Thunderstorm Asthma
24
August

By Adem Lewis / in , , , , , , , , , , , , , , , , , /


When I woke up I was struggling to breathe.
I was gasping. It was very, very, scary not being able to
breathe. It’s akin to trying to breathe through a straw. You just can’t get enough air in. At 4am on the 25th of November last year,
Peter Jones knew he needed urgent medical help. And he wasn’t the only one…
That night, 90 people arrived at the emergency department of The Alfred Hospital in Melbourne,
with severe respiratory problems. There was actually quite a lot of mayhem in the hospital when I got there. There were a lot of people there. Peter and the other patients were caught up in an epidemic of thunderstorm asthma – a rare phenomenon that’s caused by a perfect storm of weather
conditions and airborne allergens. As you’ll see, it’s an explosive mix. Cenk Suphioglu identified the role ryegrass plays in Melbourne’s thunderstorm asthma epidemics. So that’s the culprit? Yes, this is the culprit. This is ryegrass. You can see the anther popped out to release the pollen so on days like this, during hay-fever season,
they actually pop out and they release the pollen which gets picked up by winds
and taken for long distances. In fact, during a thunderstorm, half a tonne
of pollen per hectare can take flight. But while it may inflict hay-fever in urban areas, something else is needed to trigger
thund erstorm asthma. Pollen itself, even though we don’t see it with the naked eye, is too large to penetrate the lower airways. So it actually gets trapped at the epiglottis; about here. So for something to penetrate the lower airways –
to cause asthma – you need smaller, micronic particles less than five microns in diameter. So what are these smaller particles? And how are they released into the air? …Cenk’s team answered that by studying what happened when ryegrass pollen was exposed to the moisture in thunderstorms. After it’s been in contact with water,
you can see that it’s actually ruptured. It really does look like it exploded out of that weak point. It is under pressure and the rupture will actually
release these contents like a projectile. So it will actually allow it to get airborne. This osmotic shock causes the pollen grain to release about seven hundred starch granules. Each one is coated with & contains major allergens. And they’re small enough to penetrate deep into our lungs. On a day which had no record of rainfall in the previous 24 hours we had approximately
1000 starch granules per cubic meter of air sampled. But as soon as we had rainfall that actually went to more than 54,000, so that’s actually
more than a 50 fold increase. The phenomenon has been recorded in Australia
and overseas, but Melbourne has the dubious honour of being
known as the thunderstorm asthma capital of the world with three recorded epidemics since 1987.
[recorded in 2011, before the 4th epidemic in 2016] Melbourne is particularly a hotspot for this because when these pollens are being released, (they) are picked up by northerly winds and all of the growth is in the northern parts of Victoria,
and the northerly winds pick them up and bring them into the metropolitan area where most of us are, and then you have the perfect model system
for thunderstorm-induced asthma. So, thunderstorm asthma is an allergic reaction
to grass pollen and you don’t have to be asthmatic to get it. In fact, seasonal hay-fever sufferers like
Peter are most at risk. I think because it was the first time I’ve had
an asthma attack, I am now aware of asthma more than I was before.
But I certainly didn’t take it seriously. You need to take it very, very seriously.


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