Profile of Infectious Spondylodiscitis in Rheumatology Consultation at University Teaching Hospital of Kara, Togo

Objectives: The objective is to determine the frequency and the semiological and evolutionary profiles of infectious spondylodiscitis in hospital practice in Kara. Patients and methods: This was a cross-sectional study of a case series of patients with infectious spondylodiscitis, who were admitted to the rheumatology department of Kara University Hospital in North Togo. Results: Among the 3972 examined patients, 86 (33 males and 53 females) patients (2.16%) had infectious spondylodiscitis. The average age of these patients at the onset of the disease was 47.20 years. The average duration of the disease was 11.41 months. Tuberculosis was suspected in 77 of 86 patients (89.53%). The infectious spondylodiscitis most often affected the lumbar (51.04%) and dorsal (21.87%)


Introduction
Osteoarticular infections play a significant role in rheumatology practice. Infectious spondylodiscitis is an infection of the intervertebral disc and adjacent vertebral bodies, rarely affecting the posterior inter-apophyseal joints [1]. Although it is a ubiquitous condition with uneven distribution across the globe [1] [2] [3], more than 90% of cases have been reported in developing countries [4]. According to the World Health Organization, tuberculosis remains the leading cause of infection-related mortality worldwide, affecting about 10 million people in 2019, with 1.2 million deaths mostly in underdeveloped and developing countries [4]. Infectious spondylodiscitis is a real diagnostic and therapeutic emergency. Indeed, these are potentially serious conditions that risk the functional and sometimes vital prognosis of the patient, with long-term chronic disabling sequelae and significant social costs [5] [6]. Many studies have been conducted on infectious spondylodiscitis in Africa [7] [8] [9] [10] and revealed the important part of Pott disease. In Togo, these studies were conducted in the capital city of Lomé [11] [12], and infectious spondylodiscitis accounted for 1.5% of all rheumatic diseases occurring there. The absence of specific data on infectious spondylodiscitis in semi-rural areas in the northern part of Togo was the motivation for this study. It aimed to determine the frequency and the semiological and evolutionary profiles of this condition in the hospital practice in Kara.

Patients and Methods
This was a cross-sectional study conducted on the files of patients suffering from infectious spondylodiscitis. The records of patients with this condition, who were admitted to the rheumatology department of the University Teaching Hospital of Kara (420 km north of Lomé) were analyzed. That department welcomes rheumatic patients from the three northern regions of Togo composed mainly of young and rural population [13]. The study involved patients admitted from April 2013 to June 2020. All patients received imaging of the painful part of the spine and chest X-ray. The positive diagnosis was retained on the radioclinical arguments. No patient performed discovertebral biopsy for technical reasons. The etiological diagnosis was based on microbiological isolation and/or demonstration of characteristic histological lesions (caseous granulomatous inflammation for tuberculosis), epidemiological context of endemicity of Koch's Bacillus in Sub-Saharan Africa [4], and a strong clinical suspicion (existence of another infection, particularly pulmonary tuberculosis, with typical appearance on imaging or a favorable response to antibiotic treatment). Sociodemographic aspects, clinical and paraclinical characteristics, treatment, progress, and follow-up

Sociodemographic Data
Of the 3972 patients admitted during the study period, 86 had infectious spondylodiscitis (2.16%). The female to male sex ratio was 1.60, and the mean age of the patients at the first consultation was 47.20 ± 15.95 years (range, 6 -80 years).

Clinical Data
The pain was the main reason for the patients to visit the hospital. It was mechanical in 54.65% of the cases, inflammatory in 32.56%, and mixed in 12.79%.
The average duration of the evolution of the symptomatology before the rheumatological consultation was 11.41 ± 24.25 months (range, 5 days -44 months).
An alteration of the general state was noted in 80.23% of the cases, with weight loss in 70.93% of them. The lungs (22 cases; 50%), lymph nodes (9 cases; 20.45%), and urogenital tract (4 cases; 9.09%) were the main extraspinal infectious sites associated.

Paraclinical Data
Spondylodiscitis lesions were found on standard radiography in 63.62% of cases, on computed tomography scans in 33.72% of cases, and on magnetic resonance imaging (MRI) in 2.32% of cases. Two cases (2.32%) of spondylitis were confirmed on radiography. The L3 -L4 and L4 -L5 discs were most commonly affected (29.07%). Epiduritis was observed in 15.11% of patients. Ultrasound examination revealed psoas abscess in two patients. Chest radiography was abnormal in 31 cases, with pleurisy observed in 41.94% of the cases ( Table 2).

