should have done so. In our opinion, however, if the jury believed the testimony offered by plaintiff it could properly have found that even upon defendant’s first examination he should have recognized that plaintiff was so far retarded in her development that he should have undertaken a further investigation to determine the cause, including laboratory tests, and that if he had done so he should have made a diagnosis of hypothyroidism within a relatively short period of time.
Plaintiff also offered testimony that if such cases are treated within three months, "the odds are probably seven out of eight that she would have an IQ of about 85 or 90” (within the normal range); that if plaintiff had been treated between six and 14 months, there is a 65 or 70 percent chance that her IQ would have been above 75; and that if treated beyond 14 or 15 months, she "is almost surely going to have some reduced IQ, probably below 70.” Plaintiff, at age 6 had an IQ of 41.
We believe that if the jury believed this evidence, as it was entitled to do, it could have properly found that defendant, who first examined plaintiff when she was 10 months old, should have made the diagnosis of hypothyroidism well within the six to 14-month period, during which it was reasonably probable that the prompt undertaking of treatment would have resulted in her having an IQ of 75 or better and that, as a matter of reasonable probability, defendant’s failure to make a reasonably prompt diagnosis resulted in at least some substantial impairment of her mental development.
Defendant cites Wintersteen v. Semler, 197 Or 601, 636, 250 P2d 420, 255 P2d 138 (1953), for the proposition that in such cases it must be established with "reasonable certainty that the damages sought resulted from the act complained of.”
In cases involving personal injuries, however, it is the rule that in order to establish the necessary causal