Can a diagnosis of multiple sclerosis be made without ruling out neuromyelitis optica spectrum disorder ?

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dCan a diagnosis of multiple sclerosis be made without ruling out neuromyelitis optica spectrum disorder ? Jagannadha Avasarala , Creed Pettigrew , Paige Sutton , Zain Guduru , Julie Gurwell , Brent S Sokola , Selina Mullins PII: DOI: Reference:

S2211-0348(20)30025-0 https://doi.org/10.1016/j.msard.2020.101949 MSARD 101949

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Multiple Sclerosis and Related Disorders

Received date: Revised date: Accepted date:

6 November 2019 8 December 2019 12 January 2020

Please cite this article as: Jagannadha Avasarala , Creed Pettigrew , Paige Sutton , Zain Guduru , Julie Gurwell , Brent S Sokola , Selina Mullins , dCan a diagnosis of multiple sclerosis be made without ruling out neuromyelitis optica spectrum disorder ?, Multiple Sclerosis and Related Disorders (2020), doi: https://doi.org/10.1016/j.msard.2020.101949

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Highlights  No prior study has proposed that NMOSD testing be mandated prior to a diagnosis of MS.  NMOSD testing may have to repeated depending on patient’s responsiveness to disease modifying therapies.  NMOSD testing may be required even if the phenotype is MS.

Can a diagnosis of multiple sclerosis be made without ruling out neuromyelitis optica spectrum disorder ? Jagannadha Avasarala MD, PhD1* , Creed Pettigrew, MD 1 , Paige Sutton, MD1 , Zain Guduru MD1 , Julie Gurwell PhD 1 , Brent S Sokola Pharm D, MS2 and Selina Mullins Pharm D, MBA2 1

Department of Neurology, University of Kentucky Medical Center, Kentucky Neuroscience Center, 740 S Limestone Dr., Lexington, KY 40536, USA and 2Specialty Pharmacy and Infusion Services, University of Kentucky, Lexington, KY 40536, USA *Address for correspondence Jagannadha Avasarala, MD, PhD Department of Neurology Section of MS and Neuroimmunology University of Kentucky Medical Center & Kentucky Neuroscience Institute 740 S Limestone Lexington, KY 40536 USA Abstract The symptoms of multiple sclerosis (MS) can overlap with neuromyelitis optica spectrum disorder (NMOSD). Although testing is available for aquaporin 4 (AQP4) and myelin oligodendrocyte glycoprotein (MOG) antibodies, screening for NMOSD is recommended but not mandatory to establish a diagnosis of MS. Methods and Results We queried 319, 994 individuals who filed claims for MS and NMOSD in a Truven Health Analytics (THA) database and had at least one year of uninterrupted health insurance coverage. Of this cohort, 2001 (0.62%) were diagnosed as having NMOSD after an initial diagnosis of MS, based on ICD 9/10 codes. Since THA only offers claims-based data, we initiated an individual patient-based data search at our medical center to screen for potential misdiagnoses. We identified 4/54 (7.4%) NMOSD cases that were initially diagnosed as having MS. Conclusions: The results from our small study have significant implications – symptoms, clinical presentation or classic radiological findings perhaps cannot reliably separate MS from NMOSD. If our study findings can be replicated, guidelines to diagnose MS ought to recommend that NMOSD be excluded first despite typical clinical and radiological findings pointing to MS.

Introduction Misdiagnosis remains a persistent concern in multiple sclerosis (MS) (Solomon et al., 2012; Solomon and Weinshenker, 2013). Some misdiagnoses of MS include migraine, fibromyalgia, non-localizing neurologic symptoms with abnormal MRI, conversion disorders, and neuromyelitis spectrum disorders (Solomon et al., 2016). The Institute of Medicine in 2015 described the need to approach misdiagnosis as a ‘moral, professional and public health imperative (Singh and Graber, 2015). Moreover, misdiagnosis is the third leading cause of death in the U.S. (Makary and Daniel, 2016). Data concerning misdiagnosis of MS may not be revealed by analysis of large datasets unless a systematic approach is developed to retrospectively screen MS patients included in large datasets for NMOSD. In the absence of such an undertaking, reliance is placed on illustrative case reports but that potentially limits a broader application of such isolated findings. Hence, a prospective approach to test for NMOSD in all cases diagnosed with MS, optic neuritis (ON), TM or central demyelinating syndromes is probably the best option to uncover the true incidence of NMOSD. Diagnosing MS relies on obtaining a careful history, performing a thorough neurological examination and applying McDonald criteria. These criteria were first developed first in 2001 and later modified in 2005, 2010 and 2017, respectively (McDonald et al., 2001; Polman et al., 2011; Polman et al., 2005; Thompson et al., 2018). Application of McDonald criteria to appropriate symptoms suggestive of a demyelinating disease unilateral ON, TM or cerebellar syndromes presenting with ataxia or nystagmus is key, along with exclusion of

