Today we visited a pediatric hematologist to see if she could come up with a reason for small boy's nose bleeds (I was also sort of hoping she would come up with a reason why he would not be able to get a mechanical valve). Small boy had some fancy pants blood work done a few days ago, and we went in so she could explain the results.
It turns out that there is a reason why small boy's nose bleeds last so long. Blood has lots of different ingredients: some of them help carry around oxygen, some of them help fight germs, and others help plug any blood vessels that get leaks by forming a clot. There are lots of different ingredients that help blood clot. Small boy has a problem with two of them.
First are the platelets. Platelets are like sticky sweet gum seed pods. When a blood vessel gets a hole in it, they stick to the edges of the hole...and then they stick to each other and form a temporary plug. Small boy's platelets are not as "sticky" as expected. That means they form a less stable plug more slowly than expected.
Then there is factor IX. Factor IX is one of many ingredients that create the "glue" that coats the platelets after they form that plug. The "glue" helps strengthen the plug made out of the platelets. Oliver has less factor IX than expected. This means his platelet plugs have a harder time staying stuck together after they form.
We don't know why small boy's platelets are less sticky than expected or why he has less factor IX than expected. His unusual heart anatomy may be making his platelets less sticky. He may be using up more factor IX to make up for his less sticky platelets (Use more glue to hold the flimsier clots together). He may have a mutation in the gene that codes for factor IX. We don't know.
What we do know is why he has such long nose bleeds. We also have more information to think about as we consider how to proceed with his next surgery. There is a medicine (DDAVP) that may help when he gets long nose bleeds, but overall, having an explanation for why he gets the nose bleeds does not prevent him from getting nose bleeds...or from getting a shiny new mechanical heart valve for his birthday this year.