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- radiology (diagnostics)
- infections
- paediatrics (drugs and medicines)
- TB and other respiratory infections
- paediatrics
Description
A 10-year-old, HIV-negative boy presented with significant weight loss, mild left hip arthralgia, a chronic nasal bridge ulcer and distal tracheal compression on chest X-ray. Biopsy of the nasal bridge ulcer was negative, and bronchoscopy was normal, although the Xpert MTB/RIF was trace positive. The child was started on anti-tuberculosis (TB) treatment based on constitutional symptoms, reactive Mantoux (20 mm) and the Xpert MTB/RIF result. Rheumatology and the immunology work-up was negative. Due to the inconclusive testing and ongoing symptoms which included fever, weight loss and persistent mild left hip arthralgia, F-18 fluorodeoxyglucose (FDG) Positron emission tomography (PET) and computed tomography (CT) (PET–CT) was performed to identify either intrathoracic or extrathoracic biopsy sites (preferably lymph nodes) to confirm a diagnosis of TB. The scan identified abscess formation in both psoas muscles with the activity extending from the left psoas muscle into the left gluteus maximus muscle. It also identified intense uptake in L1/L2 spondylodiscitis, and multilevel destructive changes in the vertebral bodies of L1, L2, L4, L5 and S1 with extension into the spinal canal at the lower two levels (figure 1). MRI of the lumbosacral spine confirmed the multifocal vertebral lesions (L1, L2, L5, S1) demonstrating signal alteration and height loss with relative preservation of the intervertebral discs, as well as predominantly prevertebral abscesses and subligamentous spread, typical of tuberculous spondylitis. There were also some posterior impressions on the thecal sac at S1 from the paraspinal abscess. Extensive soft tissue abscesses were present, involving the psoas muscle on the left and bilaterally the iliacus muscles, with deep extensions into the paravertebral muscles, extending subcutaneously on the left (figure 2).
Thick pus was aspirated from the psoas abscess under ultrasound guidance. This confirmed drug-sensitive TB both on Xpert MTB/RIF and on culture.
TB is the leading cause of death due to a single infectious agent globally with childhood TB accounting for 14% of the overall TB mortality worldwide. The difficulty in confirming TB in children microbiologically can result in delays in starting TB and also lead to more severe extensive disease.
F-18 FDG PET/CT is emerging as a valuable imaging tool in the management of complicated TB.1 While most of this benefit is supported by research in adults, there is growing recognition of PET/CTs utility in children.2 Advances in modern PET/CT scanner technology (higher sensitivity PET detectors, iterative CT reconstruction techniques) also continue to make such scanning safer in terms of administered radiation dose, to the advantage of paediatric patients.3
F-18 FDG PET/CT is highly sensitive for active pulmonary and extrapulmonary TB infection.1 4 The three-dimensional nature of PET/CT imaging (which can either be confined to a region of interest or include the whole body) enables the detection, accurate localisation and evaluation for extent of TB lesions.
In our patient, the advantage of using FDG PET/CT was the demonstration of disseminated TB and the identification of an abscess which could be aspirated to confirm the diagnosis. The findings of the FDG PET/CT correlated with the findings on MRI.
Learning points
Challenges in diagnosing tuberculosis (TB) may result in delays in starting anti-TB treatment.
F-18 fluorodeoxyglucose (FDG) PET/CT is highly sensitive for active pulmonary and extrapulmonary TB infection.
FDG PET–CT can determine areas that can be either be biopsy or aspirated for diagnosis and microbiological conformation.
Ethics statements
Patient consent for publication
Acknowledgments
Dr Alex Doruyter for his advice and help with manuscript.
Footnotes
Contributors PG and HR were involved with the clinical management of the patient. SA and CB were involved with the imaging of the patient. All were involved in creating the manuscript.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Case reports provide a valuable learning resource for the scientific community and can indicate areas of interest for future research. They should not be used in isolation to guide treatment choices or public health policy.
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.