Defense Questions Infectious Disease Expert’s Differential Diagnosis Methodology

Court: United States District Court for the Eastern District of PennsylvaniaJurisdiction: FederalCase Name: Terry v. McNEIL-PPC, Inc. (In re: Tylenol (Acetaminophen) Mktg., Sales Practices, & Prods. Liab. Litig.)Citation: 2016 U.S. Dist. LEXIS 98862

The defendants argued the plaintiff’s infectious disease expert was unqualified and employed unreliable methodology.

Facts

This product liability case was part of the Tylenol marketing multidistrict litigation (MDL). The lawsuit focused on allegations of liver damage caused by paracetamol use at or just above the recommended dosage. Paracetamol, also known as acetaminophen, is used to treat mild to moderate pain. The first bellwether was set for trial. The complainant alleged that the plaintiff’s sister died of acute liver failure after taking Extra Strength Tylenol. Furthermore, the complaint claimed the defendants, the makers and producers of Extra Strength Tylenol, were liable on several fronts. The plaintiff hired an infectious disease expert to testify as to the cause of her sister’s death.

The Plaintiff’s Infectious Disease Expert

The infectious disease expert witness was board-certified in both internal medicine and infectious diseases. He previously served as Director of Inpatient Pediatrics at a medical center. Moreover, the expert served as Medical Director at two different hospitals. At one of them, he was the Medical Director of Infectious Diseases. The expert witness was also the Deputy Chief of Medicine at another medical center. He also worked as a professor of medicine and as a supervised consultant physician. He received education and training in acetaminophen toxicity.

The infectious disease expert witness used the differential diagnosis to determine the cause of death of the deceased. He checked the patient’s medical history and laboratory reports to determine the cause of her illness.

Discussion

The defendants argued that the infectious disease expert was not an expert in acute liver failure. Thus, the defendants claimed the expert witness was not qualified to testify as an expert in this case. The court noted the expert diagnosed approximately 20 people with acute acetaminophen-induced liver failure in his 40 years as a surgeon. The court further noted that the expert was conscious of the effects of acute liver failure caused by acetaminophen and how to treat it with an antidote. Additionally, the court observed the expert had written adverse event records for the FDA and poison control centers during his career. While on several pharmaceutical boards in various hospitals, the expert tracked the side effects of the hospital’s drug delivery, including those of acetaminophen. The court, therefore, found him suitably qualified to offer an opinion.

The defendants also argued that the expert’s methodology was unreliable. They claimed he could not offer an opinion of the dose the deceased took which caused her acute liver failure. The court noted that differential diagnosis was a practice used by physicians to eliminate factors in determining causation. In addition, physicians used differential diagnosis to diagnose a patient’s symptoms. The court failed to see how the expert’s inability to answer a specific question affected his ability to opine on causation based on differential diagnosis.

Ruling

The motion to exclude the testimony of the infectious disease expert witness was denied.

Key Takeaways for Experts

This case illustrates the importance of an expert’s career experience. In this case, the defendants claimed the infectious disease expert was unqualified to testify about acute liver failure because he was not an expert in this specialty. However, the expert had experience diagnosing patients with acetaminophen-induced liver failure. It’s important medical experts have the experience to support their opinion, especially when it comes to the cause of death.