Pott’s disease: A case of multilevel vertebral tuberculosis with spinal deformity

Abstract

Spinal tuberculosis (TB), also known as Pott’s disease, occurs in 1%-5% of TB patients. Spine is the most common musculoskeletal extrapulmonary site of infection in TB, with the thoracolumbar region affected the most. Spinal involvement leads to significant deterioration of the vertebrae, paraspinal abscesses, spondylodiscitis and may involve the spinal cord leading to neurologic deficits. Nonspecific signs and symptoms of back pain often delay and complicate the diagnosis. Computed tomography (CT) and magnetic resonance imaging (MRI) are the commonly used modalities for diagnosis as each can identify early bone destruction and abscess formation. MRI is highly sensitive for detecting disc and cord involvement. We present a case of a 29-year-old male with long standing back pain, diagnosed to be Pott’s disease, discussing the role of imaging through computed tomography (CT) and MRI in diagnosis and management of the disease.

Introduction

Spinal tuberculosis (TB), or Pott’s disease, is a rare case of extrapulmonary TB bacterial infection that degrades the vertebral morphology. TB is a relatively common but serious infection, responsible for roughly 10 million infections and 2 million deaths globally per year [1,2]. Extrapulmonary cases specific to the spine are less common, accounting for approximately 1%-5% of TB patients, however, they are imminently dangerous as neurological function is susceptible and often affected leading to long-term morbidity [3]. Antitubercular treatment (ATT) including the RIPE regimen (Rifampin, Isoniazid, Pyrazinamide, and Ethambutol), remain the mainstay treatment for spinal TB, however, increasing concern for drug-resistant TB is threatening the effectiveness of current treatment options [4]. We report the case of a 29-year-old male with Pott’s disease of the lower thoracic spine. We focus on the use of conventional imaging modalities, such as computed tomography (CT) and magnetic resonance (MR) imaging, for coordination with clinical and pathological studies for accelerated and improved diagnoses.

Case presentation

A 29-year-old male with no significant past medical or surgical history presented to the emergency department after abnormal radiograph image findings at his local chiropractor’s office. His chief complaint upon admission was persistent back pain. It started in the lower back over the past year and progressed to mid-back in the past 3 months. The image findings were suspicious of TB infection, but the patient was unaware of any incident of exposure to TB. He is a construction worker from Mexico, but he did not report any recent travel history. His pain was moderate to extreme while testing spinal mobility and physical examination revealed no neurological abnormalities, however, he did have noticeable kyphosis in the mid-lower thoracic region. A CT without contrast was performed, and the findings were significant for paraspinal mass and suspicious for an abscess predominately around the T6-T12 region with associated erosive changes in the vertebrae (Figs. 1 A-G). The largest paraspinal mass was located at T12 measuring approximately 8.0 × 5.5 cm. Erosive changes were observed throughout T6-T12 with marked deformities of the T10 and T11 vertebral bodies. This was the level at which the kyphotic curvature was most severe. Those findings were highly suggestive of Pott’s disease. An MRI of the thoracic spine with and without contrast was performed for correlation (Figs. 2 A-D). Extensive vertebral, disc, paraspinal, and epidural abnormalities were noted in the mid/low thoracic and lumbar spine with accentuated mid/lower thoracic kyphosis. Again, discrete rim-enhancing fluid collections were noted in the ventral and dorsal paraspinal space with the largest collection on the right paraspinal station from T12-L4 measuring 17.8 cm. Enhancing epidural tissue and fluid collection from T7-T12 contributed to mild-moderate canal stenosis and mild ventral cord deformity. However, there was no cord signal abnormality. Those findings were most consistent with Pott’s disease.

Fig. 1.

A 29-year-old male with abnormal chest imaging at his chiropractor’s office and history of back pain. Chest CT scan without contrast demonstrated bilateral paraspinal masses (white arrows –A,B,C), predominantly in the T6-T12 vertebrae. Erosive changes are noted along the vertebrae in the lower thoracic region (T6-T12), with marked deformities of T10 and T11 with focal kyphosis (yellow arrow – D,E). Cinematic rendering in the sagittal (F) and coronal (G) views illustrated the eroded and compressed vertebrae in detail (white arrow F, G) and eroded ribs were also seen (yellow arrow – G). Findings were consistent with Pott’s disease with paraspinal involvement.

Fig. 2.

29-year-old male with no significant past medical or surgical history presented to the emergency department after abnormal spinal image findings on outside radiography. Sagittal short tau inversion recovery (STIR) (A) and post-contrast T1-weighted (B) image of the thoracic and lumbar spine showed T2 hyperintense signal with heterogeneous contrast enhancement of the vertebral bodies from T9-T12 (arrows). There was associated destruction of the vertebral bodies, endplates, accentuated kyphosis, with effacement of the ventral thecal sac. Axial T2-weighted (C) and post-contrast T1-weighted MR images of the thoracic spine demonstrated heterogeneous T2 hyperintense signal and enhancement of the thoracic spine vertebral associated with rim-enhancing T2 hyperintense ventral epidural fluid collection (arrows) with compression and effacement of the ventral thecal sac.

Following consultation with neurosurgery, it was recommended the patient remain in a thoracic lumbar sacral orthosis (TLSO) brace when upright. Further consultation with the surgical team regarding the correction of thoracic kyphosis and TB spondylitis was rendered non-emergent. In the meantime, the patient is receiving IV morphine and lorazepam as needed for intense back pain and anxiety. In addition, orders were placed for enoxaparin to prevent deep vein thrombosis.

