Evaluation of the validity of high serum antistreptolysin o titre only, as an indication for tonsillectomy.

Abstract

Serum Antistreptolysin O (ASO) titre is raised when there is infection of any organ of the body, by Group A beta haemolytic streptococci (GABHS), Group C or Group G streptococci [1]. Increased serum ASO titre should not be the only deciding criterion for tonsillectomy if GABHS is not present in the palatine tonsils. In this study, we evaluate the rationality of performing tonsillectomy in raised serum ASO titre only, in absence of GABHS in palatine tonsil. The study was designed as a prospective cohort study in which the main out come measure is to find out: The main outcome measure is to find out whether only the raised serum ASO titre is to be considered to perform tonsillectomy or not. Fifty consecutive patients (both children and adults) clinically diagnosed to have chronic tonsillitis were included in this prospective cohort study. Throat swab culture, tonsilar core tissue culture and Serum ASO titre tests were performed in all the patients. The results showed that out of the 50 patients 45 had raised ASO titre and 5 patients had normal ASO titre. GABHS was found in 5 cases (10%) in throat swab culture and 8 cases (16%) in FNA of tonsil core culture. The sensitivity of throat swab culture as compared to FNA Tonsil core culture was 62.5% and positive predictive value was 100%. The sensitivity of ASO titre as compared to core culture was 100% and positive predictive value was 17.8%. Specificity was only 12%. From the results of this study, it is evident that FNA culture of the tonsil core is a valid and a reliable test for the diagnosis of bacterial micro flora in recurrent tonsillitis. One should perform throat swab culture and FNA culture from tonsil core along with ASO titre before doing tonsillectomy in absence of any other indications. Identifying GABHS in the tonsil by FNA test and/or in the throat swab culture along with high serum ASO titre may be one of the ideal indications for tonsillectomy.