Background: The WHO reports an estimate of 10 million cases of tuberculosis per year worldwide1. Australia has one of the lowest rates, with 1,337 cases recorded in 2014 (a rate of 5.7 per 100,000 population)2. 15% of TB present as extra-pulmonary infections, such as lymph nodes, pleural, GI, bones, and skin.
Method: The medical records of a 31 female who presented to our general practice clinic were reviewed and relevant data collected.
Results: A 31-year-old Nepalese female presented with a 3-month history of lower back pain. She described left buttock pain shooting down her leg and worse on weight bearing. There was no trauma or significant past medical history. Clinical examination reproduced the pain on SLR of left leg, with no other examination findings. Initial investigation with CT showed subchondral sclerosis and cortical irregularities of left sacroiliac joint. Blood tests revealed a normal WCC, CRP 15, ESR 86, and negative rheumatological tests (including HLA-B27, RF, anti-CCP, ENA, ANA, and anti-DNA Ab). Further imaging included an MRI (showing minor degenerative changes in left SI joint), NM bone scan (inflammatory process in left sacroiliac joint), and a CT guided biopsy that revealed granulomatous inflammation with culture growing drug-sensitive Mucobaterium tuberculosis.
Discussion: Imaging in spinal TB may prove challenging in early disease. CT may reveal bony destruction (in particular fragmentary type) and also assess for the presence of abscess formation. An MRI is more sensitive in recognising early inflammatory processes and localising disease. However it is unable to differentiate between inflammatory and infective pathology. Radionuclide studies (bone scintigraphy) may assist in evaluating the degree of inflammation. CT-guided biopsy is needed to confirm the diagnosis3.
Implications for practice: It is important for the clinician to be aware of spinal tuberculosis as a differential diagnosis in back pain, and to understand the limitations of radiographic imaging in the diagnosis. References: 1. WHO. Global Tuberculosis Report 2019. Geneva: World Health Organization; 2019. Available at https://apps.who.int/iris/bitstream/handle/10665/329368/9789241565714-eng.pdf [Accessed 29 August 2020) 1. Australian Government Department of Health. Tuberculosis notifications in Australia 2014. Available at https://www1.health.gov.au/internet/main/publishing.nsf/Content/cda-pubs-annlrpt-tbannrep.htm [Accessed 29 August 2020] 2. Rivas-Garcia A, Sarria-Estrada S, Torrents-Odin C, Casas-Gomila L, Franquet E. Imaging findings of Pott's disease. Eur Spine J. 2013;22 Suppl 4(Suppl 4):567-578. doi:10.1007/s00586-012-2333-9