The below is an instructive example of cross-examination questions posed to a pediatric neurology expert witness in a medical malpractice case. An issue in the case is the cause of hypoxic-ischemic encephalopathy (HIE) in a newborn. The pediatric neurology expert witness retained by the defense has opined that the injury to the infant was due to a prenatal infection and thus did not occur during labor and delivery. The pediatric neurologist expert witness is challenged by cross-examination questions through the following cross-examination techniques: medical literature/learned treatises, bias for being a “hired gun,” facts in the medical record that weigh against the opinion, pointing out a potential exaggeration by the expert, and the contradictory opinions of the treating physicians.
Introduction – Cross-Examination of Pediatric Neurology Expert Witness
Q. Good morning, Doctor.
A. Good morning.
Q. I don’t know if you’re aware, there was another witness waiting behind you. So I’d like to move through your cross-examination as quickly as possible. And I wanted to touch on a couple of the subjects that you mentioned during your direct examination. Do you recall stating that this phenomenon that you’ve discussed is well studied and well discussed in the literature? Do you recall stating that?
Q. Okay. Let’s just break down a couple things so we can clarify points for later discussion. Number one, you believe this was an infectious etiology; etiology meaning cause, an infectious cause for this baby’s injury, true?
A. I believe the ultimate cause was infection.
Q. Okay. And we’ll talk about that in a minute.
But now I want to quickly clarify a couple things. You mentioned — you talked a lot about chorioamnionitis increasing the risk of injury to the brain. Do you recall that?
Q. But chorioamnionitis exists in two forms. It exists histologically and it exists clinically, true?
Q. And tell us — well, let’s just — this is cross. Let’s move quickly. Histologically is when you look under a microscope and find some abnormalities.
Q. So that’s histological chorioamnionitis. And there’s clinical chorioamnionitis, which is manifested how? How do you know there’s clinical chorioamnionitis?
A. Typically fever. Others would add other changes in heart rate, the mother, the fetus.
Cross-Examination Questions – Expert Witness Challenged by Absence of Symptom in the Medical Record – Bad Fact
Q. Okay. Fever is the main criteria, okay. So you’re opining that this injury occurred — did you review the records in this case?
Q. So you’re aware that there was no clinical chorioamnionitis until just before birth. True?
A. As defined by the fever, yes.
Q. And we’ve just established that’s how it’s defined, true?
Cross-Examination Questions – Learned Treatise Attack
Q. Let’s use the textbook one. Have you ever read the Williams textbook of obstetrics?
A. I’ve looked at it. I haven’t read it.
Q. Okay. Do you disagree with their definition of clinical chorioamnionitis being once there’s a fever?
A. I assume fever is the primary…
Q. Do you have any reason to disagree with it here today?
A. Only if you’re using the onset of fever to signify the onset of the process. That doesn’t make sense clinically, and I don’t think — well, it just doesn’t make sense. The fever only alerts you to the process. It’s showing some clinical signs. Just as any other illness, if you get pneumonia, you may or may not get a fever. If you don’t get a fever, it takes a while to diagnose. If you get a fever, you diagnose it. But the process may have been going on for two days. It’s no different.
Q. Okay. But the process, if it’s not manifesting a fever, is called histological chorioamnionitis.
Q. Thank you.
So when you opined that this injury occurred two days before birth, there was no fever and so it was a histological chorioamnionitis at that stage, true?
A. That’s the only way you could diagnose it in the absence of fever.
Q. Okay. Can we agree that it didn’t meet the fever criteria to be clinical chorioamnionitis at the time you were opining the injury occurred; therefore, it was a histological chorioamnionitis. True?
A. I don’t really understand that question.
Q. Okay. Well, let’s talk. Can you get this brain injury that you’re talking about with a histological chorioamnionitis?
Q. And is that studied and discussed in the literature?
Q. In fact, you say it’s been known that this type of chorioamnionitis — you’ve seen it many times over your 38 years of practice. Do you recall stating that?
Q. That’s histological chorioamnionitis causing this type of injury over your 38 years of practice?
Q. Doctor, you’re familiar with — what’s the penultimate textbook for pediatric neurology?
A. I don’t use any textbooks anymore. It’s all online. There are a lot of old textbooks.
Q. Did you cite Joseph Volpe in an affidavit that you provided to the Court?
A. Yeah, Volpe has written the same textbook over and over.
Q. It’s in the sixth edition, correct?
A. I think he’s retired. I’m not sure which edition.
Q. Okay. And you cited this in an affidavit you provided to the Court in this very case, didn’t you?
A. In this case?
A. No, I don’t think there’s any —
Q. Not in your report, but in the affidavit you did.
A. You’d have to show me that. I don’t –
Q. Well, is Neurology of the Newborn in the fifth edition which is a pediatric neurology textbook, is this a reasonably reliable authority for the information contained therein?
