Manitol challenge

[Naturesvalley]

Has anyone had a manitol challenge before. I am having one tomorrow morning. Do not know what to expect and therefore I very nervous

[Homely2 Administrator]

I had one. You basically go in, they check what your baseline fev1 is, they then give you something and see if it effects your fev1, then they keep upping the dose to see if they can get an effect.

They stop when either the effect exceeds a certain amount or it has no effect.

It is all fine, but it is good to take someone with you. With me they provoked a significant asthma attack and just told me to go. They are meant to not let you go until they have stabilised you again.

Some people react and some people do not. The person who did my mannitol test said that most people did not react.

If you react very heavily in the first few goes, like I did, they then want to check if you have an Ilo, as well as or instead of your asthma.

If you do not react at all whatever the dose, it does not give them the evidence they are looking for to support your asthma diagnosis.

[Naturesvalley in reply to Homely2]

Had the manitol challenge. Coughing a lot since the test. Also have been more breathless. The main problem at the moment is a whopping headache

[Chip_y2kuk]

Yes, I've had mannitol and methacoline (same tests different irritants)

You go in and do spirometry, then they administer the irritant and do spirometry afterwards.... there are a number of rounds of irritant with increasing amounts of mannitol

FYI both tests I had the first round is a placebo and doesn't contain any irritant.

They are looking for a sudden drop in your fev1 of around 20 percent.. to confirm asthma.

I didn't react to either test, but am still under the severe asthma team who are *adamant* I do have asthma... ive also had a reversability test and didn't meet the required threshold for that either (5.5% and the threshold is 12%)

[ChromoneLover in reply to Chip_y2kuk]

Yes, I was also told that I was ‘not asthmatic’, but I can feel my airways constricting in response to grass pollen, if I am late taking my (inhaled Sodium Cromoglycate) medication, even though March is early for grass pollen - although I have noticed a small amount of flowering grasses over the past 3 weeks - which is enough to make my eyes itch, even inside my workplace!

[Chip_y2kuk in reply to ChromoneLover]

Yes I got Told the same a few times... however the team I'm under now are adamant I DO have asthma .... it just doesn't seem to present in the typical ways

[nmcv13 in reply to Chip_y2kuk]

I’m being investigated by Resp Consultant who currently thinks I have ‘cough hypersensitivity syndrome’ not asthma. Am thinking this will be the next test for me as all other tests negative for asthma despite being on Fostair, montelukast & fexofenadine and still having exacerbations usually twice a year needing steroids. Has anyone else had ‘cough hypersensitivity syndrome’ diagnosis?

[runcyclexcski in reply to Chip_y2kuk]

Chip, did they tell you to abstain from steroid inhalers, oral steroids and rescue inhalers before coming for the challenge, and if yes, for how long did you have to stop? To be honest, this part (abstaining) is what would worry me the most and becoming susceptible to other triggers (not just manitol/methacoline).

I also wonder what their plan is if one does suffer a serious attack. I always have an epipen with me which, I found, helps recover from an attack when rescue inhalers no longer help.

[Naturesvalley in reply to runcyclexcski]

I had to stop all medications for 72 hours before the test. That included the azithromycine that I take 3 times a week. I do not feel that great at the moment following the test. Coughing, a bit breathless and a monster headache

[runcyclexcski in reply to Naturesvalley]

Maybe once your medication builds back up you will feel better? 72 hrs w/o inhaled and oral steroids does not sound like fun, if you take them! Sorry for your ordeal.

Did they manage to trigger a reaction in you?

They also could have done a rescue inhaler test (to see an increase in lung function instead). This is what they did for me, since they did not dare do the trigger test based on the lung function at the time. That was enough for the asthma diagnosis.

[Chip_y2kuk in reply to runcyclexcski]

I've had mannitol, methacoline, and a reversability test last year... I didn't react enough for any of them.

[Chip_y2kuk in reply to runcyclexcski]

Yes did, a nurse called me from the department armed with a list of what I took and how long before the test I needed to stop them

To be fair when you go for the tests they are "well armed" two nurses in the room for both tests, epipen on the side, oxygen and salbutamol nebuliser ready to be loaded and used .... it all felt very safe and planned (even though I didn't react)

[runcyclexcski in reply to Chip_y2kuk]

Thank you, Chip! Looks like it was well planned, indeed. It's also interesting that they had the epipen ready in case things go south. I have been told off by A&E to not use the epipen in the event of an asthma attack. But since I found out about its use in peer-reviewed papers, I feel justified having it ready.

[Chip_y2kuk in reply to runcyclexcski]

Yes apparently there has never been a test performed that created a reaction so severe they couldn't reverse it... and i did ask (but I'd also googled it before I went so I already knew the answer)

As for the epi pen they where in a metal tray in both rooms ...i hadnt actually thought about it helping breathing but figured it would be for serious anaphylaxis and they where just making sure they where prepared

[ChromoneLover]

DearNaturesvalley,

I had a Mannitol Challenge test in (October) 2022. It involved sitting in a sealed box (controlled environment and air mixture), after some preliminary tests. Then, I was asked to put on a nose clip, and had to breath out through a spirometer mouthpiece. After checking my baseline spirometry results, the test was repeated, using doubling doses of the naturally-occurring sugar, mannitol, via a dry-powder inhaler. I was checked after each dose, which the respiratory physiologist stops when/if you get a reduction of 15% or more in your spirometry results (FEV1), or they reach the maximum mannitol dose. They usually do 4 doses, in total, with 15 mins for it to take effect before measuring the effect via spirometry.

The test takes up to 90 minutes in all, and is supposed to check whether your lungs are hyper sensitive/hyperreactive.

I hope this helps.

[Homely2 Administrator in reply to ChromoneLover]

Thank you chromone lover. My test was done by a healthcare assistant with no 15 minute gap between doses. I now understand the speed of my reaction after three doses or so.

[runcyclexcski in reply to Homely2]

***My test was done by a healthcare assistant with no 15 minute gap between doses.

It's remarkable that occasionally one can get a tech who does not know what they are doing...

[ChromoneLover in reply to runcyclexcski]

Dear Runcycleski,

The thing that impressed me most about the test was the dry powder inhaler used for the mannitol capsules - with one of those, we could have inhaled sodium Cromoglycate as dry powder, so no environment-threatening propellant or preservative needed! Such a shame that combination was never offered to us!!😥😢.

[ChromoneLover in reply to runcyclexcski]

I think the interval was up to 15 minutes, it was a while back, so could have been as little as 10 minutes, I don’t remember clearly now, but my test was done at King’s College Hospital (GSST), by an experienced respiratory physiology technician, who explained every step before he did the measurement or administered the mannitol powder.

[runcyclexcski in reply to ChromoneLover]

ChromoneLover, did you get a reaction to the alcohol, and if you did, how long did it take to develop and how did you feel? 15-min waiting periods make sense, this is how long it takes for me as well.

The mannitol molecule looks like glycerol x 2 :). Maybe it's a reduced form of mannose.

[ChromoneLover in reply to runcyclexcski]

Dear Runcycleski,

no,I didn’t get a reaction to mannitol: slight (transient) cough after one down from the highest dose - they didn’t bother with the maximum dose, but said I wasn’t asthmatic - not surprising, since the test was done in October, when there is no grass pollen about😑.

[ChromoneLover in reply to ChromoneLover]

…the mannitol tasted sweet: a bit like the propellant in my old salbutamol inhaler.