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A Case Overview:
The Case of the Disappearing Lesion
“Lesions Come and Lesions Go -
but Mostly they Come” ~Quix
Known lesions showed on MRI, and now they are missing -- GONE!
The MRI took it. Did the MRI capture it properly?
The Brain took it. Has the brain reabsorbed the lesion?
MS did it. Is this a case of typical MS?
January 6, 2009 Julie (Sarahsmom46), a concerned MS forum member reports:
We have discussed disappearing lesions on follow-up MRIs, but I still do not understand how and why this happens in MS? My neurologist said it can happen in MS and that's all I could get out of him. By the way, I do not have a definite diagnosis of MS, only "possible" MS.
My question: Say I have 7 lesions on MRIs from 7 months and 4 months ago. In my last MRI a few weeks ago, 2 lesions “disappeared.” This disappearing act came 3 weeks after a 3-day IV Solumedrol and steroid taper.
It has been a challenge to find anything I could truly understand on the web about this as the information was way over my head.
Thanking you in advance for you response.
January 8, 2009 Lead Detective (Quixotic1) reports:
First, yes, lesions can disappear from the MRI in MS, and it happens all the time. I describe how it occurs in the first Health Page, "How MRIs Show Lesions in MS." In brief, a lesion (a T2 hyperintense white matter lesion) first demyelinates and shows up on the MRI for as long as it is in the damaged state. The body tries to repair the damaged myelin (fatty coating around the nerve). The attempt at remyelinating is often quite successful and the lesion may disappear from the MRI.
In reality remyelination is not perfect in healing the nerve, so the nerve signals in the repaired nerves are usually still slowed. The symptom that lesion may have caused may go away, but may reappear when the nerve is stressed - like with getting overheated (remember the hot tub incident?) or with fatigue.
This remyelination is why people with classic, milder RRMS can have a relapse and then apparently return completely to normal during their remissions. Even people with more severe disease still have some lesions that disappear. So disappearing lesions are quite normal in MS. Lesions come and lesions go - but mostly they come.
About the resolution of lesions with Solumedrol. The answer is that solumedrol does not heal lesions. If it did they could treat MS with steroids alone. What the steroids do is relieve any inflammation that may be causing acute symptoms. Ideally you would think that all lesions with new inflammation will "enhance" on MRI, but if the inflammation is minor/small, they might not be seen as enhancing. Your lesions disappeared 3 weeks after the steroids. In general this is too long a time to say that the Solumedrol is responsible for the disappearance. Steroids take effect within 24 hours and do their thing pretty quickly. If you felt better during and after the IV steroids then we can safely say that some of the inflammation around lesions was helped by the med.
Question and Answer
1. Are the lesions that apparently disappeared really gone-gone or just smaller or hiding in there still?
2. Are there any other neuological conditions that you know of that have disappearing lesions like that found with MS lesions?
There is no way of telling what truly has happened. The lesions may have shrunk so that they are no longer visible to the MRI machine, but maybe could be seen by a more powerful MRI machine. OR they may have healed so well that the area of the lesion now looks just like normal-appearing white matter. Within the same person both things could be happening with different lesions.
Remember, though, that when the brain repairs damaged myelin the repair is not perfect. Though the nerves may look okay, they typically still transmit their signals more slowly than they did before the damage. This slowness may show up as the reappearance of old symptoms when a person gets overheated.
A good example of this is when a bout of optic neuritis heals. Optic neuritis is caused by a lesion of demyelination on the optic nerve. The lesion may remyelinate and the visual symptoms will go away. Any lesion that was seen on the MRI will also disappear. However, when you do a VEP (Visual Evoked Potential) on that person, the result will still be abnormally slow. Remember the VEP measures the speed of the visual signal along the optic nerve and then to the visual center of the brain. After optic neuritis you typically find the nerve signal remains slowed even after healing.
~Many other disorders can have lesions that heal. These include the autoimmune disorders, infections, demyelinating disorders like ADEM and others. However, I think that the pattern of appearing and disappearing lesions is a strong pointer toward MS.
~Not all people with MS will have lesions disappear. Also, not all lesions any of us have will eventually disappear. Some are too badly damaged and cannot be remyelinated.