17 May 2010

Science and health

Ordinarily a subject line like 'science and health' would be followed with a note about how science was doing good things for health, or how we understood more about health because of some recent research. Instead, it's time for some reflections about looking from a scientific perspective at health issues that you might have.  Two things prompt this.  One, you're unsurprised to hear, is that I'm having a nuisance that has contributed to not being here.  The other was email I received recently about running with diabetes.  On the latter, it's important to note that you can run with diabetes.  You have to be more thoughtful and attentive about it than the usual beginner.  But it can be done.  That article was written by a runner with diabetes (Rob Carr).  The diabetes prompting him to start the running.

Whatever is at hand, you rapidly get taken to a chance to think scientifically.  My take being, remember, that science is about understanding the natural world.  Your body is a pretty important part of your natural world.  A different aspect of the consideration is that I think science, and thinking scientifically, enrich your life.  At least it does mine, and I think it's for reasons you can share.

I confess at the moment one of the attractions of the science is distraction from my body.  What happened is that I caught something in my eye.  Blown hard enough that it scratched the cornea.  It turns out that a scratched cornea is very painful, so looking at the anatomy and physiology of the eye is helpful for distracting me from that.  (Seriously: One thing that helps with pain management is aiming your attention hard on something else -- reading books, knitting, your left big toe (assuming that the pain is somewhere else, maybe the right.))

It turns out that there is very little guidance on exercising with diabetes.  So you have to do your own experimentation to understand what's going on and what you need to do, what you can get away with doing, and what you definitely cannot do.  It's imperative because exercise is an important part of managing diabetes, particularly adult-onset diabetes.

Running with diabetes requires one end of science, the 'what happens if I do this?'.  You need to pay a lot of attention to what happens to your blood sugar before, during, and after the run.  This was one of Rob's major experiences -- that he could indeed determine what was important to managing his diabetes.  If he collected enough data.  For diabetes management this means your test strips (if you need strips) and in general, measuring your blood sugar and assessing how you feel.

How you feel could be fuzzy.  If that's what it is, write that down.  Back in high school, I described something in chemistry class as being fuzzy.  Some of my classmates, but not the teacher, took exception to me using a normal word like 'fuzzy' to describe something.  They figured that I should use something long and 'scientific' -- meaning, really, something that nobody would understand.  Especially if you're writing notes for yourself, but also for doing science, it's important to use words that will be understood.  The scientific vocabulary is weird because it's trying to be clear -- to the people in the area at least.  But clarity is the aim.  For my class's purposes, 'fuzzy' was a perfectly good word.  Everybody had a similar idea of what 'fuzzy' meant.  For your own notes, use terms that you're going to remember what they meant.  If 'chumbly' is such a term, great; use it. (One of my physical therapists used that one.)

A different sort of science is 'what goes on here?'  For my eye situation, the start was having a small speck of something, probably metallic, blown in to my eye on a windy Saturday (8th of May).  Ordinarily the eye produces tears to wash away things.  Either the tears weren't enough, or the wind was strong enough to blast the speck in to the cornea.

The cornea is the top few layers of cells in your eye.  It's so thin that the cells can get their oxygen by just letting the oxygen molecules bounce their way through the layer of corneal cells.  They need this because there are no blood vessels in the cornea.  Oxygen has to come from somewhere.  Ordinarily that'd be the blood vessels, but running blood vessels across the front of the eye would interfere with being able to see.  So our bodies found a different solution to feeding the cells.

On the other hand, the cornea does have nerve cells so that you can feel pain when you have something caught in your eye.  That's part of what triggers the tear response.  Your body generally isn't very subtle.  Pain is the sign that something is wrong.  If tears aren't enough to remove the obnoxious foreign body, you can also normally remove the body by pulling your upper eyelid over the lower lashes and brushing off the obnoxious against your lower lashes.  It could take a few tries to get this to work.  But usually between tears and brushing off against the lower lashes you can take care of anything.

Sometimes, as happened with me, you can't. One thing I learned along the way, incidentally, is exactly why you shouldn't rub your eyes.  The constructive reason that you think about doing it is to encourage your eyes to produce tears that will wash away the obnoxious invader.  The reason you shouldn't is that you can drive the obnoxious invader in to your cornea and/or scratch the invader through the cornea.  I'd never previously heard it put that way.  I'd heard, of course, that you shouldn't rub your eyes 'it will only make it worse', but not just how it will do so.  I didn't do this, but never previously had understood why.

Ultimately I went to the emergency room because the pain was that high, and neither tears nor trying to rub the invader off against my lashes was working.  First time I'd ever gone to an emergency room. 

Digressing a minute: There were a few 'rules' where I grew up.  One was that 'real men don't admit to pain'.  It's likely, according to the ophthomalogist I saw Friday (14th), that the only reason I can see out of my right eye is that I don't believe that.  As I said, pain is your body's sign that something is wrong.  He was horrified that I hadn't come in earlier (like Monday, the 10th!).  You know something is seriously wrong when your doctor is saying 'Oh my God!' every few seconds.

