many people go years or decades with symptoms prior to getting officially diagnosed with ms often having their symptoms misattributed to stress anxiety or other conditions on the other hand according to a study done at ucla and cedars-sinai in los angeles about 18 percent of people diagnosed with ms are actually misdiagnosed and they have something else so an accurate diagnosis of ms is no trivial thing so today i will show you the official diagnostic criteria for multiple sclerosis as gandhi said a correct diagnosis is three-fourths the remedy let's have some fun these are the 2017 revised mcdonald diagnostic criteria for ms i got this from the national ms society website i'll include a link in the description below the man to the right is dr ian mcdonald the new zealander who originally came up with these diagnostic criteria a long time ago and they've been revised multiple times since and validated most recently in 2017. and before we go further i do want to warn that you should self-diagnose at your own risk as application of these criteria does require some clinical experience now to understand the criteria you're going to have to have a little bit of a background and understand the concepts of dissemination in time and dissemination in space let's start with dissemination in time let's say someone has a neurological event where they become confused and have weakness of the body and mri scans show inflammation of the brain and spine and then they recover and then they're stable for several years with resolution of all the lesions on mri scans in this person there's really no evidence they have a chronic disease the whole nature of ms as people get different symptoms at different times in other words there's dissemination in time it's not just a one-time uniphasic event as i described before by the way that story is more consistent with a disease called adam or acute disseminated encephalomyelitis next let's move to dissemination in space the nature of ms is that it affects different areas of the nervous system at different times in other words there's dissemination in space and dissemination in time so let's say someone has optic neuritis and then a few years later they have optic neuritis again and a few years later they have optic neuritis again but there's no evidence of any inflammation anywhere else in the nervous system the mri of the brain and spine are normal and they have no symptoms suggesting injury to those areas well that history isn't really consistent with multiple sclerosis it may be consistent with another disease such as creon chronic recurrent inflammatory optic neuritis so multiple sclerosis diagnosis requires both dissemination in time and dissemination in space of inflammation of the central nervous system next let's move to some of the spaces that ms can affect so this is an mri of someone with left optic neuritis you're looking at coronal images so slices through the face like this and you can see the brain here and the right orbit and the left orbit these are the extraocular muscles and in the center here is the optic nerve and you can see the right side looks normal whereas the left side looks inflamed and takes up the contrast dye consistent with optic neuritis this is an mri showing periventricular lesions lesions around fluid filled ventricles which are the normal spaces that contain cerebrospinal fluid you're looking at axial slice like this and these bright lesions are very characteristic periventricular lesions which touch the ventricles they often have an ovoid space a shape with clear demarcation between normal and abnormal tissue these are corpus callosum lesions you're looking at sagittal slices like this right in the center of the brain and so this is the corpus callosum that joins the two halves of the brains and the lesions often line up like this causing what's known as a white picket fence sign very typical of ms these are juxta cortical lesions lesions directly underneath the cortex so on t2 sequences the cortex looks bright and the subcortical white matter looks darker and these lesions right next to the cortex are juxta cortical lesions sometimes they have a u-shaped appearance known as u-fiber lesions very characteristic of ms here we can see a brain stem lesion a lesion in the posterior fossa the brain stem and cerebellum this is in the right posterior or back of the medulla typical of ms so you can see it in other conditions such as neuromyelitis optica especially right next to the fourth ventricle so it would be hard to say just looking at this image that this is ms for sure and finally in the spine and you're looking at sagittal slices through the neck the cervical spine like this so these are the vertebrae these are the discs in between and this is the spinal cord which should be dark but you can see this white lesion at the c3 level this is the c3 vertebrae and you can see with gadolinium contrast it does in fact take up the dye and look active so these are just some of the different spaces which would characterize dissemination in space inflammation in different parts of the nervous system the next concept you have to understand is the idea of a typical demyelinating syndrome and the idea is that people can have all sorts of neurological symptoms but they may be due to something else people can have vision loss due to glaucoma or numbness due to peripheral neuropathy and so we have to recognize what's a symptom that's typically seen in ms versus something that isn't so some examples would be optic neuritis inflammation of the optic nerve and this would typically cause pain symptoms such as pain in one eye and vision loss and there are specific exam findings associated with optic nerve i just have a separate video on optic neritis if you want to take a look another