Lactate and HFI

[antonia]

Do you as HFIers experience increased lactate levels when you are having a reaction? Or, has anyone with children diagnosed with HFI been told lactate levels were high? 

I was told by new genetics doctor today that if my daughter had HFI (or FBPase Deficiency) her labs would show high lactate levels. Hers do not. Can we rule out HFI based on that?

I've read about lactate as an indicator of FBPase Deficiency but never for HFI.

Thanks for your thoughts or any input.

[colormist]

Since I recently was admitted to the ER during a fructose reaction, let me look up to see if they tested my lactate levels.

Well, shoot. They didn't check my lactate levels, which is strange considering they knew my liver levels were extremely high. But maybe testing the lactate levels wouldn't give them any additional information they didn't already know.

I looked up lactate levels and WebMD says, "Lactic acid levels can also get higher when the liver is severely damaged or diseased, because the liver normally breaks down lactic acid."

Honestly, I've not heard of anyone else reporting on that lactate levels in regards to HFI. Unless someone else on the board reports otherwise (feel free to chime in either way!), I would presume that you cannot rule out HFI just because her lactate levels were not high. I would also think that her lactate levels would be in a normal range if you were treating her with a fructose-free diet. Our HFI livers are rather normal when we're on the fructose-free diet.

[antonia]

I really want to trust what the docs say but I find myself more confused after our visit. I feel like diagnostically he was discussing FBPase Deficiency, not HFI. When I asked for clarification between the two he said they were essentially the same thing. He had a patient with FBPase Deficiency and referred back to her several times. He said that when she went hypoglycemic her lactate levels were ALWAYS elevated whether they were triggered by fructose or not. Although I don't know that this patient is on a fructose free diet, I believe FBPase patients can tolerate some fructose so she may not be totally fructose free.

Essentially we were told because lactate levels were not elevated she could not have HFI or FBPase Deficiency. This may be true for the FBPase Deficiency but I don't know about HFI.

He also said her protein levels were low and that if she had a fructose metabolic disorder that they should be high, not low.

So between low protein levels, normal lactate levels and negative results from the sequencing portions of her HFI and FBPase Deficiency DNA tests he does not believe there is any chance she has either.

[colormist]

Any chance you can get a second opinion? You might also be able to email Dr. Tolan to see what his opinion is on the correlation between high lactate levels and HFI. It's not something I've heard before so I'm not sure why your doctor wouldn't just run a simple genetic test to rule out HFI.

Dr. Tolan's page: www.bu.edu/aldolase/lab/dean.html

If he's unresponsive, his lab members might be able to respond: www.bu.edu/aldolase/lab/people.html

[antonia]

This is not to say I did not like this doctor because I did. He was much more investigative than our last geneticist. He spent upwards of an hour talking with us. Going over her labs from her last hypo incident, asking questions about her symptoms, how we manage her hypoglycemia at home, etc. There was also a dietician present at our visit and she sat through the whole appointment just listening. 

And surprisingly we we were not shown the door! He said she definitely had ketonic hypoglycemia (her ketones were extremely high, much higher than they should be even in the event of illness). And he had us do a blood draw for analysis while she's healthy so that we can compare results to times of illness. He wants to see if she is always high in ketones and, if so, said she could take medication to balance blood chemistry which might make her feel better. Not sure how I feel about having her take meds but appreciate the suggestion. He also will give us an emergency letter stating what should be tested in the event she goes clinically hypo again. We didn't get ANY of that with our last doctor. No investigation at all.

But when I asked, if not HFI or FBPase Deficiency, than why does sugar cause her to go hypo, the answer is basically, "I don't know". I do appreciate that as an answer as well but don't know that he believes us 100%. But he did not discount it either. Because we have been living with it for so long and managing her diet fairy well, I have to remind MYSELF how extraordinary our situation is. Palmera is almost 6 and she has never eaten an ice cream cone, candy bar, piece of frosting laden cake, etc. This is extraordinary. Not normal. I can only recall two occasions where she ate significant quantities of sweets and both these occasions were met with with massive bouts of vomiting. I think unless you live it it is really difficult (for doctors, family and friends) to comprehend. 

[lucky]

Hi Antonia,

I'm not sure if I'm going to be too much help here, either.

