|Year : 2022 | Volume
| Issue : 4 | Page : 203-204
Treatment duration of osteoarticular tuberculosis: How long is optimum?
Department of Orthopaedics, All India Institute of Medical Sciences, New Delhi, India
|Date of Submission||02-May-2022|
|Date of Acceptance||11-May-2022|
|Date of Web Publication||27-Oct-2022|
Professor, Department of Orthopaedics, All India Institute of Medical Sciences, New Delhi 110 029
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Mittal R. Treatment duration of osteoarticular tuberculosis: How long is optimum?. J Clin Sci Res 2022;11:203-4
Tuberculosis (TB), a communicable disease is a major cause of morbidity and mortality globally. Till recently, before the COVID-19 pandemic, TB had been the leading cause of death from a single infectious agent, ranking above human immunodeficiency virus (HIV) infection and acquired immunodeficiency syndrome (AIDS)., Of all the immunocompetent TB patients, extrapulmonary TB (EPTB) constitutes about 15%–20%; but among HIV-coinfected, severely immunosuppressed persons, EPTB accounts for 50% or more of all TB cases., In 2019, EPTB constituted 16% of the 7.5 million notified TB cases. As per the India TB Report 2022, EPTB constituted 28% of the 2,135,830 cases notified.
Osteoarticular TB (OATB) is a paucibacillary disease. While a sputum sample from pulmonary TB patient is teeming with TB bacilli. However, a huge TB psoas abscess with litres of TB pus may reveal only a single TB bacillus. Hence, the demonstration of acid-fast bacilli is very difficult in OATB. The histopathological diagnosis rests on demonstration of caseating epithelioid granulomas in tissue samples. Even with the availability of molecular diagnostic tests, a definitive diagnosis of OATB is often difficult to ascertain.
Pulmonary TB remains the standard model for documenting the outcomes of anti-TB treatment regimens. These treatment outcomes described in relation to pulmonary TB are usually extrapolated to EPTB., Compared to PTB, EPTB requires longer durations of treatment and consensus is lacking regarding the optimum duration of treatment for most forms of EPTB. OATB, a form of EPTB, is characterised by different pathologies and healing patterns as compared to pulmonary TB. There is no consensus regarding the optimum duration of treatment for OATB.
The treatment duration of drug-susceptible pulmonary TB is 6 months and consists of 2 months of the intensive phase of treatment followed by 4 months of continuation phase. However, there is no consensus regarding the optimal duration of treatment in patients with OATB. The American Thoracic Society, the Centers for Disease Control and Prevention and the Infectious Disease Society of America guidelines state that some experts recommend, 9–12 months of treatment for bone, joint TB. The World Health Organization guidelines, recommend 9 months of treatment when bone and joint TB are also present.
In a prospective study, from New Delhi, positron emission tomography-computed tomography (PET-CT) was performed in patients with OATB at the baseline before initiation of anti-TB treatment and then repeated at 6, 12 and 18 months of treatment. It was found that all the patients of OATB had high-uptake lesions at multiple sites besides the index skeletal location. These observations suggest that OATB is a systemic disease and the disease spreads to the skeletal location through haematogenous route from some other location. These other sites of high uptake included regional lymph nodes, mediastinal lymph nodes, lungs, vertebrae and soft-tissue abscesses. The median (interquartile range [IQR]) time (days) to completer response to treatment at skeletal lesions was 591 (417–661) and that of extraskeletal lesions was (IQR 299–633). Most of the soft-tissue lesions in extraskeletal sites healed at the end of 6 months of treatment. However, the skeletal sites still showed increased uptake indicating the activity of disease at the end of 6 months. Contrary to standard recommendations, only 30% showed complete response at 12 months. Complete response was present in 80% at the end of 18 months of treatment. PET-CT indicates the metabolic activity at the site of lesion. An increased uptake indicates an active lesion and decreased uptake indicates the healing of disease. This is an objective, direct and reproducible evidence of disease activity and is independent of any other factor. Hence, the presence or absence of increased uptake on PET scan indicates active or healed status of the disease.
Conventionally, orthopaedicians regard the optimum duration of treatment for OATB to be 12–18 months. In the absence of any hard evidence of healing of OATB, a healed status is characterised by improvement of general symptoms, resolution of local pain and restoration of local function. This is supported by decrease in inflammatory markers and replacement of local osteoporosis by osteosclerosis. There is a huge time lag between radiographic healing and subjective improvement of general health. Most of the guidelines for treatment are formulated have been arguing for reduction in the duration of treatment. Orthopaedicians, on the basis of anecdotal evidence and expert opinion often feel that the relapse rate is high when short-course treatment was administered. Both these arguments lack hard published evidence.
This prospective study is the first of its kind to investigate the healing of OATB at the molecular level. Previous studies have used magnetic resonance imaging (MRI) to document healing, but radiographic healing as documented by MRI lags behind the actual healing. This study provides evidence that skeletal lesions do not heal even at 12 months in the majority of cases. Hence, a short-course of anti-TB treatment of 6 months is not adequate for skeletal lesions. Most of the skeletal lesions heal by 18 months. Hence, in OATB, 18-month duration of anti-TB treatment appears appropriate.
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