mimics of MS. Even with such strict guidelines and the application of cerebrospinal fluid (CSF) analyses to support a diagnosis of MS, no single test can establish a diagnosis of MS or rule out NMOSD unless serology testing is performed (Thompson et al., 2018). A positive AQP4 or MOG Ab test cannot be dismissed as falsepositive given that the clinical phenotype is ever expanding in NMOSD. A case in point is an analysis of unilateral optic neuritis or a short-segment transverse myelitis – unilateral acute ON could represent NMOSD since ½ of patients with NMOSD present with isolated ON (Levin et al., 2013). Short-segment TM could also be part of NMOSD and could be missed unless carefully screened for (Carnero Contentti et al., 2018). It is worth noting that the diagnostic criteria for NMOSD with aquaporin 4 (AQP4) antibody positive status requires just one core clinical characteristic of ON, acute myelitis or area postrema syndrome (APS), among others (Wingerchuk et al., 2015). A diagnosis of NMOSD can also be made when AQP4-IgG Ab status is unknown or when testing is not available based on select MRI criteria when acute ON, acute myelitis, area postrema syndrome or acute brainstem syndrome presentation(s) are the presenting symptoms (Wingerchuk, 2015). This classification, however, does not apply to MOG Ab status patients. Currently, however, routine ordering for AQP4 Ab testing is probably not done for every isolated case of ON but typically limited to recurrent ON or bilateral ON. For acute TM that is limited to < 3 segments, testing for NMOSD is probably not generally ordered although individual practices could vary on whether testing is done. Since Wingerchuk criteria (2015) predated MOG-Ab testing that became available in 2017 in the U.S., no recommendations based on serum testing for MOG-Abs were possible in 2015. And although the revised McDonald criteria of 2017 for a diagnosis of MS indicate that testing for NMOSD be considered, it is not required or mandatory (Thompson et al., 2018). In this study, we analyze retrospective data to explore the if MS can be misdiagnosed in settings that overlap with NMOSD. In addition to overlapping clinical disease phenotypes, we speculate that NMOSD testing for both AQP4 and MOG Abs may be required when multiple (>2) drug failures in MS occur although more data are required to establish guidelines for treatment failure and when to test for NMOSD.

Methods This is a two-part study, consisting of an initial claims THA database extraction followed by analysis of IRBapproved cases from our medical center. Data included in the present study consisted of MS patients (ICD 9 and 10 codes, G 340 and G 35.0, respectively and all sub-codes) and ranged from January 1, 2009, to March 31, 2016. The dataset was restricted because of the purchase agreement between the University of Kentucky and Truven Health Analytics. The database contained 319,994 patients who were diagnosed with MS, based on ICD 9/10 codes. Once this dataset was established it was queried for NMOSD (G36.0) and we extracted 2001 patients that had the additional diagnosis of NMOSD. Since claims data cannot be used to extract individual patient data, we queried Mayo Laboratories for serum samples sent to them from our medical center for testing for AQP4 or MOG Ab. We identified 4/54 NMOSD cases that had findings suggestive of MS with typical characteristics of MS and highlight the fact that MS cannot be separated from NMOSD based on the clinical phenotype alone. The THA database contains inpatient and outpatient data sets; including outpatient prescription drug experience of employees and their dependents from all US census regions who are covered under a variety of fee-for-service and capitated health plans, as well as exclusive provider organization, preferred provider organization, and point of service plans as well as indemnity plans and health maintenance organization plans. The data are fully de-identified prior to analysis in compliance with Health Insurance Portability and Accountability Act regulations; thus, neither institutional review board approval nor informed patient consent was sought or required.

