ITP in Children

Remember when you were 7 and had a favorite color? What was it?

Mine was always red.

Along those lines I still have a few favorite things, especially in science. For example, my favorite type of blood cell is the platelet. That’s right. Better than the white or red cells. More interesting than the non-specific genre of plasma. I’m kind of laughing at myself that I actually have a ranking in my mind about blood cells, but such as it is, I figure you guys are pretty cool and won’t judge too much, so looks like today’s the day I’m admitting my internal hierarchy publicly.

Platelets are the tiny, spiky stellate warriors that help our blood to clot.

Also called thrombocytes (thrombus = clot, cyte = cell), these cells circulate around and do their job without drawing a lot of attention to themselves: they aren’t really a part of fever (I’m looking at you, white blood cells) nor do they make medical students’ lives a nightmare by having different types of hemoglobin that bind to oxygen differently (big eye roll, red blood cells). They are produced similarly to other blood cells in the bone marrow but have the most swell progenitor name: the megakaryocyte (25 cents!). Platelets are activated by a cascade of chemical reactions that signal them to rush to the site of an injury and halt the bleeding process. They rally as well in supportive roles when the body is in a state of inflammation, so often when the white blood cells (which fight infection) are elevated, the platelets rise too in solidarity. Just so darn likable, no?

I am a bit of a realist, so I’m not immune to the fact that sometimes platelets don’t act right. And there’s a fairly common disorder in children that I want you to know about that is precisely this situation. I bring it up now since it often comes on after a viral illness, and we are entering into big time viral season. So let’s proceed.

First, the name. Immune thrombocytopenia (ITP).

Also known as idiopathic thrombocytopenic purpura. Handy that both of those have the same initials. That’s some name, huh? Sounds complicated, but it actually just means low platelets because the body is destroying its own platelets too rapidly. Sometimes due to certain medicines or a recent illness, the body is triggered to make anti-platelet antibodies that attach onto the platelets and signal the body to attack them. This results in a low platelet count. Weird, right? It happens to perfectly healthy kids. And it’s not cancer. Many times people think that all blood disorders are linked to cancer because some blood disorders ARE cancer (leukemia), but not this one. ITP affects between four and eight per 100,000 children under age 15 each year. There’s an acute and chronic type of ITP, with acute ITP affecting younger kids more. It usually occurs just once and often goes away within a few weeks to a month or two. The chronic form lasts for more than six months up to over a year, can affect any age, and occurs more in females.

Normal platelet levels are usually over 150,000. As the platelets decrease in number, the potential for bleeding increases. Fortunately, the platelet count has to get fairly low in order for this to happen, but I’ve seen platelet counts of less than 10,000; and when this happens, kids usually need to come into the hospital to get a special IV infusion of a steroid or an Immunoglobulin medicine to keep their immune systems “busy” and to be observed closely so that significant bleeding (i.e. head/brain) does not occur. Eventually this autoimmune process simply goes away all on its own.  Usually if the platelets are “medium-low,” say 20,000-50,000, children are able go home and be watched there with close outpatient follow up with a pediatric hematologist. A level of over 50,000-75,000 usually doesn’t require any intervention, just patience as the platelet levels slowly recover on their own.

So what does this disease look like on the outside?

Usually the first sign is easy skin bruising or bleeding- reddish/purple spidery web-like or dotted blotches (petechiae) appear on the skin, and sometimes nosebleeds or gum bleeding/oozing can be seen. Larger bruising is referred to as purpura. I always ask if there has been a recent viral illness because for some reason those are frequently the culprit in starting off an episode of low platelets. Most of the time kids with ITP look like they are perfectly well except they are covered in these petechiae, which is often a giveaway for the diagnosis.

A quick check of the platelet levels in the blood gives away the diagnosis immediately. What’s interesting is that this isn’t a production problem, it’s a destruction problem; so that when the bone marrow of kids with acute ITP is examined there are plenty of early platelet cells; they just get destroyed once they get kicked out into the circulating blood. (Part of the reason why white blood cells didn’t qualify as my favorite, though they are quite swell in many scenarios.)

Alright. So, if the diagnosis is ITP and the platelets aren’t dangerously low, just moderately low, then what does it mean?

We know if the platelets are super low (below 10,000) then the risk of bleeding is high and treatment is warranted, but if they are just “medium low” then during this time of acute illness high contact sports like football and lacrosse need to be prohibited. For younger children the environment needs to be made as soft and safe as possible to avoid possible opportunities for minor trauma which could cause bleeding of any sort. It’s really important to stay connected with your child’s doctor during an ITP course to discuss what sorts of activities he/she can be cleared for. Avoiding head injury when platelets are low really is of paramount importance.

As dramatic and even as scary as ITP sounds and can be, the outlook for kids who have it is quite good. Most commonly it’s a one-time occurrence, but I think it’s important to raise awareness about it because it can sneak up pretty quickly, and when it shows up as just some unusual looking painless, non-itchy red dotted rash it may seem like no big deal, but it really does need close medical attention.

So keep an eye on your kids’ skin, mouths and noses, especially during the few weeks after they’ve had a run of the mill virus. The body can occasionally do some quirky things when it’s in infection-fighting mode, and even all-around, general do-gooder platelets can wind up as collateral damage every now and again.

They’re still my favorite.