Correlation between PCR and histopathology in TB spine

Abstract

Introduction: Tuberculosis (Tb) is an infectious disease with enormous mortality and morbidity. In India alone about 33 million people are suffering from Mycobacterium tuberculosis and around 3 million are suffering from extra-pulmonary tuberculosis. It is a major burden on health care agency, hence the importance for rapid and accurate diagnosis cannot be ignored. Earlier diagnosis was based on detection of AFB on ZN stains which offers low sensitivity (requires 10^4 bacilli/ml for positive result), Mycobacterium culture is the standard method but due to its long incubation time affects treatment and long term outcome. Histopathological examination provides good information regarding the tissue and sample material but with limited capacity of its specificity the diagnosis and treatment is doubtful, i.e. epithelioid granuloma and caseating necrosis can occur in disease other than Tb. The acknowledgment of ATT therapy was widely used previously to confirm the diagnosis. With the advent of nucleic acid amplification tests there was a major advance in the diagnosis of tuberculosis, by using amplification systems, nucleic acid sequences unique to Mycobacterium tuberculosis can be detected directly in clinical specimen with better accuracy than AFB staining and at greater speed than culture and more specific than histopathology. Method: The Samples were collected under strict aseptic precautions in the operation theatre under the fluoroscopic guidance from the affected vertebrae using jamshidi needle. The collected sample were sent for PCR for Tb, ZN staining and Histopathological examination. Results: Histopathology was found positive in 18 patients and PCR was found positive in 25 patients. Both were found positive in 15 patients