A. Dr. Volpe’s textbook is reasonable. It’s not always correct, but it’s reasonable.
Q. And does it talk about chorioamnionitis and brain injury?
Q. Okay. Do you agree with this statement: Most term infants who are exposed to chorioamnionitis have an uncomplicated neonatal course and neurological outcome, and histological chorioamnionitis does not appear to increase the risk of adverse outcome?
A. If he said that, I don’t know what references he gives. I’d like to look at it. But that’s —
Example of Lawyer Trying to Impeach Expert Witness with Literature During Cross-Examination Questions
Q. Cite 156, which would be Shalak and Perlman’s article, Chorioamnionitis and Neonatal Encephalopathy in Term Infants With Fetal Academia, Histopathologic Correlations, published in Pediatric Neurology, Volume 33. Are you familiar with the Shalak article?
A. No. I listed many others that show a correlation.
Q. Do you know what an abstract is?
Q. So you can go to PubMed and instead of paying $60 for the article, you can get an abstract for free.
Q. Is the Pediatric Neurology as a source, is that a reasonably reliable journal in this field of pediatric neurology?
A. It’s a reasonable clinical journal.
Q. Okay. Are you familiar with the study by Shalak and Perlman about chorioamnionitis, to look and see if histological chorioamnionitis poses any risk of danger to the infant?
A. I’d be happy to look at it. Off the top of my head — there are many, many articles.
Q. Sir, do you agree that the studies and discussion in the literature suggest that histological chorioamnionitis poses no risk to an infant?
A. I would disagree. And I referenced some of the more recent literature that I rely on that shows there’s an increased risk.
Cross-Examination questions that point out that treating physicians had a different opinion than the pediatric neurology expert witness
Q. Okay. You read the medical records in this case?
Q. This child was seen by pediatric neurology as well as infectious disease, true?
Q. Did any of those clinicians agree with you that infection was the cause of this child’s injuries?
A. I don’t think they defined a specific infection.
Q. Did any of them — well, shall we go look and see what they said? Did you read the N Medical Center records?
Q. I’ll refer to Exhibit 5. You see at the very beginning of this child’s clinical case, they weren’t sure what was wrong with the child. Do you recall that? Do you recall that?
Q. And they recommended — this was the pediatric infectious disease consultation team. Do you recall reading these records?
Q. And one of the things they asked was that the placenta be sent for pathological evaluation looking for funisitis. Do you recall them doing that?
Q. So they’re going through a similar type of process that you’re going through?
Expert Witness Accused of Being a Hired Gun during Cross-Examination Questions
Q. Except they’re not being paid for litigation purposes, they’re taking care of the child, true?
A. Yes, I’m being paid.
Cross-Examination Questions – Expert Witness Opinion Contrasted With That of Treating Doctor
Q. So the unpaid pathologist, who we — you don’t know; I don’t know him either — he found no — nothing here that would explain damage to an infant, true?
A. No, I don’t think that’s correct. The definition of chorioamnionitis is here. That’s what’s required to initiate this immune response. There may be more detailed changes that a placental pathologist could find, but I think Dr. D diagnosed chorioamnionitis, which is what I need to support an infectious process that could trigger an immune response. There may be more details with a more experienced examiner, but we do have chorioamnionitis here. It’s clear. That was his diagnosis.
Additional Cross-Examination Questions Attacking the Pediatric Neurology Expert Witness Based on Literature
Q. And across the world, the Royal College of Obstetricians and Gynecologists in London?
A. I find it’s helpful. Again, some of the information in there is based on old studies. You’re asking me about the ultrasound in the first day or two of life. We have neuroradiology conferences every week. There’s frequently a heated argument over the size of the ventricles, these gray echoes, even among the neuroradiologists. That’s all I can say is, that I watch my colleagues debate these issues. The ultrasound is very good in the premature babies. That’s where we use it mainly. It’s very good for looking for blood, for hydrocephalus. But outside of that, there are endless debates about its usefulness and its interpretation. And many times I’ve been shown what is supposedly abnormal and — again, maybe it’s my vision, I can’t see it, it’s so subtle. So I do rely on the radiologists to make a decision on these things. But in this case, whether there are subtle changes or not, it doesn’t really affect my opinion.
Q. But the panel of experts who drafted this document — you understand that they said it’s incredibly important in timing because if an injury is two days old, it should be there on that first scan according to these experts. True?
A. Well, the neurology community has practice parameters. Child Neurology Society has a practice parameter on the use of imaging in the newborn. And one of the consensus opinions of the neurological experts was that timing of injuries with any of these modalities, ultrasounds, CT, MRI, is inherently unreliable, there’s such a wide window of variability. So from a neurological perspective — and this is published by neurology — it’s readily available — using any of these modalities to time the onset is, at best, difficult and usually not reliable.
Q. So you disagree with this panel of experts when they say that the CT scan can tell you if there’s been an injury two days ago or not?
A. I think most of the authors are pediatricians and obstetricians.
Q. You disagree with them?
A. I would disagree.
Q. You also stated on direct — and I wrote down, that excessive contractions have never been linked to injury in the child. Do you recall stating that?