The normal good news about a corneal scratch is that the cells are replaced very quickly.  24-72 hours is the turnover time.  That makes sense, if you think about it.  The cornea is exposed to the insults of outside world (obnoxious gases, chemicals, scratches, ...), and doesn't get a blood supply to rebuild itself.  One way of keeping the cells there healthy is to replace them very often, like 1-3 days.  Which takes us to the next phase of my learning.

After 24-72 hours, I was still having pain.  While I don't entirely believe my childhood's area's attitudes about men and pain, I did somewhat.  I was still having pain.  This turned out (Friday) to be because I still had something embedded in my cornea.  The doctor(s) seemed surprised I was still walking around.  The first one I saw verified that I had something in my eye, but he didn't have the right tool (a drill) to remove it.  He also said I seemed to have an exceptionally large 'cup' in my optic nerve, which is normally a sign of glaucoma.  (It wasn't a great week for good news.)

But the first doctor arranged for me to see a second doctor, who did have a drill.  He also (of course, and reassuring to me) did his own check of what was going on.  That included seeing the exceptionally large 'cup' in my optic nerve.  But, more immediately, it meant seeing the obnoxious bit of metal lodged in my cornea and removing it.  The speck which had been tormenting me for almost a week was so small that my wife could only see it with a magnifying glass.  I can just barely see it with my unaided eyes.  It's maybe 0.1 mm (100 microns, 1/250 inches).  Hard to imagine how something that tiny was causing so much pain.

So Saturday was fine.  Much less pain, and the eye was doing its healing process.  This meant recovering from having a hole drilled out of the cornea.  For having something to think about other than the week of pain, I started thinking about how the healing process might work.  Two ideas came to mind.  One was that the cells adjacent to the hole would sense the hole and divide until they had filled it in.  The other was that the eye was just always producing new, healthy, cornea cells at the edge (where there is a blood supply) and then pushing in towards the middle (where they'd be the oldest and dying, or, in my case, they had been forcibly removed).  It turns out that the eye builds from the edge inward.

So a fun bit of learning.  But Sunday was not so fun, as the pain levels shot up as soon as I woke up.  The new cornea cells turn out not to be firmly seated on the layer beneath.  So it can happen, and probably did, that as the eye dried out at night, the thin layer of new cells over the hole were torn off.  That wouldn't have been pleasant.  But it also turned out that the tiny bit of metal had probably been capping off some bacteria.  The tiny, marginally visible, bit of metal had probably carried along some bacteria -- a few microns, thousandths or tens of thousandths of inches.  Once it was removed, the bacteria started growing, meaning I developed an infection.  The infection meant the pain levels started up.  Again fortunately I didn't believe in 'ignore the pain'.  Called the Dr. on Sunday (he'd said it would be ok) and he saw me, saw the infection, and prescribed appropriate antibiotics.

Fortunately we didn't have to engage in more scientific learning.  If it hadn't responded to the antibiotics, the next guess was fungus.  Fungi are a lot less responsive to medication, and would have required taking a sample (off my eyeball!) and growing it in a dish to see which one of many fungi it was.  If it had been fungus, though, it would probably have been a Psuedomonas.  When the Dr. said that, I laughed.  I know very few genuses, and this is probably the only fungus genus I know.  I know it because Psuedomonas (synringii) are thought to be important for producing rain.  I'll take that up at a later date.

In the mean time, I'll just repeat the advisory that pain means something is wrong, and you should figure out why.  Once you figure out why, address the problem.  If I'd fully followed the notions of my childhood area, I probably wouldn't be looking out of my right eye.  Ignoring pain is stupid!

3 comments:

davidp said...

You have my sympathy with the eye.

I've been there twice with corneal scratches. The first was an old beanstalk that snapped and got my eye while weeding - guaranteed fungal infection, took a week of antifungal drops, and it happened on the weekend before starting a new job. 1 hour at work followed by a week off!

Something actually embedded in the cornea sounds very painful. My second corneal scratch was much more straight forward and almost better in 5 days.

I generally react rapidly to eye issues - sight is too precious for delays.

Does type II diabetes affect glucagon production or effects? I've seen the effects of too much insulin/too low glucons for type I diabetes (a work colleague spending hours sitting effectively stunned ; an aquaintance who died from it). My work colleague found that he could not add two numbers involving a carry when he was low on blood sugar (17+24=31)- he got us to use it as a test of whether he was O.K. A similarly simple test someone can administer after exercise might be helpful.

Tracy P. Hamilton said...

Had a speck of sawdust get caught in the eye - it felt like a boulder. Not too much pain, but promptly went to our eye hospital. Not many cities have one, but Birmingham, AL is a great place to get sick. :)

Penguindreams said...

all:
as of last Wednesday, I had a clean bill from the eye doctor. No further pain.

davidp:
I don't know about glucagon.

My understandings sit only with glycogen and glucose. The brain runs on glucose only (versus muscles, which can also burn protein and fat), so when blood glucose levels get too low, it makes sense that mental arithmetic and other such activity would be impaired. Certainly that's a routine experience among long distance runners (where long means over 15-20 miles, 25-30 km). In my long runs, it gets harder to compute my pace per mile in my head, once I've passed about 15 miles.

If someone is diabetic, it is particularly important to identify some clues like this that friends and colleagues can apply. Mental arithmetic, tongue-twisters, and rapid speech, are three I've heard of being used.