Therapeutic and Evolutionary Data
The

Discussion
Infectious spondylodiscitis accounted for 2.16% of the cases of rheumatologic diseases at University Teaching Hospital of Kara. This frequency is close to that reported in Lomé, which was 1.5% in 20 years [12]. The average age of the patients was 47.20 years, similar to that reported by other African authors [14] [15] [16]. However, this means age was lower than that reported in the West [17] [18], where patients in their 50s and 60s are more commonly affected. This   to the observations of another study conducted in Lomé [12]. The disease seemed to affect all patients without distinction of sex. Traders and farmers were the most commonly affected professional categories in our study. This was different from the findings of a study conducted in Cotonou, Benin, where office workers were predominantly affected [7]. This difference could be partly explained by the geographical setting of North Togo, which is a semi-rural area, and the low level of education of most of these professions that makes them susceptible to poor hygiene levels. Immunosuppression due to HIV infection modifies the frequency of infectious spondylodiscitis only in areas of high seroprevalence, as it was the third risk factor after underdevelopment and poor hygiene in our study as well as other African studies [7] [12]. Patients often seek consultation at the stage of neuro-orthopedic complications. The delay in consultation and long duration of disease progression are responsible for delayed diagnosis in developing countries [19] [20] [21] as compared to the developed countries [22] [23]. This long delay in progression of the disease is often a reflection of the infectious tuberculosis pathology, which is reputed to be nonspecific with a slow and torpid evolution. The uneven distribution of the infection along the spine is known and has been demonstrated by data in the literature [10] [17] [24]. In our study, signs of infectious spondylodiscitis were revealed on standard radiography in 63.95% of cases. This high rate is related to the long diagnostic delay that favors the appearance of the lesions. The financial and geographical accessibility of modern imaging remains a health challenge in the northern part of Togo, where a low rate of realization of computed tomography and MRI is noted, contrary to that observed in other African and Western countries [18] [25] [26]. If conventional X-rays remain the first-line examination in the investigation of vertebral pain in a febrile context, MRI is the reference examination for the confirmation of spondylodiscitis. Discovertebral abnormalities appear as early as the fifth day, while the changes are not visible on X-rays until after two weeks [27]. The predominance of the tuberculous etiology found in our study confirms the findings of other African authors [8] [10] [12] [28] [29], highlighting the endemicity of the Mycobacterium tuberculosis in the African continent. Pyogenic spondylodiscitis seems to be rare in our environment [7]. However, in Developed countries, they represent the first etiology and are more favored by diabetes, alcoholism and chronic kidney disease [1] [17] [23] [30]. Besides, its incidence seems to be increasing as a result of the increase in spinal instrumentation and surgery and with a higher life expectancy of older patients with chronic debilitating diseases in that countries [31] [32].
The treatment of infectious spondylodiscitis is conservative in most cases, combining targeted antibiotic therapy and immobilization. The indications for surgery are limited, and reserved for the treatment of acute neurological compression due to abscess or bone sequestration [20] [29] [33]. However, regardless Open Journal of Rheumatology and Autoimmune Diseases of the therapeutic protocol, the evolutionary modalities overlap [12] [29] [34]. The outcome was favorable in 75.58% of our patients. The high rate of patients lost to follow-up is partly explained by the low socio-economic level of patients who are unable to honour follow-up assessments and appointments [13]. Although the limitations of this study include evaluation of cases from a single center and the failure of the technical platform, this work had an undeniable epidemiological and management interests for infectious spondylodiscitis in this part of Africa.

Conclusion
Infectious spondylodiscitis is a common reason for patient consultation in North Togo. The high proportion of tuberculous spondylodiscitis cases testifies to the persistence of the endemicity of Koch's bacillus in the African continent, where underdevelopment and insufficient hygiene are the main factors favoring it. The effective management of infectious spondylodiscitis is hindered by the delay in consultation, which is a characteristic of most diseases in this region. However, although the prognosis of the disease is usually favorable with medical treatment, it would be important to conduct further studies to evaluate the socio-economic impact of this condition in our country.