"We present a patient with findings of subacute combined degeneration (SCD) in the setting of a mild B12 deficiency, with a normal methylmalonic acid level."
Although this will not be news to old-timers here, it's important to note that, contrary to the statement in the paper's conclusion, there is NO gold standard to diagnose B12 deficiency. Anecdotally, I had a low-normal B12 and did not have a raised MMA value but I had significant neuropathic damage, recovery from which took almost a year of intensive treatment.
Some health providers checking MMA will regard it as a gold standard which can be used to rule out a B12 deficiency. This is NOT the case and is a misunderstanding of the diagnostic power of the test. If you have a B12 deficiency with neurologic symptoms but your healthcare provider insists its not B12-related because your MMA is not elevated, it's important to know this information.
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Technoid
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Very interesting Technoid. thank you. My MMA was not elevated. It was, I believe, the reason they did not want to diagnose the PA, even with a positive IFAB. Maybe that is another reason why I had to take another IFAB test which came back undeterminable. And also because they had started me on injections. So my MMA was this:
Methylmalonic Acid
Normal value: <=0.40 nmol/mL
Value
0.14
I don't really know how to read this as the numbers in your article are different. I think it is low.
I should clarify that a raised MMA (excluding other factors that could cause it), does provide good evidence in support of a B12 deficiency. The point is more, as Cherlyclaire alluded to below, that MMA not being raised cannot be used by itself to rule OUT a deficiency. It would be quite expected for effective B12 deficiency treatment to reduce an elevated MMA to normal levels. Raised MMA NOT responding sufficiently to treatment could indicate functional B12 deficiency.
I really do not know. I am not saying for sure that is what happened, but I know that they have told me I have several scary and serious things, only to say later that I don't, due to other test like MMA. Yet I feel terrible every day. so what is it? Why run these tests if no one knows how to read them or connect the dots. When I asked about some of the diagnosis, they have told me that the MMA doesn't validate sjogren's or Multiple Myeloma. After reading this article. It made me feel that because my MMA was low, they could be misdiagnosing things or dismissing something serious. I am not well. And no one has any answers. After 3 plus years I have learned a lot but I also still have just as many unanswered questions and nowhere to turn for answers. But isn't that all of our stories? Unfortunately, I think it is.
EllaNore yes, your MMA was low, which is normal and wouldn't (by itself) indicate a B12 deficiency (but as we understand from the article, MMA being normal (not elevated) is NOT sufficient to rule out B12 deficiency, despite what some clinicians think)
My experience with doctors is that they don't listen and they don't believe anything you say. They don't even write it down. The disparity between my medical notes and what I said to the clinicians I saw is astounding. You would get a completely different and completely mistaken picture of what happened to me if you just read my medical notes.
They even omitted to mention their critical misdiagnosis and their dosage recommendation which caused most of my trouble. Communicating with them eventually become pointless and a waste of my time. If I see them again, it will hopefully be in a court of law while I sue them for malpractice.
I agree with you 100%. If there was a such thing as a thousand percent I would agree with you that much. 44 years of egotistical doctors not listening, writing down things that are not true, things I didn't say, one doctor making a diagnosis and then the rest of them, from there on out, running with it. All one doctor has to do is mention anything mental at all and that's it. You'll never be taken serious. Doctors put me where I am today. If I could sue every doctor I had I would, but there is no recourse for me or most of us. I hope you do sue and get every penny you deserve.
MMA test: Better for a raised serum MMA test result to be used as another method of ruling in those with suspected B12 deficiency symptoms but no low B12 serum result as expected. Confirmation, rather than in-range result being used as a means to rule out the possibility of B12 deficiency.
When my MMA dropped down into range (205 nmol/L, with range 0-280 nmol/L ), after three years of frequent B12 injections, I didn't feel any difference or notice any changes. This, the 6th test, taken by DNA experts, proved only that my MMA test results for the previous 5 tests (350 - 400 nmol/L) had been abnormally raised - and not just "normal for me", which is the direction that the locum haematologist was starting to veer toward. So for that reason alone, worth it.
Given that I was having EOD injections then, total serum B12 was obviously high, active B12 also high and homocysteine normal.
"Nil else" found, as they say. Oh, except blippy folate and ferritin levels, osteoporosis of the spine, osteopenia of the neck, patchy gastric metaplasia and a flattened mucosal pattern at D1 and D2 (duodenum), angular cheilitis, ventricular ectopics and saliva duct strictures, that sort of thing. Things I can live with.
The things I really can't live with so easily: cognitive impairment, memory loss, word-finding problems, irrational anxiety and mood-swings, sensory overwhelm and confusion. So I still need 2 B12 injections a week to keep my symptoms under control. No change there.
What difference did all the tests make for me ?
My GP got me the first of my MMA tests, and based on that result and elimination of other possibilities, gave me a functional B12 deficiency diagnosis, confirmed by the testing laboratory, and requested EOD injections for me.
Otherwise I would have just continued to deteriorate on the one B12 injection every 3 months - and no doubt get told by an irritated nurse:
"Well, it works for all my other B12 deficiency patients." .
If there was an actual 'Gold Standard' then we'd all be using it. [Here we go again] The Schilling Tests were very good, but still had drawbacks, and could be misused. But they're now history.
The test did actually cost a fortune, required the patient to be B12-replete before we started and required two trips to hospital. Plus it included a 1mg injection of B12 before we started, to saturate the transcobalamins and stop the body from storing and utilising the radioactive B12.
Clinical Judgement is still the best answer we have, and let's have more of it.
This diagnostic flowchart from a UK health document suggests doctors should consider continuing treatment if patient has responded to treatment (meaning symptoms have improved) even if results of secondary tests eg MMA, homocysteine, Active B12 (holotranscobalamin) are normal range.
And of course, MMA test results should be showing as within normal range once B12 injections have replenished B12 sufficiently to clear any MMA backlog. So would be expected to have cleared by the time loading injections were completed - and return a normal result.
There would be little point in switching to "maintenance" injections prior to optimum results re improvement of symptoms, methylmalonic acid's function being to form a link with the B12 introduced and taking it to depleted cells and tissues.
This is quoted from the materials describing the journal.
[Start quote]
About Neurology
Neurology is the official journal of the American Academy of Neurology.
Vision: Neurology will be the premier peer-reviewed journal for clinical neurology research.
Mission: Neurology will publish outstanding peer-reviewed original research articles, editorials, and reviews to enhance patient care, education, clinical research, and professionalism.
[End quote]
So presumably this article went through a rigorous process of peer review. Sad commentary on the understanding of B12 deficiency diagnosis among the peers of the authors, and by the editor of the journal.
Too bad we are allowed to see only the abstract and not the article. I would like to see the sources referenced for the "gold standard" assertion.
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