Individual cases mimicking MS Case 1: A 45-year old African American female with a history of depression and fibromyalgia was diagnosed with MS in 2004. The patient experienced multiple treatment failures owing to disease progression (Glatiramer acetate, Dimethyl fumarate, Interferon beta-1b, Interferon beta-1a SQ, and Mitoxantrone) until 2016. The first available MR of brain in our system was in 2013 and showed T2 hyperintense lesions in the corpus callosum, subcortical, deep and periventricular white matter; no T1-gadolinium enhancement was noted. MR of cervical spine was unremarkable but repeat imaging in 2016 showed a central T2 hyperintense lesion at T5-T6. Prior history included bilateral optic neuritis (ON) and lower extremity weakness. She was admitted in 2019 for 1 week of progressive diplopia, blurry vision, weakness, falls and dysarthria. An MRI of brain showed stable scattered T2/FLAIR hyperintensities in the subcortical, deep and periventricular white matter compatible with demyelinating lesions but no active lesions. MR orbits showed right optic nerve atrophy. C-spine was unremarkable. Testing for NMO/AQP4 was negative but MOG Ab was positive (1:20 titer); testing for NMOSD were ordered given her history of bilateral ON. She was started on Rituxan and is stable. Figure 2 (1A to 1C) shows representative lesions on FLAIR MRI of brain. Case 2: A 55-year-old male with history of hypertension and hyperlipidemia had an episode of (L) ON at age 33. Ten years later, he had recurrence of his (L) optic neuritis. He underwent an MRI of brain and had lesions consistent with MS but was not started on disease modifying therapy. At 53, he had (R) vision loss. When he first presented to us and underwent an MRI brain of brain, it was approximately about 2 decades after his initial symptom onset. The MRI of brain that we did revealed T2/FLAIR lesions involving the corpus callosum, peripheral white matter, basal ganglia, brainstem and middle cerebellar peduncles. His (L) optic nerve was atrophic. Two of the cerebral lesions were enhancing including the right optic nerve from the chiasm, distally, to the retrobulbar region. C-spine imaging was negative. Owing to history of bilateral optic nerve involvement, workup for NMOSD was initiated. Twenty years after his diagnosis of MS, serum AQP4 Ab testing was positive at 22.2 U/ml. This patient was started on Rituximab a few months after his AQP4 was positive, but he became legally blind. Repeat MR imaging two years later showed no new brain lesions. Figure 2 (2A, 2B) depict typical changes MRI of brain changes that show a pattern consistent with MS. Case 3 : A 34-year-old African American female with history of depression, obesity, fatigue at age 32 who developed intermittent left leg numbness one year later had an initial MRI of brain that showed multiple periventricular T2 hyperintensities with a distribution typical of MS (Figs 3A and 3B). Spinal cord imaging was obtained and showed lateral hyperintensities at C2 and C5-C6, an active lesion at C3, and patchy central hyperintensity in the thoracic cord. Three months after her diagnosis of MS, serum testing for NMOSD done to rule out mimics revealed MOG Ab titers positive at 1:40. The patient was diagnosed with NMOSD and started on Rituximab and with active follow-up. Case 4 : A 38-year-old female was diagnosed with MS at 24. Initial symptoms included dizziness. MRI of brain at an outside facility four years after her MS diagnosis showed T2 and FLAIR hyperintensities in the periventricular and pericallosal deep white matter (Fig 3, 4A to 4C). Therapy was initiated with Copaxone but discontinued due to continued breakthrough disease. She failed multiple disease-modifying drugs for the next few years with recurrent symptoms requiring IV steroids. Three years after diagnosis of MS, serum for NMOSD was ordered due to failure of therapy at an outside hospital. It was retested at our facility in October 2017 and was positive for AQP4 Ab at 4.5 units/ml. The initial MRI brain at our facility done in November 2018 and revealed deep white matter T2/FLAIR intensities in the pericallosal region, consistent with a clinical history of MS. MR orbits, C-spine and T-spine were unremarkable. She was started on Rituximab and has had one episode of optic neuritis requiring IV steroids but otherwise remains stable. Statistical Methods Enrollee characteristics were classified by gender and age of MS diagnosis groups. For categorical variables, frequencies and column percentages were reported and p-values were calculated using χ2χ2 and Fisher’s exact

