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Título

The Importance of Dynamic Magnetic Resonance Imaging in the Diagnosis of Cervical Myelopathies: A Case Report

RESUMO

Case report: A 62 year old man was admitted to our service due to weakness in lower limbs and unsteadiness. Symptoms began 3 months before, with pain and numbness in his hands, evolving to bilateral and symmetrical weakness in lower limbs. The weakness became worse 4 days before admission, after receiving the 2nd dose of Covid-19 vaccine. There was no history of trauma, constitutional nor sphincters complaints. On neurologic examination, he showed a global MRC strength grade 5, except for 4+ on hip flexion and 4+ on hip abduction. There were signs of bilateral pyramidal release in lower limbs. He had a reduced proprioception and doubtful touch and pain hypoesthesia at T12 and T4 level, respectively, and he was unable to stand without assistance. He had sensory ataxia in all limbs, worse in his legs. Results of laboratory exams and CSF were unremarkable. The cervical spine MRI showed an nonspecific T2 signal heterogeneity at C4-C5. Based on the findings, the hypothesis of a post vaccinal inflammatory myelopathy was made and the patient went under pulse therapy with 1g methylprednisolone for 5 days, without objective improvement. Because of the atypical presentation of an inflammatory mielitis and for the differential diagnosis of compressive spondylotic myelopathy (CSM), a dynamic cervical spine MRI was requested. The exam revealed a canal stenosis at C4-C5. The patient underwent laminectomy, spinal cord decompression and posterolateral cervical arthrodesis from C3 to C6. The procedure was uneventful and he evolved with progressive improvement of symptoms. Discussion: Cervical spondylotic myelopathy is the most common spinal cord disorder in the elderly. Diagnosis is based on clinical signs and symptoms associated with a radiological exam. The spinal cord is made under dynamic changes during flexion and extension. These changes lead to biomechanical stress with movement, which may aggravate damage in patients with critical cervical stenosis. Normal MRI is unable to detect those changes. Therefore, the dynamic MRI has a higher sensibility for the detection of CSM. Final comments: This case shows a patient with a typical presentation of subacute cervical of CSM, but no significant changes in MRI. The diagnosis was only confirmed after a dynamic cervical spine MRI. Hence, dynamic MRI is an additional image resource able to provide useful information when there is a high clinical suspicion for CSM and the standard radiological exam is inconclusive.

Palavras Chave

Myelitis, MRI, dynamic, inflammatory, myelopathy, spondylotic