Teaching Case

30-year-old male who recently immigrated from Africa presents with progressively worsening upper back pain for the past 2 years that now radiates to his right flank. He also has been experiencing night sweats, anorexia, and weight loss recently. He denies cough or shortness of breath.

CT abdomen and pelvis with contrast revealed an enhancing fluid collection in the right psoas muscle (Figure 1) and right gluteal musculature (Figure 2). It also showed a large pre-sacral fluid collection (Figure 3). Additional findings include well-corticated osteolytic lesions of the thoracolumbar spine (Figure 4).

CT chest with contrast showed kyphosis with a T8 epicentre secondary to anterior wedging of thoracic vertebrae (Figure 5).

MRI lumbar and thoracic spine demonstrated extensive multisegment inflammatory process involving essentially the entire thoracolumbar spine with extensive multisegment prevertebral and paraspinal fluid collection on STIR sequence (Figure 6). It also showed a prevertebral fluid collection largest in the sacral region on STIR sequence (Figure 7).

According to the World Health Organization, an estimated 10.6 million people became ill with tuberculosis (TB) globally in 2021, equivalent to 134 cases per 100,000 people [1]. 1.6 million died from the disease, making it the second most common infectious cause of death behind Covid-19 [1]. An estimated 3% of TB cases are extrapulmonary, with around 5% of those cases being spinal TB, also known as Pott disease [2]. This means there are likely around 16,000 cases of spinal TB every year.

Spinal TB is usually the result of haematogenous seeding to the paravertebral vessels from a primary site, such as the lungs [3]. It can present in a variety of ways depending on disease severity, with symptoms such as fever, fatigue, back pain, vertebral deformities such as kyphosis, and neurologic deficits [3]. For diagnosis, evidence of TB through various methods such as skin-testing or biopsy coupled with imaging findings is the gold standard [4].

Plain films have a low sensitivity in early stages but can show vertebral body destruction and spinal deformity in later stages. Chest x-ray is also important to look for the presence of pulmonary disease [3]. CT can show vertebral body destruction and osteolytic lesions at earlier stages than plain films [5]. MRI is the most sensitive form of imaging as it can easily detect structural abnormalities as well suspicious soft tissue findings such as oedema and spinal abscess [6].

There are 4 common MRI patterns of spinal TB: paradiscal, anterior, central, and posterior [7]. Paradiscal, which is the most common, demonstrates disc space narrowing with low signal on T1 and high on T2 with possible epidural or paraspinal abscesses [7]. Anterior shows subligamentous abscesses, preservation of the discs, and abnormal signals involving multiple vertebral segments [7]. Central includes abnormal signalling of the vertebral body with preserved disc, indistinguishable from metastasis or lymphoma [7]. Posterior is rare and includes vertebral bone erosion and associated abscess [7].

Management of spinal TB is dependent on neurologic deficits. In the absence of, systemic medical management with RIPE therapy is often adequate [4]. When deficits are present, systemic treatment along with surgical intervention such as debridement, abscess drainage – such as in this case –, and even fusion or laminectomy may be necessary [4]. With early detection and treatment, the prognosis of spinal TB is favourable [8]. This emphasises how crucial it is to detect the disease as early as possible.

Written informed patient consent for publication has been obtained.