In our case, when we initially saw our Genetic's specialist, he mentioned that our son's liver had been "unhappy". What that means and to what degree, who still knows.

And, in hindsight, I'm not sure if that was documented info from earlier testing records, or... 6mo after converting to an HFI diet.

For us, using the HFI diet (and feeding our son on demand and checking his BS levels) for the 6mo leading up to our Genetic's appt helped tremendously.

*But the diet change was only done on approval of and monitored by our specialists. For safety.

But questions linger... As in, what labs were done before/after the 6mo of HFI diet/detoxing (and feeding on demand) and later, what was specifically seen as improved or corrected.

* You also altered your daughter's diet, so conceivably she may no longer be in an acute phase (for certain tests to show strain)... Perhaps?

In our case, our Genetic dr. was quick to commend us (and our pediatric specialist) for the diet transition and the improvement seen. However, he was also astute to note that after 6mo of healing, he could no longer expect to see certain markers (in blood work) as our son was no longer in an acute state. Smart man. I appreciate him to this day.

Anyhow, I wonder if this might be your case, also.

If a diet (and feeding time) is favourably altered, and a body is healing well and recovering, then... why would you expect to see catastrophic markers of illness? Unless that Lactate issue is always present, regardless. I don't know. Perhaps ask at you next appt?

* Were you given any direction, medically, moving forward?

Out of caution, my son was given an FBPase deficiency DNA test (after the negative HFI DNA test), and later, an in-hospital test called a "Fasting Challenge". The latter tests fasting tolerance -which is an issue with FBPase deficiency.


*With regards to fructose tolerance:

We were told that FBPase deficiency was like an "ugly cousin" to HFI as, under the right conditions, it can mimic it's symptoms and dangers. Very close in line to each other genetically... but not quite the same.

HFI has an issue with adolase B.
FBPase deficiency does not.

HFI's primary need is to avoid fructose.
FBPase deficiency's is an energy/storage issue.

HFI requires very minimal fructose for decline.
FBPase deficiency requires more for decline.

HFI has a natural aversion to fructose.
FBPase deficiency does not.

BUT...

The "ugly cousin" part is that FBPase deficiency can, in an acute phase, mimic all the properties/dangers of HFI (in addition to its own issues).

Therefore sometimes FBPase deficiency can look very much like HFI, but when tested genetically, it is not (as adolase B is fine).

This is where the mimicking is a huge problem.

FBPase deficiency's primary problem is with energy and storage issues. It's secondary, is that fructose is a catalyst in driving it into HFI type symptoms/dangers (when not longterm metabolically stable).

However, when FBPase deficiency is under metabolic control, there are reports that some find a fair amt of fructose (up to 2gr of fructose per kg) can be consumed, *although not recommended*. The reason is that all it takes is a little metabolic instability (fasting too long, illness, over exertion, growing etc) to start the slide into it's own metabolic issues. And if those are not promptly identified and corrected, another additional slide into HFI symptoms/dangers can also follow.

However...
In the case of each, HFI & FBPase deficiency, if proper dietary perameters are followed and optimal health is achieved and maintained -all is well.

And that's incredibly wonderful.

So...
I'm not sure if any of that helps. But maybe it addresses a couple of issues where you are seeing conflicting things?

[antonia]

Colormist, we have had HFI and FBPase Deficiency DNA tests done and they were negative. However, they only performed the sequencing portion of the DNA tests. There is also a deletion/duplication portion that could be performed. But, when I asked yesterday why can't we perform the other portion of the tests, I was told that it was not warranted. Because both copies of the gene (mother and father) must have mutations for a positive result they feel if the sequencing portion shows no mutations than the likelihood of both mutations being deletions/duplications is slim to none. Statistically speaking, most mutations are found in the sequencing of the gene. That's how it was explained to me. However, DNA tests are not diagnostic, and since Palmera acts like a HFIer and her symptoms have basically been alleviated by the HFI diet, I personally am not able to let it go based on negative DNA tests alone.

Thanks for those links. I think I will send Dr. Tolan an email. See if he has an opinion on lactate as an indicator of HFI.

[lucky]

Antonia,

Our Dr. also gave us a requisition form for specific testing in the event of any future serious illness. I very much appreciate that line of thinking. Luckily, we have not had the need to use it, thankfully. But at least I know what tests are time sensitive and would be needed in a time of crisis.

