Research Update: Clinical Approach to Myelopathy Diagnosis

By Amanda Fortune 

 

In a recent review article by Dr. Carlos Pardo, MD, he describes the clinical approach to myelopathies (diseases of the spinal cord) in terms of evaluation strategies, diagnostic approaches, and etiologic framework (cause of disease). Over the past two decades, technological advancements and increasing scientific knowledge have refined our characterization of different spinal cord diseases. As a result, we can expand the diagnostic spectrum of myelopathies which leads to better evaluation of patients with spinal cord disorders and ultimately better diagnosis and treatment. In this blog post, I will summarize the integrative strategy that Dr. Pardo proposes to evaluate patients with suspected myelopathies, his advice on diagnostic approach, and a framework for etiological diagnosis. 

The first point that Dr. Pardo addresses in his review is the concepts of myelopathy and myelitis. Myelopathy refers to any process that leads to spinal cord dysfunction and is commonly associated with motor, gait, and sensory issues. He notes that myelopathies can be further divided into two major groups based on their causes. The first group is inflammatory myelopathies, also known as myelitis, which refers to diseases of the spinal cord in which inflammation is the main cause. The other group refers to pathological processes, which are not related to inflammation. He then highlights the outdated nature of the term “transverse myelitis”, which broadly refers to all inflammatory spinal cord disorders. Due to the discovery of immunologic mechanisms related to autoimmune myelitis (MOGAD, NMOSD), better criteria for diagnosis of demyelinating disorders, and high imaging MRI techniques, we can now determine a more accurate diagnosis based on the specific cause of the inflammatory disease. Additionally, people with non-inflammatory myelopathies have often been misdiagnosed with transverse myelitis leading to the mismanagement of their symptoms with immune-based therapies that may be ineffective or even cause harm. 

Next, Dr. Pardo proposes the best clinical approach to patients with myelopathy. Recognizing symptoms associated with spinal cord disorders is extremely important for the clinician. This should entail the clinician taking a comprehensive clinical history that allows recognition of symptoms commonly associated with spinal cord dysfunction, the clinical course of symptom evolution (acute, chronic, etc.), the severity of neurological dysfunction, and potential triggering factors that preceded the onset of disease. Based on the history, the clinician should verify their findings and possible diagnoses with a detailed physical and neurological examination. 

Following the comprehensive history and neurological examination, the clinician should further investigate and verify the suspected diagnoses through laboratory testing, including blood tests and cerebrospinal fluid (CSF) analysis. Recent advancements in laboratory analysis have expanded our ability to differentiate clinically similar diseases by their root cause. For example, analysis of the patient’s blood can be used to identify biomarkers such as the MOG antibody or aquaporin-4 and therefore define a subset of patients with autoimmune inflammatory myelopathies. Analysis of CSF also reveals valuable information regarding the cause of myelopathies in terms of inflammatory versus non-inflammatory because the absence of inflammatory changes in the CSF may direct the clinician to look towards non-inflammatory causes of the disorder. 

The next approach that Dr. Pardo goes over is diagnostic neuroimaging, which is primarily focused on MRI of the spine but can also include spine CT, CT myelography, and angiography. High-imaging MRI techniques provide vital information regarding the number and distribution of spinal cord lesions, which are then used to identify different myelopathies and can distinguish between patterns related to inflammatory versus noninflammatory myelopathies. Brain MRI is also helpful to support these diagnoses. CT imaging may be used in times when MRI is contraindicated (patient has metallic implants or devices) and spine angiography is used to visualize the veins and arteries surrounding the spinal cord for vascular disease, but overall, MRI is the best diagnostic imaging tool for myelopathies. 

Rather than using the results from just the MRI or the CSF analysis, the information gathered from the clinical history, neurological examination, laboratory testing, and diagnostic neuroimaging should then be integrated by the clinician to determine a more precise diagnosis. The first step to determining a precise diagnosis is the categorization of inflammatory vs noninflammatory myelopathies. By grouping inflammatory myelopathies, the clinician can bring together myelopathies with a common disease process of neuroinflammation for a more targeted diagnosis and treatment. This integrative approach serves to replace the diagnosis of “transverse myelitis” with better descriptions of underlying causes of myelitis and myelopathy. Implementation of these guidelines should ultimately improve the accuracy of diagnosis and treatment methods for myelopathies and lead to better patient outcomes.