Culture Negative Extra Pulmonary Spinal Tuberculosis – a New Challenge

Abstract Introduction Pulmonary Tuberculosis(TB) can be detected by sputum cultures. However, Extra-Pulmonary Spinal Tuberculosis(EPSTB), diagnosis is challenging as it relies on retrieving samples. It is usually discovered in the late stages of presentation due to its slow onset and vague early presentation. Difficulty in detecting Mycobacterium Tuberculosis bacteria from specimens is well documented. Diagnostic imaging is helpful to initiate therapy, but growing incidence of multi-drug resistant TB adds further challenges. Methods A retrospective analysis of cases from the Infectious Disease database with EPSTB between 01/01/2015 to 31/01/2020. Two groups were compared, Culture-Negative TB(CNTB) and Culture-Positive TB(CPTB). Results 31 cases were identified with EPSTB. 68%(n=21) were male. 55%(n=17) were Asian, 19%(n=6) were black and 16%(n=5) were white. 90.4%(n=28) patients presented with isolated EPSTB symptoms. No patient had evidence of HBV/HCV/HIV infections. CPTB Group was 51.6%(n=16) compared to CNTB with 48.4%(n=15) 48%(15) lumbar involvement, 42%(n=13) thoracic and 10%(n=3) cervical. 38.7%(n=12) patients presented with late neurology, equally in both groups. 56% CPTB patients showed signs of vertebral involvement on X-rays compared to 13.3% in CNTB patients. 68.7% CPTB patients had pathological changes seen on CT scan compared to 53.3% of CNTB patients. 81% of CPTB showed positive MRI and 86% in CNTB. Both groups were treated with Anti-TB medications. 83% patients were followed up till the end of the treatment course. 22.5%(n=7) patients had Ultrasound-guided aspiration.29%(n=9) patients required surgery. Conclusion TB continues to be a growing problem in the developed world specially with patients travelling from endemic regions. Thoracolumbar region was most commonly affected(90%). Approximately 50% of cases of extrapulmonary spinal TB were culture negative. Neurological deficit occurred in 40% patients. 30% of patients required surgery. Anti-TB treatment was however effective in all cases. No drug-resistant variants noted. MRI imaging remains the superior diagnostic test in the presence of high CN EPSTB.