Regarding low blood sugar:

Has anyone ruled out a possibility of insulin issues? I know for years our son has been quietly monitored to make sure that this craziness wasn't somehow connected to pre-diabetes BS fluctuations.

For us.. once our son was again corrected by IV, healed through a more compatable diet, and his vitamin D deficiency dealt with (*so important to check for all with BS and metabolic issues especially)... he stayed healthy. And years later is able to handle a safe amt of fructose for his situation.

I would have not believed this would ever be a possibility had we not accidentally stumbled into "the needle in the haystack" for our son's situation.

On the note of being 6yrs old and never eating or tolerating any form of sweets...

That is incredible and really needs to be seriously listened to and absorbed as a huge clue to something.

Have any in-hospital tests been suggested or done to start excluding anything? As in GSD disorders, Fructose related stuff, BS issues, or even the "Fasting" test I mentioned earlier?

When we got to this level of specialist, our son had many many tests done to try and at least exclude major groupings of possible issues or disorders, if nothing else. Unfortunately, he even had a muscle biopsy to eliminate a potential issue at a Mitochondrial (cell) level. Luckily that also came back fine.

But... wow. In your daughter's case, were you given any future direction or next steps?

[lucky]

Antonia,

It took 6mo to get into our first Gentetics appt and 15mo for the Gastro dept. Because our son, by then, was already healing and responding well to an HFI diet, there was no need to go to extreme measures of having either a needle or regular liver biopsy. So as a cautionary approach, our specialists tried to identify issues through other differing tests, instead.

However... we were cautioned three things:

1./
Further cursory testing was important. Why? Because sometimes the amt of testing needing to be done in a life threatening situation is too great. Quite simply, sometimes there is not enough time in a dire situation. So do it while a child is stable and they have time, ahead of a catastrophe.

2./
Should everything show "neg" but a balance in health is finally restored, long term... THAT is success. And it probably only means that as of today's medical info and testing standards, there are things (about issues) that are still not known, or tested properly or tests or equipment needed have not been created yet. So, a child may have a very valid issue, but not yet labelled or fully understood. Best is to get to stability and consider that the ultimate in success. Sometimes we may just not (or not currently) get the answers we wish.

3./
And lastly, in our case, and with everything we know... if our son ever goes into a real tailspin again, they may want/need to do a liver (or needle) biopsy. Because then declining health and wellbeing will warrant it.

I'm wondering if your daughter is relatively healthier now...

Perhaps her not showing alarming or emergent issues is masking some of your valid concerns. If she is stable and improving, health wise, you should continue what you are doing (diet wise and observing). But only if it is approved by her specialists. However, I'm hoping that enough serious unanswered questions will warrant the dr's to continue to work through her health issues (and conduct tests) bit by bit as more info/patterns show. There are just too many unanswered questions, still.

Ours was a long journey, sorry to say. Try to mentally prepare yourself that yours might also be. It seems that those who are identified quickly through already identified DNA or testing markers are spared a long journey in testing. For the rest, resolution takes a little longer.

Try and stay strong. xo

Best,
Lucky

[lucky]

Antonia,

I just realized you mentioned an issue with protein levels. Perhaps ask about that.

I know when my son's DNA testing came back neg, some other major tests were needed later on. One of which was to rule out if protein was the actual aggravating issue. It was not. But it was explained that there are two sides to all of this: Carbohydrate disorders or ones involving Protein as an underlying issue (if I remember correctly).

And, at some point, even after having much success with the HFI diet, we ran into a bad hurdle. Our son drastically increased his physical exertion (in a 3x/week activity). In hindsight, we think it was just too much, too soon (although he originally felt up to it). It either rocked him metabolically (after a couple of months), or dehydrated him longterm (and then took him down metabolically). Either way, he crashed. And that was when he needed a good amt of hospital testing done in a cluster. After those, an additional in-hospital "Protein Challenge" was done. It's need was explained that sometimes issues don't arise unless some type of accidental taxing (like a change in diet with higher levels of protein -HFI) pronounces it to being seen more clearly.

