Guess what? The steroids aren't making Nick any better and now his kidneys are failing. Good call, Foreman.
While the rest of the Cottages try to figure out what's wrong with Nick, Taub checks out his reflection in a spoon, because convex mirrors are so reliable that way. House tells him to stop, and Taub responds by diagnosing Nick with leukemia, which is stupid since Foreman points out that Nick's white blood cell count is normal. Less spoon-gazing, more file-reading, Taub. House doesn't care about Nick anymore now that he has Taub's attention. He asks him about his racquetball skills. Taub says he's played against Wilson a few times, then suggests diabetes. I've known people with diabetes, and frontal lobe disinhibition never happened to them. Hell, it never happened to Stacey from The Baby-Sitter's Club book series, and she had the worst diabetes ever. Kumar likes a congenital metabolic disorder better, but Taub doesn't think it would rear its ugly head at such a late stage of Nick's life. Kumar points out that Nick's daughter has a neurological condition, which could be related. Yes, they both have a congenital metabolic disorder that shows up in girls at age 7 and men in age 47. Brilliant! House just wants to know how Taub, a Jew, can possibly be able to compete against Wilson, who played tennis for his college team. How quickly we forget that Wilson is supposed to be Jewish, too. I know they only mentioned it in the pilot, but still. I'm pretty sure it counts. Taub says Jews can too be athletic, pointing out Sandy Koufax. House says the Jews always go on about Sandy Koufax. Yes, we do love our Sandy Koufax. Larry King loved him so much that he pretended they were childhood best friends for years. Foreman doesn't like the congenital diagnosis because it involves a lot of testing and he's lazy. Yeah, best to just assume it's neural sarcoidosis and pump the guy up with steroids. House keeps trying to quiz Taub about racquetball, and Taub coolly has an answer to all of his questions and insists that diabetes is a better diagnosis than the congenital thing and requires less work on their part. But House has an idea of how to see if it's a congenital thing: they'll run a peripheral nerve test. But not on Nick, since his brain damage will make the results inaccurate. Instead, they'll do it on Marika. So now we're assuming that it's a congenital condition AND that Marika has the same thing. Kind of a stretch, no? Kumar is assigned to test Marika while Taub gets to do punishment diabetes blood tests until he tells House what he and Wilson are hiding. We cut to Hadley looking confused, both because she doesn't know what's going on and because she's usually the one with the secret stuff going on that Taub and Kumar are clueless about, so this is different for her.