A MARTÍNEZ, HOST:
Actor Christina Applegate was diagnosed with multiple sclerosis five years ago. It led her to retire from acting. On Tuesday, Applegate said she had been misdiagnosed. MS is a chronic neurological disorder where the immune system attacks the protective covering of nerve fibers. It causes headaches, fatigue, vision problems, slurred speech and issues with mobility. For more on this, we called Dr. Michael Kornberg. He's an associate professor of neurology at Johns Hopkins University. Doctor, I mean, how could a misdiagnosis like this happen?
MICHAEL KORNBERG: So misdiagnoses, when they happen, can happen because, No. 1, there's no one single test for MS diagnosis. It's not like getting tested for strep or flu where there's a test, it's either positive or negative. It is a combination of having typical neurologic symptoms and then having other findings like typical abnormalities on a brain MRI, sometimes finding in spinal fluid. And so other conditions that have neurologic symptoms and also cause abnormalities on a brain MRI can lead to a misdiagnosis.
MARTÍNEZ: Wow, OK. So I'm wondering, how frequently does this happen?
KORNBERG: So it varies from study to study. Typically, the range that is cited is from 5- to 20%, depending on the clinic that is - that's investigated.
MARTÍNEZ: OK. And one more thing on this because, you know, five years of thinking that you have multiple sclerosis, how do you know when it's misdiagnosed? How do you figure that part out?
KORNBERG: So that can vary as well. So sometimes it is a new evaluation with a specialist, and it's clear from a number of things, you know, from a history, from evaluation of the MRI or from just the evolution of the disease. New symptoms may occur that point you in a different direction.
You know, I know nothing about the specifics of Christina Applegate's case, but from what she mentioned, she mentioned a new technology. And I imagine she may be talking about new MRI technology that has come into practice within the last couple of years that has helped to differentiate between abnormalities on MRI that are caused by MS and abnormalities caused by other conditions.
MARTÍNEZ: So I was going to ask about other conditions because are there certain diseases that maybe people tend to think look like MS to doctors?
KORNBERG: So most common are other common conditions that can also cause some findings on brain MRI. And very commonly, it's actually migraine, which I do not think is what is going on with Christina Applegate, but migraines can be associated with transient neurologic symptoms. They can cause some nonspecific abnormalities on an MRI. Cerebrovascular disease, so people with high blood pressure, diabetes can have some nonspecific abnormalities, and a number of other things, including rheumatologic conditions. Things like lupus, rheumatoid arthritis can cause some nonspecific neurologic symptoms and also some nonspecific findings on a brain MRI.
MARTÍNEZ: OK. Now, she - Applegate has been saying for years that she has experienced all the typical symptoms of MS, and now she's misdiagnosed. So I'm wondering, where does that leave her? Is she at square one, or at least do her doctors and her have at least a base, you know, to kind of go off of?
KORNBERG: So I hope and I imagine that she has a great medical team, and they should have a base to go off of. So she articulated very well the distress that happens when there's a misdiagnosis. And clearly, she feels very frustrated like she's at square one because her answer was taken away. But I'm sure that there is a differential diagnosis, as we say. There's other diagnostic possibilities that her doctors have in mind that they are currently exploring.
MARTÍNEZ: All right. That's Dr. Michael Kornberg of Johns Hopkins University. Doctor, thanks.
KORNBERG: Thank you very much.
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