Reply to: Imaging in Musculoskeletal TB by Spalkit S Et Al.

Dear Sir,

I read with interest the excellent and exhaustive article describing imaging in musculoskeletal tuberculosis (TB) by Spalkit et al.[1] I would like to add a few more points with respect to musculoskeletal TB. I would like to re-emphasize some additional factors that predispose to unusual sites and imaging patterns of TB, such as tumor necrosis factor-α (TNF-α) inhibitors use for immune-mediated inflammatory disease, malnutrition and low body mass index, smoking, and alcohol.[2] Apart from the classical and common extradural tuberculous spondylodiskitis and less common intramedullary TB, very rarely, an extramedullary intradural tubercular granuloma may also be seen.[2] Multifocal skeletal TB, defined by the presence of osteoarticular lesions at  ≥2 locations, accounts for less than 5% of the cases of skeletal TB in endemic countries such as India. It can present with systemic symptoms like fever, anorexia, and weight loss, and may mimic metastasis or hematological malignancy, especially in the absence of lung lesions.[2] Anterior pattern of spinal TB with subligamentous collection and periosteal stripping makes the avascular vertebra more vulnerable to infection. Ischemia and pressure from the subligamentous collection produce scalloping of the anterolateral surface of the vertebral bodies (“gouge defect”) and may mimic bone tumor, metastatic lymph nodes, or even an aorta aneurysm.[3] Spinal TB may rarely cause reactive sclerosis resulting in an “ivory” vertebra.[3] Definite “claw sign” on diffusion weighted magnetic resonance imaging (MRI) signifies very high likelihood of Modic type 1 degenerative endplate changes (97–100%), whereas a pattern of diffusely increased diffusion signal (negative claw sign) signifies infection in 93 to 100% of patients.[4] Whole-body fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) imaging is very useful in evaluating spine TB and the extent of involvement and is considered a complementary tool to the imaging gold standard, MRI.[3] [5] As radiographic progression of bone destruction may continue for up to 14 months postinitiation of antituberculous therapy, it should not be considered treatment failure. Recovery of vertebral body height is not seen earlier than 15 months after starting treatment.[3] [6]

Layered periosteal reaction may be seen in pediatric patients with TB osteomyelitis/arthritis, unlike in adults. Epiphyseal hyperemia in pediatric patients may result in advanced maturity of the epiphyseal plate with limb shortening.[6] Poncet's arthritis, a commonly under-recognized rare form of aseptic reactive arthritis, occurs in patients with extrapulmonary TB, especially those with erythema nodosum. They usually present with acute polyarthritis (in contrast to monoarticular involvement in TB arthritis), which subsides within a few weeks of medical treatment, with no residual joint destruction.[6] It is also important to be aware of three types of TB of the shoulder: (1) dry type, or caries sicca; (2) fulminating type, or caries exudate, associated with cold abscess or sinus formation; or (3) mobile type, where a passive range of motion is preserved, while there is variable restriction on active movement.[7] Finally, classical as well as Shanmugasundaram radiological classification of TB of the hip based on joint destruction, stability, morphology, and anatomical relation is quite useful for radiological staging.[8]

 

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Conflict of interest

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• References

• 1 Spalkit S, Goyal A, Gamanagatti S, Kandasamy D, Sharma R. Imaging in musculoskeletal TB. Indographics 2024; 3 (02) 100-120
• 2 Rana A, Krishnan V, Aggarwal A. Unusual patterns of tuberculosis on cross-sectional imaging: a pictorial review. Egypt J Radiol Nucl Med 2022; 53: 190
• 3 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): 567-578
• 4 Patel KB, Poplawski MM, Pawha PS, Naidich TP, Tanenbaum LN. Diffusion-weighted MRI “claw sign” improves differentiation of infectious from degenerative modic type 1 signal changes of the spine. AJNR Am J Neuroradiol 2014; 35 (08) 1647-1652
• 5 Sampath S, Basumani P, Kothandaraman A, Ramakrishnan R. Detection of spinal tuberculosis by F-18 FDG PET/CT as a cause of unusual referred pain in the right upper quadrant of abdomen. World J Nucl Med 2022; 21 (01) 69-72
• 6 Mahomed N, Kilborn T, Smit EJ. et al. Tuberculosis revisted: classic imaging findings in childhood. Pediatr Radiol 2023; 53 (09) 1799-1828
• 7 Darraj M. Delayed presentation of shoulder tuberculosis. Case Rep Infect Dis 2018; 2018: 8591075
• 8 Moon MS, Kim SS, Lee SR, Moon YW, Moon JL, Moon SI. Tuberculosis of hip in children: a retrospective analysis. Indian J Orthop 2012; 46 (02) 191-199

Publikationsverlauf

Artikel online veröffentlicht:
30. Dezember 2024