tests, as appropriate. Continuous variables were tested for normality using the Shapiro-Wilk normality test along with histograms. Normally distributed continuous variables were reported using means and standard deviations (SD) and p-values were calculated using Welch two sample t-tests for two-group comparisons and one-way ANOVAs for comparisons involving more than two groups; otherwise, medians and first/third quartiles were reported [Q1,Q3] and p-values were calculated using Mann-Whitney U tests for two-group comparisons and Kruskal-Wallis tests for comparisons involving more than two groups. Statistical significance was set at p ≤ 0.05. Missing observations were reported and were excluded on an analysis-by-analysis basis. All analyses were done in R programming language, version 3.6.1 (R Foundation for Statistical Computing, Vienna, Austria). All graphics were produced using the R package ggplot2, version 3.1.1 (Hadley Wickham). Results Based on analysis of THA data of 2001 patients, no statistically significant gender differences were identified with respect to age at MS diagnosis, age at NMOSD diagnosis, or latency between these diagnoses (p-values = 0.428, 0.387, and 0.313, respectively). However, there does appears to be a significant positive correlation between age of MS diagnosis and time between MS and NMOSD diagnoses (Pearson’s correlation = 0.0739, p-value = 0.00094). When stratified by gender, this correlation appears to hold true in female patients (Pearson’s correlation = 0.0904, p-value = 0.00032) but not in male patients (Pearson’s correlation = 0.0147, p-value = 0.76324). Figure 1 shows that the delay in NMOSD diagnosis after a prior diagnosis of MS is relatively stable over various age groups among male patients but appears to increase over the age groups among female patients. Median latency to NMOSD diagnosis was longer by 63 days in women over 50 years of age vs compared to < 30 years of age. Median latency to NMOSD diagnosis in men increased by 3 days between men over 50 years of age vs < 30 years of age. As noted in the methods section, we present 4 illustrative cases that had typical MRI of brain findings consistent with MS but tested positive for NMOSD. In some instances, patients failed multiple DMDs which triggered NMOSD testing. Discussion Our study was based on the singular premise that some patients diagnosed with MS could have NMOSD. There is no way to ascertain the true numbers unless a systematic, retrospective analysis of cases is undertaken involving large numbers of MS cases reassessed for changing symptomatology and/or failure of drug therapies or both. No published data exists in the literature that recommends testing for NMOSD if the clinical findings and MRI of brain/cord changes suggest MS since the ‘diagnostic criteria are met’. Additionally, no systematic study has yet explored if tests for NMOSD may have to be repeated based on the immune status of the patient. We used a retrospective data analysis model to initiate a cross-sectional study to screen for Ab positive NMOSD patients who carried a prior diagnosis of MS. Our database analysis, confined to the period between 2009-2016, is limited given lack of availability of MOG Ab testing prior to 2017. Hence extrapolation of misdiagnosed cases of NMOSD that would include MOG Ab cases is not possible. We found that the delay in NMOSD diagnosis after a prior diagnosis of MS was relatively stable over various age groups among male patients but appears to increase over the age groups among female patients. We have no specific reason why this is but speculate that an established diagnosis is very difficult to dislodge even from a clinician’s perspective. As to why the delay was more pronounced in women, we speculate that acceptance of the status quo both by patients and physicians alike could be one reason; additionally, possible effects of gender bias, variations in disease incidence or discrepancies in follow-up may have contributed to this difference but such issues need to be explored. Median latency to NMOSD diagnosis was longer by 63 days in women over 50 years of age vs compared to < 30 years of age. Median latency to NMOSD diagnosis in men increased by 3 days between men over 50 years of age vs < 30 years of age.

