and lack of appropriate facilities in Kenya. It is also highly recommended that K.N.H being a tertiary medical institution should be equipped with modem culture facilities for Mycobacterium. Currently the hospital does not have any facility for T. B. culture including the conventional ones i.e Lowenstein Jensen media.