Our son did not have this problem, but as an example, if our son ate an HFI diet (which automatically has a higher protein load because there is now less fruit/veggie as fillers), then the balance within the digestive system could have shown enough stress to tip into showing the true culprit all along -protein. If so, it may have only been more noticeable because of the drastic diet change (and exertion issue) pronouncing it.

Well, that wasn't our son's issue either as his test came back negative. But I appreciate it's elimination as a possibility. You really want anything potentially relevant to a child's declining health checked. And they were cautious but very diligent with testing. It was a stressful time, I tell you.

Interestingly, again, the only thing that corrected our son was an IV. So, I have a real appreciation for it, even though our son hasn't needed it in the last 5yrs.

Antonia,
I just thought I'd mention info about protein in case it comes up for your daughter. If you get an opportunity, I would ask what low levels mean (if anything) for her health. You just never know about these things.

And, I don't know if this helps, but my son also had high ketones when he was in crisis. But I think there are logical reasons for it, and mainly because at the time his stomach hurt so much when he ate that he was drastically reducing food consumption.

In the end, we think *clinical dehydration* brought on a lot of his further symptoms that time.

If you look into it as a possibility, among the regular and dangerous known issues with it, you will see it can also cause painful stomach aches etc.

Proper hydration (and chime) is paramount to proper digestion. Without, digestion can be excruciatingly painful. And, it can be the downward slide to selective eating (or not eating enough), to high ketones, BS issues, and then to metabolic distress (and seizures etc). Not pretty.

Good news is it is easily corrected if caught in time and proper levels of hydration and electrolytes are restored. It's scary how something so simple can be so dangerous if not in balance.

[antonia]

Lucky, all good points, all good questions.

Funny, this doctor used the same language, that something was making her liver "unhappy". Her liver enzymes have only been slightly elevated though, another reason he does not believe she has HFI or FBPase Deficiency.

Yes, this is essentially what he was saying, that if she had HFI or FBPase Deficiency, lactate levels should be elevated, regardless of the fact that she has undergone healing and symptom improvement since changing diet and feeding schedule just as you described. And, my questions are the same. Many of these diagnostic measurements are time sensitive. How do we know they were taken at the right time to be meaningful? I've read in the literature that during fructose challenge tests, that measurements of factors like lactate are not stable or long lasting. Once fructose has been processed blood chemistry returns to normal fairly quickly. I'm talking as quickly as an hour or two, not even in terms of days. So it seems to me that catching blood chemistry indicators can be tricky and negative results are not diagnostic unless monitored under a controlled environment such as a fructose challenge test.

He did not offer any kind of fructose challenge test as a future option either. When I asked how we could determine if fructose was causing hypo he said the only way was to give her fructose and see what happens. And by this he did not mean in a controlled hospital environment but at home. Not something I'm willing to do.

Follow up is to see him again in 3 to 4 months and review blood work again. See if she has any more hypo episodes in the mean time due to illness which would offer additional blood work to analyse and review. The idea of just waiting for this to occur again does not thrill me either. We have pulled her out of school because of her inability to fight illness without going hypo and being really sick for weeks/months on end. I'm not going to allow that to happen if I can help it. I just can't handle the constant fear illness anymore. I'm hoping for a diagnosis before the next school year. Catch 22, because it seems the only time we learn anything is when she gets ill.

When I listen to your story I tend to feel jealous in the support you received through your medical system in Canada. We've had a different experience here in the US. We were never offered guidance with diet, feeding schedule, BS measurement, etc. Doctors in the US won't offer treatment plans or recommendations unless there is a confirmed diagnosis to base them on. At least that's been our experience. Why that is is up for debate I suppose. Without getting too political, I'll just say it probably has something to do with the fact that our medical system is controlled by insurance companies. This environment is not conducive to investigative, good doctoring, in my opinion, doctors are held back by too many legal constraints, fear of being sued, etc. Had we not made changes to my daughter's diet on our own accord, I'm afraid she would still be unable to do much more than sit on the couch with a puke bowl at her side and watch television. That's the state we were in before the HFI diet. I have had one, maybe two doctors, commend us for managing her diet on our own.

[antonia]

Lucky, this doctor felt that low protein levels could be explained by the fact that when she was ill she was not eating well, not getting enough protein in her diet basically. One of the meds was actually to take a specific protein that she was quite low in orally. Can't remember what it was, will look for it. He said beef was a good source to get it from the diet. Palmera does not like beef as much as chicken and pork. Interesting. If you remember, what protein related disorders was your son tested for?

