Tuberculosis of the extra-axial skeleton in paediatric patients

Abstract

ABSTRACT BACKGROUND: Musculoskeletal tuberculosis (MSK TB) is a disease entity that often mimics other orthopaedic conditions in its radiographic and clinical presentation, which can delay diagnosis and treatment. The purpose of this study is to examine the clinical and radiographic presentation as well as the accuracy of various diagnostic tests, treatment, complications and outcome in paediatric patients diagnosed with MSK TB. We aim to provide insight into typical presenting features in order to expedite diagnosis in this perplexing disease. METHODS: We retrospectively reviewed 77 consecutive patients with extra-axial MSK TB treated at our institution over a ten-year period from 2008 to 2018. We collected data on initial clinical presentation, laboratory values, radiographic findings, diagnostic testing, treatment and outcomes. We performed quantitative and qualitative analysis to look for patterns in presentation that can help with diagnosis and factors affecting the clinical outcomes. RESULTS: The most common clinical presentation was pain of the affected limb. Constitutional symptoms were uncommon. Our patients presented with thrombocytosis and anaemia, but normal white cell counts. Inflammatory markers were mildly elevated. Of diagnostic tests employed, the Mantoux skin test yielded the most positive results (70%) followed by tissue PCR (53%). The hip was most frequently involved, followed by the knee and elbow. Most patients presented with normal appearing X-rays. We had a medical compliance rate of 94% with all patients followed up to completion of treatment having resolution of active disease. Thirty-nine per cent of our patients had residual joint stiffness or deformity following completion of treatment, ranging from ankylosis to mildly decreased joint range. CONCLUSION: Patients with MSK TB usually present with non-specific symptoms and signs, and a high index of suspicion should be maintained in endemic areas. Typical haematological findings are an elevated ESR and CRP accompanied by anaemia and thrombocytosis. Radiographs at presentation are non-specific in more than 50% of patients. A combination of diagnostic modalities should be employed as no single test is 100% sensitive or specific. Compliance with medical treatment reliably leads to resolution of the disease. Residual joint pathology is common and needs to be addressed secondarily. Level of evidence: Level 4 Keywords: musculoskeletal tuberculosis, paediatric tuberculosis, joints, anti-tuberculosis treatment, deformity, GeneXpert