The first patient in our study tested positive for MOG Abs almost a decade from the time of diagnosis. Key aspects of this case were that the patient had multiple drug failures and MS worsened despite use of multiple DMDs. Complicating the diagnosis was the MRI of brain that showed lesions highly suggestive of MS. In the

second case, recurrent ON, and contralateral ON that followed a decade later suggested it could be an MS mimic; MRI of brain showed lesions typical for MS two decades from diagnosis of MS. The patient tested positive for AQP4 antibodies. The third case in our series illustrates the fact that typical radiological features alone do not support a diagnosis of MS as MOG Ab testing was positive, showing a mismatch between radiological findings and Ab testing. The last case had typical MRI findings of MS on brain imaging, failed multiple DMDs and tested positive for AQP4. One of the pitfalls of a claims-based data analysis is the fact that no individual case analysis is possible. For instance, 2001/319,994 (0.62%) patients filed for claims for NMOSD after they initially filed for a diagnosis of MS. Since MOG Ab serum testing became available only in 2017, the numbers from the database perhaps represent only those AQP4 Ab positive cases misdiagnosed as MS. An interesting feature that is significant of our small case series is that the diagnosis of NMOSD was far removed from the index date of diagnosis of MS. This delay indicates that an MS diagnosis may have to be revisited depending on clinical symptom evolution even if radiological features are typical for MS. It is plausible that a diagnosis of MS based on McDonald criteria could be correct but changing phenotypic features may require reconsidering the diagnosis. This calls into question whether a diagnosis of MS is a fixed entity or needs to be changed based on evolving, new data although we have no data to support such a premise. Failure of multiple DMDs in MS could be an additional clue to consider alternative diagnoses to MS and this could be one area of research for the future. We would like to emphasize the fact that a diagnosis of MS cannot be made without strict application of McDonald criteria in the context of symptoms that suggest a demyelinating syndrome. Misdiagnosis can stem from incorrect application of the criteria to atypical symptoms such as fatigue or generalized weakness, for instance. No prior study has suggested that AQP4 or MOG Ab status needs to be tested in cases that have typical clinical and MRI findings for MS and we have attempted to address this question. The data is suggestive but larger datasets need to be evaluated to confirm or refute our findings. The ever-expanding criteria for diagnosis of NMOSD now include core characteristics that include ON, acute myelitis or area postrema syndrome, acute brainstem syndrome, acute diencephalic or symptomatic cerebral syndrome (Wingerchuk et al., 2015) and not restricted to recurrent ON, bilateral ON or LETM. The clinical phenotype features have expanded the diagnostic criteria of NMOSD but the possibility of highly specific and sensitive biomarkers becoming central to the diagnosis of NMOSD even if MS is the clinical consideration needs to be explored. As for false-positive MOG Abs in serum, the jury is still out since conformational epitopes on the extracellular domain of MOG are pathogenic and it is not unreasonable to conclude that deciphering false-positive MOG Ab status is a work in progress with no clear consensus. From a neuropathology perspective, the presence of MOG Abs is characterized by MS-typical demyelination and oligodendrocyte pathology involving complement and antibodies (Peschl P et al., 2017). Detection of AQP4-IgG antibody can be missed if CSF and not serum is used for antibody detection, contributing to delay or missed diagnosis of NMOSD. Surprisingly, CSF as the only sample submitted for analysis grew to 20.18% in 2015 from 2.37% in 2007, suggesting that testing for AQP4 Ab testing was suboptimal and erroneous, based on published literature (Majed et al., 2016). In the detection of MOG-IgG in serum, Mayo Clinic Laboratories reports a specificity of 99.6%, a positive predictive value of 95.5% and negative predictive value of 78.8% indicating that serum is the preferred choice (Waters et al., 2019). One other caveat in testing for AQP4 or MOG Abs is the fact that testing may have to be repeated in 3-6 months as per the recommendation of the Mayo Clinic Laboratories, particularly when patients are immunosuppressed or when clinical suspicion is high. The key aspects of diagnosis of MS rely on clinical, imaging and laboratory evidence (Polman et al., 2011; Thompson et al., 2018). In particular, imaging findings have allowed earlier, more sensitive and more specific diagnoses of MS to be made (Brownlee et al., 2017). Key radiological features that distinguish MS from NMOSD include the location, size, shape, configuration and age of lesions – in MS, the typical locations are

