The Disturbing Case of the Shrinking Thymus

Last Friday I was listening to RadioLab on MPR and caught just a part of one story that went like this. (I confess I was working on something else, and so missed some of it, such as where and when this debacle occurred.)

At some point in the later 19th century, Sudden Infant Death Syndrome was identified as a problem (although it was called by different names). When doctors autopsied babies who had died from SIDS, they found that their thymus glands were larger than average. So, thinking that the thymus was obstructing the airway and causing the child's death, they figured out a way to shrink the thymuses of any living children they identified who had an enlarged one. Doing so would prevent the child from dying of SIDS, they believed. And what was the method they came up with for shrinking the thymus? Direct radiation in pretty high doses.

I didn't hear how much this "treatment" was carried out, but from looking around on the web it looks like it went on between 1900 and 1950. Of course, we now know that the children who got their thymuses irradiated were much more likely to develop cancer twenty or thirty years later. (Here's an article about pediatric radiology that covers the topic from a scholarly perspective.)

But if that was the whole story, I wouldn't be writing about it. Believe it or not, it actually gets worse.

Get this... back in the 19th century when medical students first were able to dissect cadavers as part of their studies, the bodies they acquired (at first illegally, as described so well in the novel The Dress Lodger) were predominantly those of poor people -- in fact, at some point around mid-century the bodies of people who died paupers were turned over by law to medical schools. Based on many autopsies over the years, the average size of the thymus was determined and recorded for use in physiology classes.

But what no one realized for a hundred years or so was that the thymus gland's size is affected by stress, and that these poor, beaten down people who ended up as paupers whose bodies were indentured to science had abnormally small thymuses.

So when the SIDS babies were autopsied, their thymus glands seemed as though they were enlarged -- but they were actually normal, healthy thymuses.

And so the radiation treatment was doubly misbegotten -- it caused later harm, and had no chance of doing any present good.

AAAAAggggggghhhh!

(Footnote: I confess I'm pretty sure it was RadioLab where I heard this, but I can't seem to find any mention of it on their website. I think this is because they have not yet posted their recent shows, but since they don't list dates with their archives, I'm not entirely sure.)

UPDATE: RadioLab has indeed posted the show now (the segment in question can be found about three-quarters of the way through the show). Thanks to Syndicate and Hague for the link to the show.

FINAL UPDATE: I just listened to the RadioLab broadcast again from the link above, and realized that what I had remembered as the thyroid gland was actually the thymus gland. Many apologies for my layperson stupidity; that's what I get for doing something from memory while trying to work at the same time. I've corrected all instances of the gland's name in this text.