New diagnostic criteria combining clinical history, cerebrospinal fluid (CSF) analysis, and neuroimaging have been proposed to improve the diagnosis of spontaneous spinal cord infarction (SCI).
Investigators compared the medical records of patients diagnosed with spontaneous SCI to those of patients with alternative myelopathy etiologies. Based on this comparison, they propose spontaneous SCI be diagnosed in the setting of:
Clinical signs and symptoms: Acute, nontraumatic myelopathy symptoms which develop within 12 hours or sooner;
MRI findings including no spinal cord compression; intramedullary T2-hyperintense spinal cord lesion (supportive finding); and one of the following: diffusion coefficient restriction, associated vertebral body infarction, or arterial dissection/occlusion adjacent to the lesion;
No likely alternative diagnoses.
"Misdiagnosis of spontaneous SCI happens very frequently, especially in the absence of an inciting event such as aortic surgery, with transverse myelitis being a common misdiagnosis," Nicholas Zalewski, MD, senior associate consultant, division of MS and autoimmune neurology, Mayo Clinic, Rochester, Minnesota, told Medscape Medical News.
"These diagnostic criteria are meant to improve accurate diagnosis so that the patient can receive appropriate therapy and avoid unnecessary and harmful aggressive immunotherapies typically given when the patient has been misdiagnosed," he said.
The study was published online September 24 in JAMA Neurology.
No Current Diagnostic Criteria
Spontaneous SCI is nonprocedural and nontraumatic, and diagnosis is "challenging without an inciting event such as a surgical procedure," the authors write.
When patients are incorrectly diagnosed and treated for other conditions — typically transverse myelitis — they are exposed to "unnecessary and possibly deleterious treatments, as well as missed treatment opportunities and secondary stroke prevention," the authors state.
"The first suspicion when a patient presents with myelopathy is usually that it is inflammatory, but we saw case after case in which SCI was ultimately diagnosed," Zalewski said.
"There are key characteristics in the history, exam, and neuroimaging that stuck out as very typical of SCI and very atypical for inflammatory myelopathy, but there were no diagnostic criteria to help parse this out," he continued.
"I thought it was important to put forward good working criteria to distinguish spontaneous SCI from other myelopathies," he said.
The researchers reviewed Mayo Clinic electronic medical records from January 1, 1997 to December 1, 2017 to identify adult cases of spontaneous SCI (n = 133, median age [interquartile range], 60 [52 – 59]).
They used insights from confirmed cases of periprocedural SCI (n = 75) to better characterize the clinical, laboratory, and radiologic features of spontaneous SCI, which informed the proposed diagnostic criteria.
They also compared patients with spontaneous SCI to 280 patients with alternative intrinsic myelopathy etiologies to see if these patients met the proposed SCI diagnostic criteria at the time of clinical presentation.
The researchers analyzed the patients' clinical presentation, laboratory evaluations, CSF evaluation, and neuroimaging data.
Nadir Within 12 Hours
Of the 133 patients age 18 years or older with a spontaneous SCI, 53% were women, 93% were white, and median age at presentation was 60 years (52-69 years).
Spontaneous SCI presented with rapid severe deficits, with 77% of patients showing a nadir within 12 hours.
"Nadir" consisted of severe acute deficit (motor and/or sensory), typically consisting of loss of antigravity strength or worse, and severe objective sensory loss impairing function (eg, severe sensory ataxia).
Of these, 23% of patients had a more prolonged time to nadir; however, all but one showed rapid decline and severe deficits within 12 hours.
Selective pain and temperature sensory loss were present in 39% of 126 patients and severe back/limb pain was reported at onset in 72% of 96 patients.
In a quarter of patients, a specific physical maneuver took place at or proceeding onset.
Of the 133 patients with spontaneous SCI, 101 (76%) had vascular risk factors, with hypertension as the most common (46%), followed by smoking (46%), hyperlipidemia (43%), and diabetes (16%).
The most common co-occurring vascular disorder was coronary artery disease (11%), followed by peripheral vascular disease (8%), atrial fibrillation (6%), and previous cerebral ischemia (2%).
No patient had CSF findings consistent with a specific infection, autoantibody-mediated myelopathy, or other etiology.
Despite severe deficits, 30 patients (24%) initially had a normal MRI result.
Subsequent imaging, however, was abnormal: characteristic MRI T2-hyperintense patterns included owl eyes (82 [65%]) and pencil-like hyperintensity (50 [40%]). Moreover, gadolinium enhancement (37 of 96 patients [39%]) was often linear and located in the anterior gray matter.
Diffusion-weighted imaging/apparent diffusion coefficient restriction (19 of 29 [67%]), adjacent dissection/occlusion (16 of 82 [20%]), and vertebral body infarction (11 [9%]) were found on MRI and considered confirmatory.
