Opinion ID: 1772923
Heading Depth: 1
Heading Rank: 3

Heading: Defendants' Rebuttal Evidence

Text: The evidence introduced by the defendants consisted of testimony by Drs. Stephen Youngberg, and Jarrell Myrick, and a stipulation as to the testimony of Dr. Sheldon Kottle. It is upon this evidence which the defendants must rely to overcome the presumption and to prove by a preponderance of the evidence that the work injury did not to any extent aggravate, accelerate or in any way combine with the preexisting disease to produce Walton's disability. Dr. Youngberg testified that he was a subspecialist in internal medicine, specializing in diseases of the kidney, with seven years experience in the subspecialty of nephrology. He first saw Walton on July 14, 1981, approximately eleven weeks after his accident. Dr. Youngberg did not take a written history from the patient, and the one taken for him by a medical resident did not mention the accident. Apparently, Dr. Youngberg did not consider whether Walton's twenty foot fall could have been a factor in accelerating or aggravating his kidney disorder until this litigation arose. Prior to giving his testimony, Dr. Youngberg had been discharged by Walton and replaced with another physician. When Dr. Youngberg was asked to express an opinion as to the existence of a causal relationship, he testified that the data available to him did not contain any evidence that the accident accelerated or aggravated the kidney disease. This information consisted primarily of the three measurements of Walton's creatinine content performed by other doctors and laboratories. Dr. Youngberg was of the opinion that these three measurements, i.e., 2.3 in September, 1980, 2.9 in January, 1981, and 4.1 a week after the April 23, 1981 accident, reflected only a normal progression of Walton's diabetic renal disease. He explained that the disease's rate of progression usually is reflected by a logarithmic or hyperbolic function, not a linear function. Dr. Youngberg conceded that when Walton's three measurements were entered on a graph, they described a line which appeared to change precipitously near the time of the accident. Nonetheless, he testified, when this data is normalized, by showing the reciprocals of these entries, the curved line would be changed into a straight line consistent with a normal progression of the kidney disease. However, the medical treatises which Dr. Youngberg testified explain this phenomenon were not introduced into evidence, and he did not make plain or understandable why the mathematical procedure of normalization must be accepted as an accurate reflection of the actual progression of Walton's renal failure. Dr. Youngberg conceded that creatinine measurements are considered to have a limited accuracy of plus or minus 4/10ths of a milligram between the creatinine levels of 0.5 and 2.0. Above the creatinine level of 2.0, he said, the margin of error is even greater because the serum must be diluted out in performing the test. Furthermore, he testified, the actual readings may differ slightly according to variations between individual laboratories. On cross examination, Dr. Youngberg's attention was directed to a fourth creatinine measurement, not included in his graph data, performed on June 4, 1981, which showed a level of 3.9. He was asked if this reading, following the preceding measurements of 2.3, 2.9 and 4.1, showed a recession of Walton's creatinine following its elevation near the time of the accident, indicating a traumatic acceleration of the kidney disorder. Dr. Youngberg conceded that he had not previously incorporated the 3.9 measurement in his analysis but maintained that with its insertion Walton's readings would still reflect the general trend of normal progress in his kidney disorder. He also suggested that, because of the margin of inaccuracy and variable nature of creatinine test readings, a measurement of 3.9 is practically the same as one of 4.1. Dr. Jarrell Myrick, an assistant professor in medicine at LSU Medical School in Shreveport and a practitioner in nephrology since 1979, formerly had practiced with Drs. Youngberg and Kottle but not during the time Walton was their patient. He did not examine or treat Walton. In his testimony, Dr. Myrick agreed with all of Dr. Youngberg's conclusions but added no new evidence or reasoning in support of them. The parties stipulated that Dr. Sheldon Kottle, a nephrologist practicing with Dr. Youngberg, if called, would have testified the same as Dr. Youngberg.