Background: Tuberculosis (TB) is an emerging health problem despite the advances in the methods of diagnosis and treatment. The resurgence of tuberculous spondilodiscitis (TBSD) or Pott’s disease can be expected to be associated with a concomitant increase in the incidence of extra-pulmonary TB. Aim: To describe the clinical features, imaging findings, and laboratory diagnosis in a group of patients with TBSD. Materials and Methods: From January 1 st 2000 to December 31 st 2010, we retrospectively reviewed 22 cases of spinal TB. Only those with positive culture results and/or characteristic clinical and pathological findings were enrolled. Demographic data, comorbilities, clinical manifestations, time up to the definitive diagnosis, outcome and sequelae were considered. Results : During the study period, 22 patients were diagnosed with TBSD; 14 were men and 8 women with a median of age of 34 years at the time of diagnosis. The median duration of symptoms before the TBSD diagnosis was 120 days (range 30 to 360 days). At the time of diagnosis, fever and back pain were the most common clinical symptoms; 7 patients (32%) had fever and 21 (95%) had spinal pain; eleven patients (50%) had constitutional symptoms; 6 (27%) had respiratory symptoms and 3 (13.6%) had neurological manifestations. Magnetic resonance imaging (MRI) was performed in 9 (40%) cases, computed tomography (CT) in 7 patients (32%), and abdominal ultrasound in 6 cases (27%). The lumbar spine was the most commonly involved site (14 patients, 64%); thoracic spine was involved in 2 patients (9%); dorsolumbar spine was compromised in 4 cases (18%). Cervical spine was only involved in one patient (4.5%) and the last patient (4.5%) presents a global spinal involvement (cervical-thoracic and lumbar spine). Conclusion: Insidious clinical course and ambiguous manifestations of TBSD often delay the accuracy of diagnosis. Spinal TB should be included in the differential diagnosis of patients with prolonged back pain and fever.
Keywords: Mycobacterium tuberculosis , spondilodiscitis, tuberculosis
In 1779, Percival Pott published the first description of the spinal tuberculosis (SP) named as Pott’s disease.  Any organ system may be affected by M. tuberculosis, pulmonary tuberculosis (TB) is the most clinical manifestation including 80% of all the cases.  Bone and joint TB account approximately 15% to 38% of extrapulmonary form of the disease and 1% to 5% of all the cases of TB. , Spinal TB is the most frequent of the musculoscheletical form of the disease and can affect any segment of the lower thoracic and the lumbar vertebrae. Usually spinal TB has an insidious clinical evolution with a mild clinical symptoms and a diagnosis delay.  The optimal treatment of spinal TB remains controversial particularly in the topics related with the duration of the antituberculous treatment and the necessity of surgical treatment. We included a retrospective study of 22 patients with diagnosis of tuberculous spondilodiscitis in a reference hospital of Buenos Aires, Argentina.
From January 1 st 2000 to December 31 st 2010 we reviewed introspectively 22 cases of spinal TB. Diagnosis of spinal TB was confirmed when: 1) M. tuberculosis was isolated from the specimens obtained of the spinal tissue, paraspinal abscess, or psoas abscesses; 2) histopathological findings of caseating granulomatous inflammation with positive acid-fast bacilli (AFB) in the biopsy smears associated with a good clinical response to antituberculous therapy; 3) also, when M. tuberculosis was isolated of other concomitant extravertebral focus plus the presence of clinical and radiological findings compatible with spinal TB. Demographics characteristics, clinical history, comorbilities including HIV infection, clinical manifestations, time up to the definitive diagnosis, outcome, and sequelae were also considered. All data were analyzed with Microsoft ® Office Excel 2003. Continuous variables were compared using Student’s test and the association levels were analyzed with x2 or Fisher’s exact tests. A P value <0.05 was considered to be statistically significant.
During this 11-years period, 22 patients were diagnosed with TBSD; 14 were men and 8 women with a median of age of 34 years at the time of diagnosis (only 4 patients were older than 55 years). Six patients were Bolivian and 1 was Peruvian; the rest were Argentines.
Ten patients (45%) had no specific underlying diseases; 2 patients (9%) had a previous history of pulmonary TB and 1 (4.5%) had contact with a patient with TB. Nine patients (41%) had comorbidities; 2 (9%) were alcoholists; 1 (4.5%) had an autoimmune hemolytic anemia and received long-term corticosteroid therapy before the diagnosis of spinal TB and 6 (27%) were seropositive for human immunodeficiency virus (HIV). In these patients, the median of CD4 T cell count was 74 cells/μL (range: 3 to 221 cells/μL). Also, the median duration of symptoms before the SDTB diagnosis was 120 days (range 30 to 360 days). There was no significant correlations between the median of time before the diagnosis and the age at the time of the clinical evaluation (r = 0.39).
At the time of diagnosis, fever and back pain were the most common clinical symptoms; 7 patients (31.9%) had fever and 21 (95%) had spinal pain; thoracic or lumbar pain was present in 21 patients (3 with dorsal pain, 13 with lumbar pain and 5 with dorsolumbar pain). Eleven patients (50%) had constitutional symptoms; 6 (27.3%) had respiratory symptoms and 3 (13.6%) had neurological manifestations.