The lesion axial localization and imaging pattern varied over the length of the lesion, with a single infarct potentially having multiple patterns.
The posterior one third of the spinal cord was involved on one or more imaging slices in 57 patients (45%).
Vascular imaging, including CT angiography, magnetic resonance angiography, or digital subtraction angiography, was performed in 82 patients, of whom 20% were found to have a specific abnormality.
No specific contributing arrhythmia was identified on ambulatory 24-hour Holter monitor in the 18 patients who received this evaluation, but some abnormalities were found on echocardiogram.
Abnormal laboratory findings included HbA1c (> 5.6%; 48%) and elevated low-density lipoprotein cholesterol (> 100 mg/dL; 53%).
Mild inflammation in was found in the CSF of seven of 89 patients (8%). Of note, aquaporin-4-IgG was negative in the 54 patients evaluated.
Over half of patients (56%) were treated with immunotherapy for suspected immune-mediated condition, with corticosteroids being most common, followed by intravenous immunoglobulin and plasma exchange.
Blood pressure augmentation was used in nine patients, followed by lumbar drain, and intravenous tissue plasminogen activator (tPA) (eight and two patients, respectively).
Anticoagulation and antiplatelet therapies were initiated in 11 and 92 patients respectively.
No patients developed recurrent episodes of SCI during follow-up.
Proposed Diagnostic Criteria
Based on the findings of the analysis, researchers suggested diagnostic criteria for SCI using the terms "definite," "probable," and "possible" SCI.
1. Clinical signs and symptoms: Acute, nontraumatic myelopathy (no preceding progressive myelopathy): onset to nadir deficits ≤ 12 hours, even if stuttering deficits develop in > 12 hours.
2. MRI findings: (a) No spinal cord compression. (b) Intramedullary T2-hyperintense spinal cord lesion (supportive finding). (c) Specific: one of the following: diffusion-weighted imaging/apparent diffusion coefficient restriction; associated vertebral body infarction; arterial dissection/occlusion adjacent to the lesion.
3. CSF noninflammatory (normal cell count, IgG index, and no oligoclonal bands).
4. No likely alternative diagnoses.
Types of SCI:
Definite spontaneous (1, 2a, 2b, 2c, 4).
Probable spontaneous (1, 2a, 2b, 3, 4).
Possible spontaneous (1, 4).
Definite periprocedural (1, 2a, 2b, 4).
Probably periprocedural (1, 4).
Of the patients in the study, 29.3% were definite, 62.4% were probable, and 7.5% were possible. Only one patient did not meet the diagnostic criteria.
Of the 280 patients from the validation cohort, 9 (3.2%) met criteria for possible SCI at presentation; however, diagnostic evaluation suggested an alternative diagnosis in all patients.
No patients met the criteria for definite or probable SCI.
"The main thing to focus on is that each part of the criteria is very important, but most important is the initial criteria, which is mandatory, acute severe myopathy with nadir deficits within 12 hours or less — such a typical scenario for SCI should immediately raise suspicion," Zalewski emphasized.
"Imaging findings should be consistent with the T-2 pattern, but that can look like a lot of other things, suggesting possible or probable [SCI] versus definite," he continued.
Recognition Precedes Treatment
Commenting on the findings for Medscape Medical News, Orhun Kantarci, MD, consultant in neurology and associate professor of neurology, Mayo Clinic, who was not involved with the study, said that "until this study, we did not have a good handle on how to define the imaging and say, 'This looks like a spinal cord infarction.' "
He noted that the study was "done specifically in the setting of people who'd had procedures, but once the pattern was identified — which was the key issue — it was possible to recognize [the pattern] even in patients without the classic prodrome of a surgical procedure."
Knowing this helps distinguish spontaneous SCI from other diagnoses, notably transverse myelitis, which can "fool people on initial assessment, especially since it seems to respond to steroids at first because steroids help with edema and perhaps some spinal cord recovery, but not with the actual infarction."
"The biggest contribution of this study is that we can now understand the problem, and the future will show whether this contribution will be relevant in terms of actually impacting patients," he said.
Zalewski commented, "The main thing is perfusing the spinal cord and avoiding things that might harm the patient medically or neurologically."
He added, "It remains to be seen what can be done further for patients presenting with spinal ischemia and whether tPA can be used — but first and foremost, if we are not recognizing these cases acutely, we don't know who will respond to which treatment and whether we can design any trials."
Zalewski and Kantarci have reported no relevant financial relationships. Disclosures for the other authors are listed in the article.
JAMA Neurol. Published online September 24, 2018. Abstract
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Cite this: New Diagnostic Criteria for Spontaneous Spinal Cord Infarction - Medscape - Oct 04, 2018.