periventricular, juxtacortical/cortical, infra-tentorial or in the spinal cord. By contrast, lesions in AQP4 Ab positive NMOSD are typically localized to peri-ependymal regions rich in AQP4 antigen; hypothalamus, fourth ventricle, periaqueductal, optic chiasm, thalamus and hypothalamus are some of the common sites involved (Pittock et al., 2006). However, such radiological delineation is not always clear-cut. While certain clinical presentations such as bilateral optic neuritis or area postrema syndrome suggest NMOSD, no symptom is pathognomonic. As our cases demonstrated, lesion location and distribution alone do not establish the diagnosis of MS. Lesions that look typical for MS could have NMOSD positive antibodies challenging the theory that MRI lesion distribution helps define either disease. For instance, 27% of brain lesions in patients with NMOSD were suggestive of MS but no study has pointed out the opposite - that the diagnosis of MS may have to wait despite classic lesions suggestive of MS and that testing for NMOSD be required prior to a diagnosis of MS (Matthews et al., 2013). Lesions in the corpus callosum have been described in 12% to 40% of patients with NMOSD making it almost impossible to predict if NMOSD or MS is the diagnostic consideration just by evaluation of ‘typical’ lesions to separate the two entities (Chan et al., 2011; Kim et al., 2010; Nakamura et al., 2009). In the spinal cord, lesion length and asymmetric location can be useful markers in differentiating MS from NMOSD. Cord lesions typically are < 3 segments in MS; however, MS can also have long cord involving lesions and conversely, NMOSD can have cord lesions that are < 3 segments causing clinicians to suspect MS (Huh et al., 2017). Another confounder is the fact that the timing of MRI may influence lesion length – a short lesion detected within the first 24 hours may evolve into a longer lesion in 1-2 days and unless this radiological change is considered, NMOSD could be missed (Asgari et al., 2013). Cord lesions by themselves do not necessarily point to MS or NMOSD although > 3 segment length involvement implies longitudinally extensive transverse myelitis (LETM), one of the core clinical features of NMOSD. The impact of guidelines is skewed owing to outliers but the availability of assays for AQP4 and MOG Abs can potentially alter MS diagnosis if used in the proper clinical context and done even when typical symptoms and radiological changes suggest MS. It remains unclear if MOG Ab disease is part of NMOSD or a separate entity. Some advocate that MOG Ab disease may not be part NMOSD but others take the opposite view (de Seze, 2017; Jurynczyk et al., 2017; Zamvil and Slavin, 2015). Clinically, MOG Ab disease is typically monophasic, affects children predominantly presenting as acute demyelinating encephalomyelitis (ADEM), has no ethnic predilection, and probably has a better prognosis. The lesion distribution in brain is non-specific in its pattern. It causes ON and TM more frequently and no specific differentiating radiological or clinical markers that separate it from MS are known (de Seze, 2017). Since MOG Ab testing became commercially available in the U.S. only in 2017, cases that were previously diagnosed as MS may have to be revisited depending on appropriate clinical circumstances. There are several pitfalls with our study findings – it is retrospective, baseline MRI brain data were uniformly unavailable in our cases, and testing for NMOSD was only performed for involvement of bilateral optic nerves or poor drug responsiveness. The utility of NMOSD testing as a prerequisite for diagnosis of MS was not evaluated. In conclusion, it is apparent that clinical and radiological criteria by themselves are inadequate to separate MS from NMOSD. The application of McDonald’s or Wingerchuk’s criteria may not separate MS from NMOSD given overlapping clinical or radiological findings in ON, TM, or brainstem syndromes, among others (Thompson et al., 2018; Wingerchuk et al., 2015). Therefore, more research done prospectively in larger datasets is needed to know if NMOSD needs to excluded first even when a diagnosis is highly suggestive of MS. The authors report no funding and have no disclosures. No conflict of interest is reported by the authors. AU contribution section Jagannadha Avasarala : Conceptualization, development to the idea, database evaluations, case review, authorship and review of manuscript, corrections/edits. Paige Sutton: Review of cases

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Figures Figure 1. Latency to NMOSD diagnosis.

Box plot displaying the number of days between original MS diagnosis to NMOSD diagnosis for each patient. These data were then separated by age group and sex (n = 1,579 female; 422 male). The boxes display the second quartile (Q2) and third quartile (Q3) range of the data and the center lines denote median values. Outliers are depicted as individual black circles.

Figure 2 showing the top panel from case 1 and the bottom panel from case 2. Typical MRI features of MS on FLAIR images can be seen.

Figure 3 – showing representative images of brain from case 3 (top panel) and case 4 (bottom panel), respectively, of MRI of brain images highly suggestive of MS.