Palmera has had IV fluids 3 times now when she's gone hypo to point she can't keep anything down. Each time she received both dextrose and saline. She has never shown signs of dehydration but they always give her the saline anyway which is good. We also just had blood tests for basic vitamin and mineral deficiencies. Surprisingly her vit D was fine. We live in rainy, cloudy PNW part of the US, don't get much sun at all, so I was surprised by that. She does eat a lot of full fat dairy though which must help with the absorption of the fat soluble vitamins in general. Only deficiency noted was magnesium, it was slightly low.

[antonia]

This doctor did mention GSD as a possibility. However this particular type of GSD involves intolerance to fructose, sucrose and lactose. Palmera has no issue with lactose though. Based on that seems unlikely.

[christopher]

Hi there.

Just wanted to chime in on this as I have been wondering about lactate levels myself.

Starting off, I find it strange to hear your doctor say that HFI and FBPase deficiency are basically the same thing. As lucky has already stated, they are not.
Both conditions are inborn errors of metabolism, but they differ from each other.

The deficiency of Aldolase B in HFI causes the partially metabolized fructose (it is converted very efficiently and fast to fructose-1-phosphate) to accumulate, as the conversion is very fast, and the enzyme responsible for the next conversion in the process is defective. In my understanding the fructose, now in the form of fructose-1-phosphate, is then trapped in the liver (or other organ in which Aldolase B is used).

Fructose-1,6-biphosphatase deficiency on the other hand is really an error of gluconeogenesis. That is, the livers ability to make glucose from other substrates, such as proteins, fats, lactate, etc. As per my understanding the different placement of the enzyme deficiency in the gluconeogenic pathway, in difference from HFI, allows for the fructose-1,6-biphosphate (which is not metabolized sufficiently due to the deficiency of the -ase), to be converted into lactate using a slightly different pathway. This pathway on the other hand also causes glycerol to be excreted in the urine, as it also is accumulated along with lactate.

One of the studies I have read (and have stored somewhere) stated that glyceroluria is highly indicative of FBPase deficiency. Unfortunately I believe that this has to be tested for. I have not been able to find any clinical symptoms for glyceroluria. (Sorry, probably TMI: personally I have felt that there is something strange in my urine for a long time, but my doctors don´t seem to care or try to find out what it is. But, my urine is exceptionally foamy. Also, when I have investigated further on my own by poking around in a cup of urine with a cotton swab, there seems to be some sort of mucus in it, and it pretty much is that way all the time. I presume it to be the reason for the foaminess, but I have no idea what it is. Any of you know anything about this?)

Also, high lactate levels also occurs in the body when going through anaerobic exercise. Personally Ive had episodes in the past in which I have, out of the blue, had these sensations happen to me. Especially in my legs and calves. Lactate is an energy source for lots of different muscle tissue, and during exercise some tissues prefers metabolizing lactate. In exercise the accumulation of lactate in muscles cause them to stiffen. That is the same sensation I have had in the past, but without any obvious cause. Please let me know if this sounds familiar.

[christopher]

I have also considered actually doing a challenge test my self, if I cannot get my doctors to help figure this out. I have a friend who has a device that measures lactate, similar to glucose/ketone monitors that I can borrow. 

If I am not mistaken, ingesting enough fructose to become hypoglycemic will cause lactate to accumulate, but the lactate will accumulate due to the fructose not being metabolized completely by the liver - not by the hypoglycemia. As such, ingesting enough glucose at the same time should prevent any hypoglycemia from occurring, but elevate levels of lactate in the blood. So, it should be a lot safer than just doing a challenge with straight fructose - i.e. not managing the hypo.

[antonia]

Hi Christopher,

I can't say I've ever noticed Palmera's urine being foamy or containing any precipitates. On one occasion, when she was 3, her urine did contain crystals and was actually high in pH. The pH may have been what allowed crystals to form? But usually when she is hypo and producing ketones urine pH is low, not high. So, I'm not sure what the cause of this was. She was in for a stomach ache on this occasion but did not have nausea or vomiting with it, so the stomach pain must have been due to something other than hypo on this occasion.

