OK, I've got a stumper here (and I don't stump easily). The patient is a toddler between 18 and 24 months who has been healthy other than some eczema. About a week and a half ago, the family noticed a fishy odor emanating from her entire body, better after bathing, progressively worse through the day until she gets bathed again. It's worse if she gets sweaty. It's bad enough that her siblings have been refusing to sleep in the same room with her and friends and neighbors have been noticing it, even outdoors, when the child is near. She has been eating more than usual, although her growth chart looks fine. No polyuria. She's in diapers and the diapers do smell fishy, but it's unclear whether that's the urine or the diaper itself.
In the room, she looks fantastic. Running around, happy, playful. Some scratches on her ankles from the eczema, but otherwise nothing amiss. Except... there is quite an odor in the room and they say they bathed her just before coming to the office.
Mom Googled and found about trimethylaminuria (TMAU). But if it's that, why did it start ten days ago? I'm reading that some weird skin bacterial overgrowth can do it, but what and why? And they didn't suddenly take on a seafood diet. No new bath products. No obvious environmental changes.
I'm sending an CMP and an ammonia level (it was all I could think of). I'm also doing a Genetics referral because I can't test for TMAU, but although TMAU can present acutely, that would be an unusual presentation of an unusual disease.
Anyone have any useful thoughts?
-PGY-22
UPDATE: Serum ammonia is normal.