example would be transverse myelitis or inflammation of the spinal cord and this causes symptoms such as numbness and weakness of the limbs or bladder problems and i have a separate video on this and another example would be a brain stem syndrome lesions in the brain stem are often associated with clumsiness and double vision and there are many other demyelinating syndromes such as numbness on one side of the body or weakness onto one side of the body and the symptoms tend to be slow in onset evolving over several days and then they peak and they may recover and each syndrome is associated with certain exam findings in the criteria they also talk about the concept of an attack versus an objective clinical lesion so for the purposes of these criteria an attack refers to the symptoms reported by the person with the disease so for instance someone says that i had vision loss whereas an objective clinical lesion is what's discovered by the examiner by the clinician so this could be physical exam findings or it could be other ancillary tests some examples include visual evoke potentials which is an electrophysiologic test that looks for signs of optic nerve injury the idea you hear is let's say i have a patient that comes in and said you know a year ago i had an episode where i had pain in my left eye and vision loss but then it went away and i examine them and they have absolutely no signs of optic nerve injury i may be able to do this test visual evoked potentials and find evidence of optic nerve injury even though they clinically recovered and this would support the idea that those symptoms were in fact due to optic neuritis there are other tests that are no longer routinely used such as brain auditory evoked responses and somatosensory evoked potentials sscps these are no longer routinely used just for reference so finally we get back to the criteria and there are different criteria for each clinical scenario and i'll walk you through all of them the criteria are organized with the clinical presentation on the left and the additional data needed to make an ms diagnosis on the right and you'll see they have to fulfill the criteria of dissemination in space and dissemination in time so the first situation is someone who has two or more attacks typical of demyelinating syndromes with objective evidence that these actually occurred so someone has optic neuritis and they have clear exam findings typical of optic neuritis and later they have transverse myelitis with clear exam findings typical of the disease they would not need any additional evidence in order to make an ms diagnosis presuming there was no other neurological disease causing this in practice of course you would do an mri of the brain to make sure there are lesions typical of multiple sclerosis but what about a situation where someone had two attacks but maybe they only saw a doctor during one of the attacks so it's not a hundred percent clear if the prior attack was in fact a demyelinating event now clearly this is a chronic disease they had multiple attacks and so you know the dissemination in time criteria is met but what about the dissemination in space criteria well now they say you need additional evidence so one way to do this is to have a further attack or you could have an mri scan showing dissemination in space visually in other words having ms typical t2 lesions in two or more areas of the nervous system such as the areas i showed you before the paraventricular area juxta cortical or cortical lesions infectorial in other words brain stem lesions or the spinal cord or you could also add the optic nerve although sometimes it's difficult to see optic nerve lesions on mri now the key note here is ms typical a lot of people have white matter lesions on mri that aren't typical of ms for instance this mri shows small poorly demarcated lesions which are very non-specific and sometimes can be an incidental finding or associated with migraine headaches these are known as unidentified bright objects or ubos and they're very common in the general population also sometimes people can have vascular disease tiny infarcts in the brain associated with aging hypertension diabetes high cholesterol this is known as leucoariosis and this mri is really not typical of multiple sclerosis at all and so you can see mri is very important in the diagnostic criteria but you have to be able to interpret it and it could easily be confused and lead to misdiagnosis but what about the situation where someone has one reported attack but on exam they have evidence of two clinical lesions so let's say someone has optic neuritis and i can see they have vision loss in one eye and other findings but they also have a lot of numbness in the legs and brisk reflexes suggesting they have injury to the spinal cord but they didn't even notice those symptoms this is actually surprisingly common clearly this individual has dissemination in space in different areas of the nervous system but how do i know it's a chronic disease that requires treatment well that's why there are additional criteria and of course you can see these criteria are designed to prevent us from over diagnosing people with ms and subjecting people to unnecessary testing or even dangerous medication and so to meet the disseminated in time criteria someone could go on to have an additional attack or it could occur through mri so when a lesion is active on mri it often enhances or takes up the gadolinium contrast dye and so if we see that one lesion is enhancing and another lesion is not enhancing it suggests they occurred at different times proving it's a chronic disease another way to do this would be if someone was monitored with mri scans and they went on to have a new lesion on a subsequent mri scan and the final way would be