I think what the doctor was referring to in saying that HFI and FBPase were the same was from a diagnostic perspective. In that since they both cause hypo much of the diagnostic chemistry is the same? Being that I don't have a medical background, I have to trust and put my faith in what the doctors say. However, I am going to contact Dr. Tolan for a second opinion. I'll let you know what he says. I have read a few pieces of literature that do mention lactic acidosis resulting from HFI... so I understand that it CAN occur, but does it ALAWAYS occur and is it time sensitive or easy to "catch" from a diagnostic perspective? Also it's unclear to me if lactate is the same thing as lactic acid? What happens when you have high levels of lactate in the blood? So many things I don't understand, so again I leave it up to the doctors. It does seem that lactate, glycerol and alanine are often mentioned as indicators of FBPase Deficiency, but I don't see the same mentioned as indicators for HFI. Our doctor indicated that high protein levels in general (not specific to alanine) was an indicator of BOTH HFI and FBPase Deficiency, as was lactate.

Something interesting I ran into while looking into glycerol in the urine was glycerol kinase deficiency or hyperglycerolemia. This condition also causes hypoglycemia, among a host of other symptoms that seemed to vary widely as did the degree of severity it could present with. If you have not already, you might want to check it out. It was very late when I was reading about it, but it seemed there were some muscular related symptoms similar to what you have described. But it was very late, and can't remember if those symptoms were only when in combination with other diseases/conditions that involved muscle function.

As for Palmera, I don't ever recall her expressing muscle soreness, though she is young and I don't know that she could express the feeling if she was indeed experiencing it. She has complained of weakness in the legs, especially when climbing stairs, but I have always thought that was more likely due to low blood sugar and a feeling weakness in general.

[christopher]

Lactate and lactic acid is pretty much used interchangeably. In my understand what happens when lactate is produced and released into the bloodstream (in any way the body does this, be it by anaerobic exercise or by the liver of a person with FBPase deficiency under the "right" conditions) is that the lactate loses a hydrogen ion, a H+, due to something-something with the charge of lactate vs. the pH of the blood. In any case, the result is that there will be an increase in both lactate and H+ in the blood, the latter of which is what causes the acidosis (H+ causes pH to drop).

I too feel that I have read about lactic acidosis in relation to HFI as well as FBPase, but I am not sure it always occurs or if that is time sensitive from the diagnostic perspective.

Thanks for the heads up on GKD. I have looked into it a bit, but have not felt it fitting my symptoms all that well.

I have something interesting to tell you guys about in regards to lactate, though. I have run a small experiment on myself and the results were pretty much as expected. Disclaimer: do not attempt this on your own - talk to your doctor before even considering experimenting on your own!

What I have done is that I have gotten my hands on one of these lactate scouts - a device similar to the glucose monitors that enables you to take a measurement of your blood lactate levels from a small drop of blood taken from your fingertips. This is the one I have used www.ekfdiagnostics.com/lactate-scout.html

But first some information about lactate: "The normal blood lactate concentration in unstressed patients is 0.5-1 mmol/L. Patients with critical illness can be considered to have normal lactate concentrations of less than 2 mmol/L. Hyperlactatemia is defined as a mild to moderate persistent increase in blood lactate concentration (2-4 mmol/L) without metabolic acidosis, whereas lactic acidosis is characterized by persistently increased blood lactate levels (usually >4-5 mmol/L) in association with metabolic acidosis.[1, 4]" -- from emedicine.medscape.com/article/768159-overview (Not too good of source, but who cares...)

My plan was to do several measurements of blood glucose and blood lactate in the morning after rising from bed, but before eating breakfast. First I wanted to establish baseline measurements. Then an intervention which I suspected would cause a small reaction in these measurements but not be serious or dangerous to myself. I did this by ingesting a couple of dietary supplements that I have reacted to in the past, that I know contain sorbitol which is converted into fructose in the liver. In intervals of approximately 20 minutes from that intervention I did glucose readings, and 1 hour after the intervention I was to do a lactate measurement. If my metabolism of sorbitol is normal, there should be no increase in lactate. Vice versa in the case it should be abnormal. During the time of the readings I did not do anything in particular besides browsing the internet. 

