CLINICAL PROFILE AND ETIOLOGICAL EVALUATION OF NON-TRAUMATIC MYELOPATHIES USING MAGNETIC RESONANCE IMAGING

Objective: The present study was conducted with an objective to identify the etiology of non-traumatic myelopathies of both compressive and non- compressive types with the aid of magnetic resonance imaging (MRI). Methods: This retrospective observational cross-sectional study was conducted on 100 patients with a clinical diagnosis of non-traumatic myelopathy belonging to the age group of 15–75 years from August 2018 to July 2020 in the Departments of General Medicine and Radiodiagnosis of MKCG Medical College and Hospital, Berhampur, Odisha. Detailed history, clinical evaluation, laboratory investigations, and findings of MRI spine and brain were compiled. Results were analyzed using descriptive statistics. Results: Among 100 patients of non-traumatic myelopathy, 65 patients presented with compressive myelopathy and 35 patients with non-compressive myelopathy where 56 patients presented with paraparesis and 44 with quadriparesis. Pott’s spine (n=25, 38.46%) and acute transverse myelitis (ATM) (n=24, 68.57%) were the most common etiologies found in compressive and non-compressive groups, respectively. Conclusion: Pott’s Spine, spondylotic myelopathy, and ATM were the most common etiologies of non-traumatic myelopathy. MRI has proven to be the ultimate imaging modality for their etiological evaluation.


INTRODUCTION
Myelopathy describes any neurologic deficit related to the spinal cord [1]. It can be either traumatic or non-traumatic. Non-traumatic spinal cord diseases constitute one of the most common groups of neurological diseases in medical practice [2]. It is a broad and heterogeneous group of etiologies, summarily divided into compressive and non-compressive diseases [3], which include vertebral spondylosis, neoplasm, infections, vascular ischemia, multiple sclerosis (MS), motor neuron disease, radiation myelopathy, syringomyelia, paraneoplastic syndrome, and Vitamin B 12 deficiency.
Spinal cord diseases often have devastating consequences, ranging from quadriplegia and paraplegia to severe sensory deficits. Many of these diseases are potentially reversible if recognized and treated at an early stage. Thus, they are among the most critical neurologic emergencies, where prognosis depends on an early and accurate diagnosis [4].
Clinically, the diagnosis of myelopathy depends on the neurologic localization of the finding to the spinal cord, rather than the brain or peripheral nervous system and then to a particular segment of the spinal cord. The antecedent clinical syndrome and other details of the patient's course are helpful, but imaging plays a crucial role [1].
The incidence, demographics, clinical presentations, and outcomes for the non-traumatic spinal cord injury/disease (SCI/D) population have not been as thoroughly studied as in persons with traumatic SCI [5].
Magnetic resonance imaging (MRI) is the mainstay in evaluation of myelopathy. It has improved imaging of the spinal cord lesions to a point that reliable diagnosis of even a non-expansible lesion is routinely possible [6].
The present study was aimed at evaluating the clinical profile and etiology of non-traumatic myelopathies with the aid of MRI.

METHODS
This retrospective observational cross-sectional study was conducted on 100 patients of non-traumatic myelopathy admitted in the medical and neurology wards of MKCG Medical College and Hospital, Berhampur, Odisha, from August 2018 to July 2020. Information on routine and laboratory tests of patients such as complete blood count, serum urea, serum creatinine, fasting blood sugar, liver function tests, electrocardiography, Mantoux test, erythrocyte sedimentation rate, chest X-ray, plain X-ray of spine, and specific investigations such as collagen profile serum Vitamin B 12 , serum HIV, ultrasonography of abdomen and pelvis, cerebrospinal fluid analysis, and nerve conduction study were compiled. MRI spine and MRI brain study findings were collected from the department of radiodiagnosis.

Inclusion criteria
Patients of both sexes and greater than 15 years of age with symptomatic cases of non-traumatic paraparesis and quadriparesis were included in this study.

Exclusion criteria
Cases with contraindication for MRI (such as prosthetic heart valve, implanted pacemaker, or any other orthopedic metallic implant) were excluded from this study.

Statistical analysis
Results were analyzed using Microsoft Excel 2010 using descriptive statistical tools such as frequencies, mean, ± standard deviation (SD), and percentages.

