The efficacy of diagnostic battery in Pott's disease: A prospective study

BACKGROUND: The diagnosis of Pott's disease is mostly based on clinicoradiological observations substantiated by the bacterial culture, staining and histopathology. Since, no single technique is enough to conclude Pott's disease in diagnosis, the present study was undertaken to correlate the clinicoradiological, microbiological, histopathological and molecular method to evaluate the effectiveness in diagnosis of Pott's disease. MATERIALS AND METHODS: 62 clinicoradiologically suspected cases of Pott's disease were included in this study. The specimens for diagnostic work up were collected either during surgery or by computed tomography guided fine needle aspiration. All these specimens were tested for tuberculosis (TB) through Ziehl-Neelsen (ZN) microscopy, BACTEC culture, histopathology and polymerase chain reaction (PCR). The final diagnosis was established by the results of performed tests and clinicoradiological improvement of cases at the end of 6 months on anti tubercular treatment. RESULTS: Out of 62 cases, 7 were excluded from this study as these were turned out to be neoplastic lesions on histopathology. Amongst remaining 55 cases, the TB was diagnosed in 39 (71%) on histopathology, 37 (67.5%) on PCR, 27 (49%) on BACTEC culture and 20 (36.3%) on ZN microscopy. Ultimately 45 cases were tested as positive and 10 were detected as negative for TB in combination of ZN microscopy, BACTEC culture and histopathology. PCR was positive in 37 of 45 cases and 10/55 cases remained negative. On clinical analysis of these 10 cases, it was noted that these were cases of relapse/poor compliance. The combination of PCR and histopathology was also shown positive for TB in 45 cases. Hence, the PCR showed a fair positive agreement (Κ(c) = 0.63) against the combined results of all performed traditional methods. CONCLUSIONS: The combination of PCR and histopathology is a rapid and efficient tool for diagnosis of Pott's disease.