Myelitis: A Common Complication of Tuberculous Meningitis Predicting Poor Outcome

Abstract

Background: Myelitis is an important complication in patients with tuberculous meningitis (TBM). However, a paucity of publications exists on the spectrum of neurological and MRI findings of TBM-related myelitis. The risk factors and prognosis of myelitis in patients with TBM are not fully understood. Therefore, this study aims to identify the risk factors, clinicoradiological features, and prognostic impact of myelitis for patients with TBM.

Methods: We conducted a retrospective study in our institution. Patients with TBM who were consecutively admitted during the period of August 2015 to December 2019 were included. We reviewed the demographic characteristics, clinical, laboratory and MRI findings, and clinical outcomes of all of the included patients. The diagnosis of myelitis was identified by a hyperintensity on T2-weighted images that were associated with cord edema, enlargement, and marginal or no enhancement on contrast-enhanced images.

Results: A total of 114 patients were included. Myelitis occurred in 19 (16.7%) patients, five of whom paradoxically developed myelitis. The common clinical signs of myelitis were paraparesis (738.9%), quadriparesis (844.4%), urinary retention or constipation (1,477.8%), and paresthesias in the lower limbs (1,052.6%). In the MRI findings, the hyperintensities on T2-weighted images involved more than 3 spinal cord segments. Myelitis was often combined with other forms of spinal cord injury, including 10 patients (52.6%) with spinal meningeal enhancement, 7 patients (36.8%) with enlargement of the central canal of the spinal cord, 6 patients (31.6%) with tuberculoma, and 4 patients (21.1%) with arachnoiditis and 1 patient (5.3%) with cerebrospinal fluid (CSF) loculations. None of the 5 patients with paradoxical myelitis were complicated with spinal meningeal enhancement and arachnoiditis, while 4 patients were complicated with enlargements of the central canal of the spinal cord. In multivariable analysis, a grade III disease severity on admission [p = 0.003, odds ratio (OR) = 8.131, 95% CI: 2.080-31.779] and high CSF protein (p = 0.033, OR = 1.698, 95% CI: 1.043-2.763) were independent risk factors for myelitis. After the 6 months follow-up, myelitis (p = 0.030, OR = 13.297, 95% CI: 1.283-137.812) and disturbance of consciousness (p = 0.042, OR = 12.625, 95% CI: 1.092-145.903) were independent risk factors for poor outcomes.

Conclusion: Myelitis was a common complication of TBM and independently predicted a poor outcome. A grade III disease severity and high CSF protein on admission were independent risk factors for myelitis. Paradoxical myelitis was rarely complicated with spinal meningeal enhancements and arachnoiditis, indicating that the immune reaction may play a dominant role.

Keywords: immune reaction; myelitis; paradoxical reaction; prognosis; tuberculous meningitis.

Figure 1

Flow chart of the study. The common signs suggesting spinal cord or spinal nerve root involvement include weakness, pain and paresthesia in the lower limbs or all the four limbs, urinary retention, and constipation.

Figure 2

Myelitis in a 53-year-old woman with tuberculous meningitis. The patient suffered from paraparesis with the duration of 8 weeks. MRI showed longitudinally myelitis. T2-weighted imaging showed a stripped-like hyperintensity (A). In the T1 contrast-enhanced sequence, uneven enhancements of the lesions were noticed (B). T2-weighted sagittal and axial images showed an uneven enlargement of the spinal cord and syringomyelia. The syringomyelia manifested as a stripe of intramedullary near-water signals (long arrow) and enlargement of the central canal (short arrow) (C,D).

Figure 3

A 31-year-old male patient developed paradoxical myelitis. The patient developed new spinal cord lesions 3 months after the start of antituberculosis treatment, when his symptoms of headache, fever, and disturbance of consciousness were gradually alleviated. A T1-weighted sagittal image of the thoracic spinal cord of the patient showed a spot-like hypointensity (A). In the T2-weighted sequence, multiple patchy hyperintensities in the spinal cord can be seen (B). T2-weighted sagittal and axial images of the cervical spinal cord showed an enlargement of the central canal in the spinal cord (C,D).

Figure 4

The evolution of myelitis in the same patient is shown in Figure 3. The patient's first spinal MR examination showed no abnormalities (A). 3 months later, there were multiple flaky hyperintensities in the cervical and thoracic spinal cord in the sagittal view of the T2-weighted sequence (B). 4 months later, the original lesion was absorbed (C).