Magnetic resonance imaging (MRI) was the most frequent imaging modality used in the evaluation of spinal lesions. MRI was performed in 9 (40.1%) cases, computed tomography (CT) in 7 patients (31.9%), and abdominal ultrasound in 6 cases (27.3%). The lumbar spine was the most commonly involved site (14 patients, 64%); thoracic spine was involved in 2 patients (9%); dorsolumbar spine was compromised in 4 cases (18%). Cervical spine was only involved in one patient (4.5%) and the last patient (4.5%) presented a global spinal involvement (cervical-thoracic and lumbar spine). The number of vertebral bodies involved ranged from 1 to 7; 8 patients (36.4%) had ≥3 vertebral bodies involvement. Additionally, 5 patients (22.7%) had paraspinal abscesses, 2 patients (9.1%) had epidural abscesses, 10 patients (45.4%) had psoas abscesses and 1 patient (4.6%) had a renal abscess.
The majority of patients (19, 86.4%) had confirmed diagnosis of TB for the presence of acid-fast bacilli on Ziehl-Neelsen’s stain or culture in different clinical specimens or by the visualization of granulomas in biopsy smears. In 3 cases (13.6%), the epidemiological data, clinical evolution, and the response to antituberculous therapy suggested the diagnosis of TB. M. tuberculosis was identify in sputum smears of 4 patients (18.2%), in cerebrospinal fluid in 2 cases (9.1%), in the paravertebral abscesses of the epidural space aspiration in 3 (13.6%), and in 5 cases (22.7%) of psoas abscesses and ganglionar aspiration, respectively. Eight patients (36.4%) had granulomas with caseum in biopsy smears. In this series, in 68% of cases with confirmed SDTB the diagnosis was made without CT-guided needle vertebral biopsy or CT-guided surgical drainage.
Treatment and Outcomes
Of the 22 M. tuberculosis isolates from the different clinical specimens, 17 (77.3%) were susceptible to the currently first-line antituberculous drugs, including isoniazid (I), rifampicin (R), ethambutol, pyrazinamide, and streptomycin. Treatment strategies were based on the guidelines of the Argentina National TB Program; the therapeutic regimen consisted of a combination of four drugs including I and R for 2 months and after, I and R until complete 12 months of therapy. Five patients had diagnosis of multidrug resistant TB and received alternative anti-tuberculous schemes including second-line drugs. The mortality rate was 4.6% with only one death in this series.
Although M. tuberculosis is an uncommon pathogen in western countries, it is still common in the developing world. TB of the spine accounts for 50% of skeletal TB , and 1% to 5% of all TB cases. ,, An important finding of our study is that 31.8% of patients were natives of other countries, different of Argentina, in which TB is an endemic disease.
Backache and fever were the most common symptoms of tuberculous spondilodiscitis that has been reported as a reactivation of pulmonary of other extravertebral tuberculous focus.  Similar to other studies, in our series, back pain was the most commonly presented symptom at the time of TBSD diagnosis,  followed by fever and constitutional symptoms as weight loss and night sweats. Additionally, a great range of duration symptoms has been described in patients with TBSD.  In our series, the median of time before the confirmed diagnosis was 120 days, probably due to the insidious clinical course of the disease, the non-specific clinical manifestations and the less clinical suspected. All these characteristics contribute to the delay in the diagnosis and increased the risk of neurological sequelae.
In a different series, a great number of patients had manifestations of pulmonary or extravertebral TB.  In our study, half of patients (11 of 22) presented with other active focus of extravertebral TB, especially, lung and nodal disesase. This percentage is high in comparison with other studies,  but is similar with the description of Gómez Rodriguez et al.  that included 76 cases of spondilodiscitis with 48% of active extraspinal TB. Weng et al.  published a 32% of association between spinal and pulmonary TB.
TBSD generally involve the thoracic and lumbar vertebrae; MRI is the most useful imaging technique to evaluate and detect the spinal TB lesions due to the high sensitivity and specificity (96% and 94%, respectively).  In our series, the lumbar and the thoracic spine were the most frequently affected in 50% and 22.7% of cases, respectively.
Another interesting finding of our study is that abdominal ultrasound showed unilateral or bilateral psoas abscesses in 4 patients (18.2%); in these cases, the ultrasonographic guided fine-neddle drainage was positive for acid-fast bacilli on Ziehl-Neelsen stain and culture and confirmed the etiological diagnosis.
Two patients (9.1%) of this series presented with clinical and radiological signs of epidural abcesses. In these cases, MRI scan showed thick epidural soft tissue compressing the spinal cord. Histopathological analysis revealed abscesses due to M. tuberculosis. Both patients responded well to the spinal descompression followed by the antituberculous therapy.
TBSD is a severe form of extrapulmonary TB associated with an insidious clinical course and, generally, with a delay to achieve the definitive diagnosis. Spinal TB should be included in the differential diagnosis of patients with prolonged back pain and fever. Early diagnosis followed by specific antituberculous therapy can reduce the morbidity and the sequelae in this kind of patients.
Source of Support: None, Conflict of Interest: None