Here are my results:

1. Intervention= -5 minutes  (First measurements/baseline readings - done in the morning first thing after getting out of bed. The other readings were also done in the fasted state - besides the intervention) 
- Glucose 5,2 mmol/L
- Lactate 1,7 mmol/L (I believe this is a little bit high, as I believe fasting levels of lactate are normally lower than 1,0 mmol/L. Not sure though.)

2. Intervention= +0 minutes  (Consumption of the dietary supplements containing approximately 500mg of sorbitol, along with 1 large glass of water) 

3. Intervention= +20 minutes
- Glucose 5,6 mmol/L

4. Intervention= +40 minutes
- Glucose 4,9 mmol/L

5. Intervention= +60 minutes
- Glucose 5,1 mmol/L
- Lactate 8,7 mmol/L (wow, this is way beyond normal. This is comparable to what 800m track runners experience when competing.... I was wondering if there might be something wrong with the device or the testing strips, so I did another test, but using blood from a different hand and finger;
- Lactate 4,0 mmol/L (a lot lower, but still a lot higher than normal, and indicative of something strange going on. Worth mentioning in regards to the difference between the measurements is that the first measurement was taken from fingers on my right hand that I have some strange issues with, I get spasms in them that are a little similar to tetanic contractions. The other measurement, from the other hand, was taken from fingers in which I have no such weird issues. Not sure if this means anything, but I thought it strange.)

6. Intervention= +90 minutes
- Glucose 4,5 mmol/L
- Lactate 4,0 mmol/L (still high, and taken from the same finger as the last time. If I had had more testing strips available I would have done more lactate tests, but I had a limited amount.)

So, it would definitely seem like my intervention caused a substantial spike in blood lactate. As for my glucose readings, they did not really tell my all that much, and anyhow I did them mostly to stay on top of things should I have become hypoglycemic. Safe to say that there is definitely something going on with how my body metabolizes sorbitol (or rather the dietary supplements I took, as they also contain other ingredients.). 

Second disclaimer: Even though this worked out for me, it might not go that well for you! Do not attempt the same without the assistance of your doctor! 

[antonia]

Just an update. I finally reached out to Dr. Tolan about lactate production in relation to HFI. He did write me back and while he's not a physician, and thereby cannot give medical advice, he did inform me that lack of lactate production does not rule out HFI. He explained it is similar to elevated liver proteins in that it "may or may not occur in an acute way and coincident with hypoglycemia." In short, there is no way to rule out HFI based on blood tests for lactate and/or liver enzymes.

[rysmom14]

Just thought I would throw my 2 cents in. My son had high lacte levels when he was in metabolic distress. they have marked his medical record as being allergic to lactated ringers. and now that i am typing it, I am wondering what the thought process is behind that. I will let you know when I go to his next appointment in a few months.

Another comment is that since HFI is so uncommon, and GSD are more common, my sons Genetic Dr. was not specific in telling the nutritionist what he could not have and recommended a vitamin that contained sugar. the name "fruity Vits" sounds off to me so I asked her to read the ingredients and she told be that we were good because there was not carbohydrates. i insisted and she read one of the ingredients as sucralose. I almost hit the floor. When I told her he couldnt have that because of HFI, she said that she was told to recommend a vitamin that was safe for the other GSD take. This could have been so terrible. No one thought to specify the unique challenges with HFI. So while I consider it a win that the Dr. are able to make some comparisons to similar conditions, they are just that.... similar, so to have them be more sensitive to the small things that make each condition different.

[antonia]

Thank you rysmom. That's scary that even with a confirmed diagnosis you have monitor your medical team like that. I don't really feel that our geneticist acknowledges the effect sugar has on our daughter. While he acknowledges we have a metabolic problem, I noticed he stated on our emergency letter that Palmera could not tolerate high protein intake. Which is not true. What I told him was that one of the times she went clinically hypo was after a high protein and high fructose meal with no starch or glucose based carbs included (to help combat the hypo). It was a meal of eggs, bacon and half a kiwi fruit that did that to her. Eggs and bacon on their own, without the fruit, would have been just fine. So, yes, because he's not really familiar with HFI, seems it's just really hard for him to comprehend or even hear what I am describing to him. Not a problem with protein, problem with sugar! Argh.

I would be interested in what you find out about the lactate ringers. Anything I can learn that I can bring back as a question at our next appointment. If I keep probing maybe someday we'll have answers.