Hmmm...either no one out there cares much about this quirk of Matthew's, or no one knows quite what to say about it. Well, at work last night I googled 'children holding breath' and I got quite a response. There were two scholarly articles, one of which quoted several research studies and was published in a medical journal, so that one I trusted the most. Surprisingly, 27 % of children have what are called "Simple Breath Holding Spells" (I thought that number higher than I expected), where emotional upset or pain causes a breath holding spell that does not result in fainting or falling. 4.6% of children have what are called "Severe Breath Holding Spells" (or BHS) where they will hold their breath until they lose consciousness, and sometimes they twitch almost like a seizure but not quite (Matthew does this). There are two types of severe BHS, which can look similar to seizure disorders or to some rare cardiovascular disorders. Matthew actually fits the profile for both types, which are cyanotic BHS and pallid BHS. A small percentage of children actually do have both types. Cyanotic BHS is usually caused by an emotional upset, and the child usually has its first episode between ages 6 and 12 months. The child starts to cry, exhaling and exhaling until they turn blue, and then faint. Classic Matthew. Pallid BHS is usually caused by pain, especially to the head, and the child starts to cry, stops breathing, turns very pale, and faints. Classic Matthew. In both cases it is theorized to be linked to Vagus Nerve stimulation, which is what causes 'fainting at the sight of blood' or 'with shocking news,' etc.
So! Good news thus far on the internet hunt for answers...I have yet to come accross a forum where parents swap stories or support each other, but hopefully I'll find one soon. Even ONE other parent for me to talk to about it would be helpful! Oh, and, while linked occasionally with other, more serious heart or other conditions, Matthew has none of the symptoms associated with these more serious conditions, and BHS is usually harmless.
Interestingly, 17% of kids with pallid BHS are prone to fainting as adults...not BHS, but fainting for other reasons. By the age of 7 or 8 virtually all kids with BHS stop, thus 'growing out of it.'
Also, iron deficiency has been linked with some cases and treatment (iron supplements) improves the condition for those children.
You never know when you may need this info. Plus, I thought you may be interested. I'll still bring him to our doctor, but it's reassuring to know we're not alone.