Cone Rod Dystrophies, or a rare epic failure of MeSH

If you search Cone Rod Dystrophy in MeSH, you'll find that it is an entry term for Retinitis Pigmentosa, and (at least in the PubMed Mesh database), it maps only to that one term. I stupidly assumed that this meant it was the same thing. (Bad librarian, no cookie!)

My search was: "Retinitis Pigmentosa/therapy"[Majr]

Luckily, one of the articles on the topic set me straight. The abstract clearly stated that cone rod dystrophy was different from retinitis pigmentosa. I immediately stopped collecting articles on RP, and investigated.

It turns out that some people consider cone rod dystrophy to be a sub-type of retinitis pigmentosa. The more prevalent form of RP is rod cone dystrophy, where the rods are affected before the cones, resulting in night blindness. In Cone Rod Dystrophy, the cones are affected before the rods, resulting in a loss of central vision and sometimes in colour blindness. The causes of Cone Rod Dystrophy are mostly genetic, unlike with standard RP.

Armed with this new data, my new search was: ("cone rod dystrophy"[all fields] OR "cone rod dystrophies"[all fields] OR "cone rod degeneration"[all fields]) AND "Retinitis Pigmentosa/therapy"[Mesh]

However, I noticed that combining with the RP term reduced the number of articles to less than half of the results found with the keywords. It seemed odd - surely if CRD was a subtype of RP, most of the articles should have been included?

Experimental search: ("cone rod dystrophy"[all fields] OR "cone rod dystrophies"[all fields] OR "cone rod degeneration"[all fields]) NOT "Retinitis Pigmentosa/therapy"[Mesh]

Whoo-ey! It turns out that many articles about Cone Rod Dystrophy are indexed under "Retinal Diseases"[Mesh], or even more obscure terms. I noticed that the MeSH "Retinal Dystrophies" was hardly used at all, when I would have guessed that it would be the closest MeSH to Cone Rod Dystrophies. It's strange, because Cone Rod Dystrophies is so clearly an entry term for Retinitis Pigmentosa, and yet the indexers do not seem to be treating it as such.

It turned out that the best search was: "cone rod dystrophy"[all fields] OR "cone rod dystrophies"[all fields] OR "cone rod degeneration"[all fields]

I ended up going through all of the results, which was good because there was very little on therapy, and fortunately a couple of articles mentioned that fact (but of course it wasn't reflected in the indexing since the article wasn't about that). But that's a problem that had nothing to do with the indexing.

Normally MeSH terms are truly awesome, and too often taken for granted by those lucky enough to work in health librarianship. We only remember how brilliant they are when we end up searching some other subject and see how inaccurate and inconsistent the use of controlled vocabulary can truly be. However, sometimes there is a term within our own literature that shows us how messy things can be if indexing is not up to Medline's usual high standards.

Home birth

I searched home birth in the MeSH database and got no results.

I searched home birth in PubMed Reminer and found Home Childbirth.

MeSH database, can I get an "oops"?

D'as right.