There are subjects we just can’t touch on this blog.

First, politics: We’d annoy each other, along with half our readers.

Second, religion: Ditto.

Third, when treating physicians must be disclosed as expert witnesses or can give expert testimony at trial: If we ever touched on that subject, we wouldn’t just annoy each other; we’d trap ourselves.

Depending on the circumstances of a particular case, sometimes we want treating physicians to be permitted to testify broadly (without having provided expert reports), and sometimes we want their testimony to be more confined (or restricted to the contents of reports).

So we’re offering today, without commentary, a recent decision on that subject.

In re Aredia and Zometa Prods. Liab. Litig., No. 3:08-0068, 2009 WL 2496833 (M.D. Tenn. Aug. 13, 2009), tells us nothing about the particular case. We’ll guess that the plaintiff, Mrs. Fussman, ingested Aredia (or maybe Zometa) and allegedly suffered an injury. The “defendant” — we’ll guess that it’s Novartis — moved under Daubert to exclude testimony offered by Mrs. Fussman’s treating physicians about the cause of her injury. The court ultimately held that Mrs. Fussman’s retained expert provided the testimony needed for purposes of summary judgment, so the motion to exclude the treaters’ testimony was moot.

(We oughta just stop typing here, leaving you to wonder why the heck we chose to publish a post about that result.)

Before deciding that the issue was moot, the trial court collected and discussed applicable precedent dealing with the permissible scope of a treating physician’s testimony when the treater has not been retained as an expert. (We must say, though, that the opinion reads a bit like one of those Am. Jur. chapters that says, “The law is ‘black.’ [Footnote.] The law is ‘white.’ [Footnote.]” and makes no effort to rationalize the conflicting statements.)

The court noted that a treating physician can generally “provide expert testimony regarding a patient’s illness, the appropriate diagnosis for that illness, and the cause of the illness.” Id. at *1. But that testimony is subject to the Daubert requirements that any opinion must be reasonably based in the expert’s knowledge of his or her discipline. Id. When the doctor strays from his or her discipline, the testimony should be excluded.

Thus, a physician can diagnose and treat exposure to pesticides, but cannot testify to the exact chemical to which the plaintiff was exposed. Id. On the other hand, “determining causation may . . . be an integral part of ‘treating’ a patient.” Id. at *2. If it is, then the physician can testify to an opinion he formed on that subject in the course of treating the patient (as opposed to an opinion developed after the fact, for purposes of litigation).

“[W]hen the nature and scope of the treating physician’s testimony strays from the core of the physician’s treatment, Rule 26 requires the filing of an expert report from the physician.” Id. “A treating physician for whom no expert report is supplied is not permitted to go beyond the information acquired or the opinion reached as a result of the treating relationship to opine as to the causation of an injury or give an opinion regarding the view of an expert called by the defendant.” Id.

“When the doctor’s opinion testimony extends beyond the facts disclosed during care and treatment of the patient and the doctor is specially retained to develop opinion testimony, he or she is subject to the provisions of Rule 26(a)(2)(B).” Id. at *3.

Got that?

We should stick to politics and religion.

(On that score, Bexis says Herrmann is a heathen and a libertarian; Herrmann says Bexis uses words that are too big.)