RESULTS
Out of 100 patients of non-traumatic myelopathy, 57 were male and 43 were female with an age group of 15-75 years and a male-to-female ratio 1.33:1 (Table 1). In this study, maximum number of patients (30%) was in the age group of 46-55 years followed by 21% in the age group of 36-45 years.
The mean (±SD) age of the study population was 44.75 (±13.88) years.
Out of 100 cases, number of compressive myelopathy was 65 and noncompressive myelopathy was 35 ( Table 2).
Thirty-seven patients were presented with acute onset of illness, 21 with subacute onset while the remaining 42 patients had a chronic presentation of illness.
Various locations of the lesions found in our study involved lumbar, dorsolumbar, dorsal, cervicodorsal, and cervical where cervical lesions were found in maximum number of patients (39%).
The dorsal spine was most frequently affected by tuberculosis. The most common site of involvements for cervical spondylotic myelopathy were cervical C4/C5 and C5/C6, whereas for ATM, the common site of involvement was dorsal spinal segment.
Out of nine cases with tumors, three cases had intramedullary and six cases had extramedullary-intradural lesions.

DISCUSSION
Rapid diagnosis and early treatment of non-traumatic myelopathy are crucial determinants of long-term recovery and favorable prognosis of a patient. Therefore, the treating physician has to be well acquainted with various clinical presentations and diagnostic aids for nontraumatic myelopathy [7]. Very limited statistical data are available on this incidence. The present study was aimed at investigating the clinical and etiological profile of non-traumatic myelopathy.
In 2013, the World Health Organization reported that the incidence of non-traumatic myelopathies was higher in male than in females and incidence steadily increased with age [8]. The present study shows a similar result where male and female percentages were 57% and 43%, respectively (Table 1). Similar findings were observed in studies done by Haleem et al. [9] in Bangladesh, where 62% were male and 38% were female and the highest number of patients was in the age group of 51-60 years which correlates to the present study of maximum number of patients in the age group of 56-65 years ( Table 1).
The present study observed that 65% of cases had compressive myelopathy and 35% had non-compressive myelopathy which is similar to the study of Chaurasia et al. [10], where out of 204 patients, former cases were found to be 62% and the later to be 38% (Table 2).
Pott's spine (n=25, 38.46%) was the most common cause of compressive myelopathy in the present study followed by spondylotic myelopathy (n=23, 35.38%) ( Table 3) which correlates well with various Indian studies [10][11][12]. All the patients of Pott's spine in our study were having paraparesis where it was found to be 93.3% in the study of Chaurasia et al. and 91.7% in the study of Haleem et al. A similar observation has been found by Deivigan et al. [13]. In our study, bladder-bowel was found to be involved in 52% of cases whereas 80% of cases had sensory symptoms. Similar findings have been observed in cases of Haleem et al.
MRI suggested most common sites of involvement were at T(7-10). Pott's spine featured signal intensities appearing hypointense on T1W and hyperintense on T2W sequences with heterogeneous enhancement of the vertebral body. MRI plays an important role in the diagnosis of spinal TB with a high specificity and sensitivity [14].
Spondylotic myelopathy was the second most common cause of compressive myelopathy in the present study group, incidence being 35.38%. Out of 23 patients, 20 (86.95%) patients were presented with quadriparesis and three patients with paraparesis. Most of the patients presented with disc degeneration, stenosis, osteophyte formation at the level of facet joints, and segmental ossification of the posterior longitudinal ligament. Twelve (52.17%) patients had multiple levels of involvement (C3-C8). Most frequent levels of involvement were seen at C4-C5 and C5-C6. One hundred and seventy-three patients of Nagata et al. [15] study with cervical myelopathy observed the most frequent levels of involvement at C3-C4, C4-C5, and C5-C6. MRI findings such as disc protrusion, abutting and flattening the ventral cord surface, and intramedullary high signal intensity on T2WI in the spinal gray matter causing cord deformity with associated cord edema confirmed the diagnosis in our study.
The third most common cause of non-traumatic compressive myelopathy was tumor (n=9, 13.85%). Studies from Chaurasia et al.  show the occurrence to vary from 20% to 30%. Most of the tumors in the present study were intradural extramedullary comprising meningioma (n=4) and neurofibroma (n=2) and rest were intramedullary comprising ependymoma (n=2) and secondaries (n=1) which show similarity with the study of Kumar et al. [16]. MS was the third most common cause in non-compressive myelopathy group. Three patients had paraparesis and one had quadriparesis. MRI findings of brain showed multiple high signal lesions seen, particularly in the periventricular region on T2 image.
The other etiologies of our study were found to be syringomyelia, multiple myeloma, ADEM, and HIV myelopathy with a very few numbers of cases.
The major limitations of our study population are its smaller sample size and hence the results cannot be generalized to the whole population of non-traumatic myelopathy.
MRI depicts the spinal cord directly, assesses its contour and internal signal intensity characteristics reliably and non-invasively so we can evaluate associated cord edema or contusion and also the integrity and early changes in intervertebral discs and ligaments which can be crucial in long-term prognosis of the patients [16].

CONCLUSION
Pott's spine and spondylotic myelopathy were the most common etiologies of non-traumatic compressive myelopathy and ATM was the most important etiology in the non-compressive group. MRI has proven to be the ultimate imaging modality for their etiological evaluation.