Brief Answer:
Suggest verifying Vit. B12 levels

Detailed Answer:
Good evening to the concerned parent posting this question on behalf of their daughter. My name is Dr. Dariush Saghafi and I would like to share my thoughts on how one might proceed based upon your presented information. I am a neurologist who treats patients frequently with these very symptoms and I often see folks with mostly normal lab and diagnostic testing results.

I'm almost mortified when something comes back abnormal because then, answers easily pop out most of the time! Now, why can't all of life's problems just SHOW THEMSELVES in simple lab tests, huh???? LOL!

At any rate, you state that for the past 2 years your 25 year old daughter has been experiencing worsening symptoms of numbness in the hands and legs, headaches, fatigue, and memory loss.

Your report is that a CT of the brain as well as in-depth laboratory testing were found to be normal with the exception of a single B12 test which is documented as 300 and which was said to be low but of no clinical consequence per the doctor's opinion.

It would be helpful to know what the range of normal values are according to the laboratory that ran her B12 levels. Typically, levels of B12 in our laboratories are considered low when they run below about 220. Having said that, there is a criterion referred to as the XXXXXXX Criteria for B12 testing which proposes that all B12 levels under 350 in patients suspected as having symptoms of neuropathy or mental status changes should be further investigated in order to VERIFY that indeed levels are within normal range as suggested by the reference range.

Sometimes we can be fooled by a value (such as 300) into thinking that even though it's low in the range it's still normal and therefore, doesn't merit further testing. I tend to always follow the XXXXXXX criteria for B12 levels and if I consider testing anybody for this vitamin and receive levels under 350 I automatically move to the following tests:

1. Methylmalonic acid in serum
2. Homocysteine in serum
3. Homocysteine in urine

In the case of the above tests what we are looking for would be significant elevations above the upper limits of normal which would then, indicate that even though the laboratory stated value of B12 is within the reference range, in fact, from a biochemical perspective it is actually in low stores within the body.

Admittedly, I believe that a 25 year old woman is far too young to be suffering from B12 deficiencies but if she has any type of GI disturbance such as IBS, GASTRITIS, PEPTIC ULCER DISEASE, or CROHN'S DISEASE. Or if there is a significant alcohol usage history then, Vit. B12 deficiency is at definite risk. If she carries none of the above risk factors then, the only other way she could be deficient would be through extremely poor dietary intake.

I might also suggest the following tests be performed (if not already done) to complement the verification of her vitamin B12:

1. Vitamin D (Total), D2, D3 in serum
2. Folate in serum
3. CBC w/differential to check for anemia
4. Thyroid function tests to include FT4, TSH, and FT3
5. Cortisol levels in serum at random as well as 6am
6. Hemoglobin A1C
7. ANA, ESR, C-REACTIVE PROTEIN, Lupus anticoagulant
7. Urinalysis
8. Microalbumin in urine

If the above labs were to all come out perfectly normal then, I may consider obtaining an MRI of the brain (with gadolinium) in search of demyelinating lesions although I think her clinical picture is less compelling for that sort of thing and especially taking into consideration that she is 2 years into the picture without apparent involvement of either motor or ambulatory capacity. Still, I would order these tests in the interest of completeness.

I hope the above information gives you some more direction to discuss with your daughter's doctor and that he may be able to explain to you why he agrees or disagrees with these additional tests (if they've not yet been done).

In my practice and in my hospital patients who still fail to demonstrate significant abnormalities with these laboratory or MRI tests I would then, recommend your daughter be sent for consultation with our neuropsychologist to discover more in-depth data about her cognitive and behavioral status so that further steps could be determined in the diagnostic process.

With the hope that you find some valuable answers to this incredibly long ordeal and that your daughter's good health return soon.

If you agree that these data have been helpful and timely then, I would greatly appreciate your written feedback with a STAR RATING. I'd also ask that if there are no further questions or comments for me to review that you CLOSE THE QUERY from your end as this will show the managers of these boards and questions that we have adequately and satisfactorily addressed your concerns so that the case may be registered and filed as complete.

This case required 56 minutes of physician specific time for review, research, and documentation of the final draft for envoy.

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