through the spinal tap and so if on a spinal tap someone has oligoclonal bands or antibodies that are in the spinal fluid but not in the blood this is a finding seen in about 90 percent of people with multiple sclerosis according to these criteria this would fulfill the dissemination in time criteria making the diagnosis of ms now believe it or not it's also possible to be diagnosed with ms after having only one attack with only one clinical lesion now of course such an individual would meet neither the criteria for dissemination in time or space and would need to fulfill criteria for both so this slide is just a summary of everything i said before so for dissemination in space they would have to have either an additional attack which would actually fulfill both dissemination in space and time criteria or have multiple lesions in different areas of the nervous system and for dissemination and time they could have an additional attack or have both an active and non-active lesion on mri have a future mri with a new lesion or have a positive spinal tap now not everyone with ms has attacks at all a small number about 10 to 15 percent of people with ms have a slow insidious development of symptoms and this is known as primary progressive multiple sclerosis some of my patients tell me what's a relapse i've never had one and these are symptoms that are progressive from the onset some of the most common symptoms would be slowly worsening walking speed or clumsiness or sometimes cognitive impairment progressive visual loss is rare in ms but could rarely occur and so these are the diagnostic criteria for primary progressive multiple sclerosis the first is one year or more of progressive disability and often by the time people have seen a neurologist they've had symptoms for several years just because they're so insidious and people often recount that retrospectively it's been going on for a long time so we can't diagnose primary progressive ms after a few months it has to be at least a year and two of the following three criteria at least one brain lesion typical of ms two or more spine lesions typical of ms on mri or a positive spinal tap so two of those three criteria to be diagnosed with primary progressive ms so what about people who don't meet the diagnostic criteria for multiple sclerosis what do we call it then well i'll talk about a few different scenarios one is clinically isolated syndrome or cis this is when someone has a demyelinating event such as optic neuritis but they don't fulfill the criteria i just described i'll give an example let's say someone has optic neuritis and they recover but they don't have any other symptoms and their neurological exam is completely normal they have an mri scan which does show some lesions typical of multiple sclerosis but none of them are enhancing they all look old and there's no prior mri to compare it to and they've never had a spinal tap this individual would not meet the diagnostic criteria for ms but there is a risk they would go on to meet the diagnostic criteria later in fact studies in optic neuritis suggests that the number of mri lesions typical of ms is the best predictor of risk of multiple sclerosis in the future another scenario is radiologically isolated syndrome ris this is where someone has an mri for another reason maybe headaches or head trauma and they have lesions very typical of ms but they have no symptoms of the illness and no history of symptoms of course this person does not have ms symptoms are required to make a diagnosis of ms as i just described this is known as ris interestingly about 50 percent of people with ris go on to develop multiple sclerosis but 50 percent do not this is depending on the case series you look at the best predictor of the risk of getting ms in someone with rs is having mri lesions in the spine and of course the third scenario is that there is an alternate diagnosis explaining the symptoms such as peripheral neuropathy just to give one example so who exactly needs a spinal tap as you may be aware fewer and fewer people with ms are actually getting lumbar punctures or spinal taps to help with the diagnosis this is definitely a good thing it's an uncomfortable test and our mri scans are getting better and better usually showing characteristic lesions at the time of diagnosis however it can be useful in a few scenarios in my opinion for example someone who has a single attack of demyelinating disease such as optic neuritis but does not meet the diagnostic criteria for ms for instance the story i described earlier if that person had a positive spinal tap that would make the diagnosis of ms so it could be very useful another scenario is progressive symptoms someone who could have primary progressive multiple sclerosis but does not meet the criteria based on mri scan remember you had to have at least one brain lesion typical of ms and at least two spine lesions typical of ms now most people with progressive ms are going to meet that criteria but there are some exceptions and of course the final thing is someone who clearly has a central nervous system disease but it's not so clear that it's multiple sclerosis for example i saw a patient earlier that had both optic neuritis and transverse myelitis but their spinal tap was not consistent with ms and i actually think they have something else called neurosarcoidosis so in that case the spinal tap was helpful to work against the diagnosis of ms so i'm happy to answer any questions in the comments i know the criteria are a little bit complicated and obtuse of course i can't answer specific questions about your diagnosis so just keep it general and if you want to share your own diagnosis story or misdiagnosis story please post in the comments below or if you have suggestions for future videos