Wednesday, September 22, 2010

Hypokalemic Periodic Paralysis

I had a couple of questions the other day about Digger's disease and I realized that I had never addressed it head-on here, just mentioned it in passing in a couple of posts.

All of my kids have an inherited disease called Hypokalemic Periodic Paralysis (HypoKPP) which they inherited from their father, who inherited it from his father, who inherited it from his far back as anyone can research.

It affects 1 in 100,000 people statistically (unless you happen to inherit the lucky gene) and causes signs and symptoms ranging from periodic extremity weakness to full-on paralysis, sometimes involving the respiratory muscles.  It's what's known as an ion channelopathy, specifically affecting the sodium/potassium and calcium channels in the cells.  Potassium must be pumped out of the cell and sodium pumped in.  It's all a very complicated way to maintain homeostasis (or balance) within the body.  Calcium is the necessary ion for muscle contraction, without calcium to activate the troponin and tropomycin, which then allows the actin and myosin heads to be released, no contraction can occur.  When those channels don't work, it throws a monkey wrench into, well, pretty much everything.

In a family with HypoKPP, each offspring has the following chances or not of inheriting the disease:
  • 25% will inherit the trait and will exhibit signs and symptoms
  • 50% will inherit the train, but will not exhibit signs and symptoms, but may pass on the trait to their offspring
  • 25% will be home free; they won't inherit the trait, won't show any signs and symptoms, and won't pass it on to their kids
I knew that my husband had the trait (and exhibited all signs and symptoms) and expected that if I had kids, they would probably have the disease.  The degree to which patients are affected varies.  For example, Digger has mornings when he wakes up a quad, but Ashinator's disease manifests itself via muscle weakness and drop attacks.  Ash tends to recover faster from attacks than Digger, who can take days to fully recover.  Monster complained of muscle weakness when he was younger, but no longer seems to exhibit any signs or symptoms.

It's much, much worse in puberty, but can be brought under control in adulthood.  Digger currently controls his with an assortment of prescription medications designed to help control his potassium balance.  Ashinator and Monster have such mild attacks, that they don't take any daily medications and will take prescription potassium only during an attack.

I worry about him living so far away with his roommates because I've seen the worst of his attacks and they're not pretty.  However, he's managing them pretty well for now.

We've developed a pretty good sense of humor about the whole thing - in fact, Digger's got about a 10 minute routine in which he re-counts the story of the day Ashinator tried to move him from his bedroom to the couch using a skateboard.  If I can get him to let me film him telling it, I'll be sure to put it up.


Beth Zimmerman said...

Sounds terrifying but if he can deal with it with humor .... more power to him! And his VERY brave mama!

Mrs Mom said...

HYPP in horses is terrifying. Sure sounds like they have things under MUCH better control and understanding in peoples! Which is most excellent news for Digger, Ash, and Monster! ;)

He sounds smart enough to keep tabs on things on his own. And if not... well, Mom you are only a phone call away, right? Be strong girl. You taught him well.

GunDiva said...

Of course you would know about HypoKPP in horses :)

Much easier to manage in humans.

Mr. Daddy said...

Sounds scary, but if you get a free skate board ride outa it, it can't be all bad....Right?

Thank God for humor and people that get it...

Rachel said...

This makes much more sense after relating it to HYPP... though I never thought of it that way before.

Seriously - did that not freak him out the first time it happened? I can only imagine (well, I can imagine really good from the one time I was strapped to a backboard after they took my glasses away too... I was deaf, blind, and paralyzed... oh - and INJURED. I can only imagine Digger feeling that!)

Glad it's manageable. And I'd worry too, but that's what us moms do. Please, please get the skateboard skit on video!!!

Maggie said...

Sounds scary! I'm glad they're all managing well with it, but I'd be worried too.

I'd LOVE if he'd let you video it!