After obtaining sputum and paraspinal specimens for acid-fast bacillus (AFB) testing, the patient was seen by infectious disease where he started on the ATT with the RIPE regimen for 6 months. Three pulmonary samples came back negative, and the paraspinal abscess sample came back positive for Mycobacterium tuberculosis, confirming Pott’s Disease. Due to inconsistent follow-ups and medication usage, the treatment regimen was prolonged for 12 months. After a 12-month follow-up with infectious disease, the patient’s medication was discontinued, and a follow-up was scheduled for 6 months.

Discussion

We present the rare case of Pott’s disease, an uncommon occurrence of extrapulmonary TB. Epidemiological information is limited, but from the available literature, extrapulmonary TB infection burdens children and women slightly more than men, and the median age of incidence is 24 years [5,6]. Less-developed countries and poverty-stricken populations are most affected by TB overall. While the lungs are overwhelmingly the most affected organ, other sites can be affected, including lymph nodes, gastrointestinal tract, genitourinary system, integumentary system, and bones [7]. Spinal TB is the most common site of musculoskeletal extrapulmonary cases, presenting in approximately 1%-5% of all cases of TB [2]. The thoracolumbar junction is the most commonly affected section of the spinal column, followed by the lumbar and the cervical spine [8]. Involvement of the spine is often difficult to manage and results in large deterioration of major structural components. Neurological impact also contributes to complications during diagnosing and subsequent recovery.

Clinically, Pott’s disease can be difficult to diagnose. Most often patients present with mild to moderate symptoms with the chief complaint of persistent back pain. Other constitutional symptoms may include weight loss, fever, or lack of appetite [9]. Nighttime discomfort is a telling sign, often waking the patient and preventing sleep. Radicular discomfort directed towards the stomach is common and mimics abdominal disorders like cholecystitis, pancreatitis, appendicitis, and renal disease, causing major delays in diagnoses [10]. In addition, compression, instability, and inflammatory changes in the spinal cord impose significant neurological deficits in up to 75% of spinal TB cases. Neurological deficit from TB is divided into 2 subtypes; paraplegia of early onset (with active disease) and paraplegia of late onset (with healed disease). With each, the spinal cord may develop edema, cord atrophy, or syrinx and interstitial gliosis which can be demonstrated on CT or MRI [11,12].

Spondylodiscitis is often seen in radiological studies of suspected Pott’s disease because of its involvement of the disk and vertebra, representing 47%-94% of spinal TB cases. Spondylodiscitis is seen in the lower thoracolumbar region in approximately 80% of cases and 4%-15% of cases in the cervical spine, while only 2%-3% of cases appear in the lumbosacral spine [13,14]. Conventional radiography (CXR) is unlikely to adequately show distinct characteristics of Pott’s disease unless the disease has progressed into later stages—usually described as >50% deterioration of vertebra. Otherwise, soft tissue extension is difficult to see unless paravertebral calcifications develop. [13] CT depicts early foci of bone infection and paraspinal involvement better than conventional radiography (CXR) and is useful in characterizing early bone destruction, cortical resorption, and other spinal deformities. Paravertebral spinal abscesses are well depicted, usually appearing as large, bilateral hypodense collections encased by thin vascularized walls, sometimes containing distinct calcifications [[13], [14], [15]]. Disc involvement is better assessed on MRI than CT, and its sensitivity makes it best for detection and following of spinal TB [16]. MRI can detect early inflammatory marrow and endplate changes before deformation or destruction. It is useful in evaluating cord compression and the presence of intramedullary lesions. While late chronic stage signals can vary, characteristic findings of spinal TB consist of hypo intensity on short tau inversion recovery (STIR) and T1 weighted images of vertebra and disc spaces, but with a marked T2-hypointensity in the vertebral body with T2-hyperintensity in the intervertebral disk [13,17,18]. In our case, MRI was optimal for visualizing ventral epidural fluid collection with compression and effacement of the ventral thecal sac. Early usage of contrast enhancement can also improve accuracy and detection as inflammatory marrow edema appears heterogeneous, and late-stage disc involvement loses much of its enhancement [17].

Treatment of spinal TB is slightly more involved as the integrity of the spinal column must be considered. Generally, stabilization of the spinal column can be sufficed by a specialized back brace, allowing for pharmaceutical intervention to occur without risk of sudden structural changes. Currently, the RIPE regimen (Rifampin, Isoniazid, Pyrazinamide, and Ethambutol) is standard for treating spinal TB and lasts between 6 and 9 months and involves one intensive phase and one continuation phase. [2,4] However, rising concern for multi-drug resistant (MDR) spinal TB presents a challenge in management. Acid fast bacilli (AFB) are demonstrable in approximately only 10%-30% of MDR cases, presenting a diagnostic challenge. [[19], [20], [21]] According to the Medical Research Council, cases that do not require mechanical adjustment or lack neurological deficiencies, surgical intervention is not indicated [22]. In cases where mechanical instability requires debridement and fusion or spinal compression is severe, surgical intervention is necessary [21]. Prognosis of spinal TB is generally very good when caught early enough, with 82%-95% of patients responding positively to ATT and most showing improvements in neurological deficits [21].

Conclusion

This case highlights the clinical complexity and diagnostic challenges of Pott’s disease, a rare form of extrapulmonary TB in the spine. The use of advanced imaging modalities such as CT and MRI were valuable in identifying characteristic features of spinal TB and guiding subsequent intervention. Although the patient faced initial delays in presentation and non-compliance to medication, comprehensive medical management with the RIPE regimen and non-surgical stabilization led to a favorable outcome. This case reinforces the importance of early recognition, multimodal imaging coordination, and consistent treatment adherence in achieving timely and accurate diagnoses and successful management in patients with spinal TB.

Patient consent

The patient reported in the manuscript signed the informed consent/authorization for participation in research, which includes the permission to use data collected in future research projects such as the presented case details and images used in this manuscript.