The rate of misdiagnosis of MS around the globe is roughly a quarter. We are so focused in making an early diagnosis in MS that before we know it, it’s a runaway train. Sometimes, even the best of us need to eat our words, and admit to having a made a mistake.
The diagnosis of MS is not easy; how many of you have googled non-specific symptoms and come up with MS as a potential cause? The McDonald criteria for the diagnosis of MS, has notably struggled to balance sensitivity with specificity over the years, but in 2016 introduced the idea of only having one T2 lesion in at least two of four locations on MRI (juxtacortical, periventricular, infratentorial and spinal cord) for dissemintation in space; a move that would clearly increase the rate of misdiagnosis. Nonetheless, it improves the rate of pick up by 72%, versus 60% and 47% rates from the 2005 and 2001 McDonald criteria, respectively.
Last week, a study of new referrals to two large academic centers (teaching hospitals) UCLA and Cedars-Sinai found that the rate of misdiagnosis was 19 and 17%, respectively. A majority of these misdiagnosis were made by a neurologist rather than a non-neurologist, simply because a neurologist is more likely to receive these referrals.
How do you decide what is not MS? The clinical presentation maybe atypical (for instance, a normal neurological exam) and the MRI head scan may have radiographic red flags, including normal head scans, pointing towards other diagnosis. The most common misdiagnosed group were headaches/migraines. A group that also receive the most MRI head scans.
The co-existance of other autoimmune disorders is also more likely to lead to misdiagnosis, indicating that they pose a challenge for clinicians (e.g. abnormal CSF findings, including OCBs) or unduly raise concern of MS.
“This suggests that MS diagnosis may stem from misapplication of MS diagnostic criteria in patients for whom they were not intended” -Kaisey et al.
Having said all this, misdiagnosis of MS can result in considerable risk to the patient – 72% were prescribed a DMT, while 28% were exposed to risk of progressive multifocal leukoencephalopathy (PML) in this cohort; not to mention the psychological harm, and the financial burden.
Mult Scler Relat Disord. 2019 Feb 2;30:51-56
Incidence of multiple sclerosis misdiagnosis in referrals to two academic center
Kaisey M, Solomon AJ, Luu M, Giesser BS, Sicotte NL
Background: Multiple Sclerosis (MS) specialists routinely evaluate misdiagnosed patients, or patients incorrectly assigned a diagnosis of MS. Misdiagnosis has significant implications for patient morbidity and healthcare costs, yet its contemporary incidence is unknown. We examined the incidence of MS misdiagnosis in new patients referred to two academic MS referral centers, their most common alternate diagnoses, and factors associated with misdiagnosis.
Methods: Demographic data, comorbidities, neurological examination findings, radiographic and laboratory results, a determination of 2010 McDonald Criteria fulfillment, and final diagnoses were collected from all new patient evaluations completed at the Cedars-Sinai Medical Center and the University of California, Los Angeles MS clinics over twelve months.
Results: Of the 241 new patients referred with an established diagnosis of MS, 17% at Cedars-Sinai and 19% at UCLA were identified as having been misdiagnosed. The most common alternative diagnoses were migraine (16%), radiologically isolated syndrome (9%), spondylopathy (7%), and neuropathy (7%). Clinical syndromes and radiographic findings atypical for MS were both associated with misdiagnosis. The misdiagnosed group received approximately 110 patient-years of unnecessary MS disease modifying therapy.
Conclusion: MS misdiagnosis is common; in our combined cohort, almost 1 in 5 patients who carried an established diagnosis of MS did not fulfill contemporary McDonald Criteria and had a more likely alternate diagnosis.