Aftera fabulous week, another pericardial effusion. And they still don't know what's wrong. This is so scary, and so frustrating. And so expensive!

Once again, Bao's pericardial sac had to be "tapped". But this is not a disease. It's a symptom. The question is, A symptom of what?

I have a theory. After the hernia surgery, Bao was on a 7-day course of antibiotics. After two days, he was a different dog. Lively, prancing, playing, happy. A few days after we stopped the antibiotics, he slowed down a little. A few more days, and he had another pericardial effusion.

So here's my theory. He has a sub-clinical infection somewhere; a handful of bacteria on a mission, but not enough to show up on standard blood tests. Although the post-surgery antibiotics were prophylactic (to help stop infection) they nonetheless zapped these under-the-radar bacteria -- but didn't kill them all off. And when we stopped the antibiotics, the bacteria regrouped.

Tomorrow, we'll go see Dr Mike and I'm going to suggest that Bao goes back on antibiotics for a week or two, just to see what happens. They can't hurt him. And if he suddenly peps up again, at least it's a data point.

This is a complete puzzle, the the veterinarians and to me. Any ideas?

The only good thing about the situation is that Bao is comfortable, happy, and not in any kind of pain. And that's a lot to be thankful for.