Frequency of tuberculous cervical lymphadenitis detection at a single laboratory in islamabad.

Objective: To determine the frequency of tuberculous cervical lymphadenitis and to evaluate the diagnostic efficacy of microscopy and conventional Lowenstein Jensen (LJ) culture technique in the diagnosis of cervical lymphadenitis caused by M. tuberculosis (MTB) Study Design: A descriptive, cross-sectional study. Place and Duration of the Study: Department of Mycobacteriology, Public Health Laboratories Division, National Institute of Health, Islamabad, from January 2003 to December 2004.

Patients And Methods: A total of 220 patients from Pakistan Institute of Medical Sciences (PIMS), Islamabad, Federal Government Services Hospital (FGSH), Islamabad and Rawalpindi General Hospital (RGH), Rawalpindi, presenting with enlarged cervical lymph nodes (for at least six months), pain/ weight loss and low grade fever were studied for the presence of MTB from 142 lymph node biopsies, 60 FNA samples and 18 discharge fluids/swabs. All the samples were examined at NIH by ZN staining smear and culture on conventional LJ medium as well as on Bactec 12B medium using Bactec 460 TB system. The drug susceptibility testing of the isolates was performed on Bactec 460 TB system. NAP test on Bactec 460-TB system, Accuprobe and biochemical tests were employed to identify the mycobacterial isolates.

Results: M. tuberculosis accounted for 173 out of 220 cases of cervical lymphadenopathy. Maximum incidence was found to be in the age group 10-30 years with male to female ratio of 1:1.7. Discharge sinuses and abscess formation were uncommon. Biopsy tissue samples gave the maximum yield of positive mycobacterial cultures as all 142 biopsy samples being positive while only 50% (30/60) of FNA and 5.5% (1/18) of discharge fluids/swabs were positive. All the isolates were identified as M. tuberculosis. No atypical mycobacteria were recovered from the samples examined. All isolates were found to be susceptible to first line anti-tuberculous drugs i.e. Streptomycin, Isoniazid, Rifampicin and Ethambutol (SIRE).

Conclusion: Tuberculosis was the major cause of cervical lymphadenopathy in the referral area. Culture of the biopsy tissue from the affected lymph nodes is a method of choice for laboratory diagnosis of tuberculous cervical lymphadenopathy.