Q. Okay. But again, these experts have an entire chapter on intrapartum considerations and assessments.
A. And what?
Q. And assessments.
Q. Do they directly address that issue?
A. I haven’t read this in years, so I wouldn’t — you’d have to show me the —
Fodder for Cross-Examination Questions – Potential Exaggeration Pointed Out
Q. You stated the Apgar scores were good. Do you recall stating that?
Q. The first Apgar score, what was S’s condition with that first Apgar score?
A. It was 2.
Q. Two meaning she had a heartbeat. Otherwise, she was…
A. Yeah, the presence of a heartbeat — well, the one-minute Apgar is never correlated with any neurological issue. It just alerts the obstetrician that you may need to resuscitate the baby.
It’s really the five, ten, 15, and 20-minute Apgars that have any correlation with brain damage.
Q. Does this book also provide timing of the injury apart from neuroimaging by looking at the fetal heart rate tracing which I think you stated was unreliable?
A. From my standpoint as a neurologist, and I think this is a well-referenced — and I had references in my letter – electronic fetal heart rate monitoring has never been shown to predict brain damage. And the reliability of even the same examiner giving the same opinion over time is so unreliable that I don’t find it’s helpful at all in evaluating these cases.
Q. So you would disagree then with this panel of experts who stated that a patient who comes in with a Category I fetal heart rate pattern that converts to a Category III, as defined by the Eunice Kennedy Shriver National Institute of Child Health and Human Development Guidelines, is predictive of intrapartum timing of a hypoxic ischemic event?
Q. You disagree with that?
A. I think the literature I’m familiar with and my own experiences, a false positive rate is 99 percent. No test that has a false positive rate of 99 percent — well, nowadays that test would not be allowed — it’s totally unreliable.
Counsel Points Out During Cross-Examination Questions Other Cases Pediatric Neurology Expert Witness Has Worked On
Q. Doctor, you and I have met one time prior. Do you recall that?
Q. You testified in a case where Miss L was a mother who gave birth to a child who had a neurological insult?
A. Was that the D —
A. D case? I think that was a deposition, yeah.
Q. And you opined that the injuries were caused because the mother had a thrombophilia. Do you recall that?
A. Vaguely, yes.
Q. The mother was subsequently tested for the thrombophilia that you opined she had.
A. I don’t remember the details.
Q. Were you aware of that?
A. I don’t remember the details.
Q. I want to clarify one point. The phenomenon that you’re referring to as fetal inflammatory response syndrome?
Q. You saw the pathology report from the Medical Center — the N Medical Center, correct?
Q. And the chorioamnionitis was on the maternal side. Do you recall that?
A. I think in the report from the pathologist at N Medical Center, yes.
Q. Okay. So tell me whose response is causing the injury through your theory?
A. Well, ultimately it’s the mother’s triggering of the immune response which affects the infant. The cytokine response can directly affect the infant’s brain. That, in itself — unless you had an autopsy where you had the brain available, you know, you may or may not see something on the fetal side. That would take a more sophisticated exam, such as a placental pathologist could do.
But I think here we have, at least by the first report by their pathologist, the maternal side is affected. That’s why I think we need to hear from the placental pathologist if they see something on the fetal side. And then ultimately, we have a brain lesion that’s totally consistent with the chorioamnionitis being the precipitating cause. So I don’t know the qualifications or the depth of the exam done by the N Medical Center pathologist, so I would defer some of this to the placental pathologist.
Q. Okay. I don’t think you heard my question. I’ll have it read back.
COURT REPORTER: So tell me whose response is causing the injury through your theory.
A. Well, there are two actors here. Obviously the maternal side initiates the response. And then it’s the fetal-maternal interaction that responds to the cytokines that may be present in the mother. These have been measured in the mother — humans, not animal studies. Interleukin 6, all these cytokines, I won’t name them all, it’s not that important. But those same antibodies can then pass through the placenta, the blood-brain barrier of the baby and have been demonstrated in animals but in human tissue. So the main factor is the mother initiates the process. Once it begins, you may or may not see something on the fetal side of the placenta. But the key point is the cytokines can penetrate the blood-brain barrier of the baby and may cause damage.
So the fact that you have infection in the maternal side is the key point here, if that’s what you’re asking.
Q. Well, let’s break this down because it is important.
So it’s your hypothesis that the mother’s immune response is generated when it encounters a pathogen, and it releases cytokines, one of which is interleukin 6 you stated?
Q. And those cross the placenta. Is this your opinion?
Q. And somehow they go up and injure the child’s brain. Is that what you’re stating?
Cross-Examination Questions – Attacking with Contrary Facts – Blood Cultures were all negative
Q. Staph aureus, streptococcus, what was causing all these problems, sir?
A. We don’t know that.
Q. What do you mean?
A. The blood culture that was obtained was negative.
Q. Well, they tested the baby’s mucous membranes. What did they find on that culture?
A. I assume they were looking for herpes, and they didn’t find that.
Q. Were they also looking for MRSA and a bunch of pathogens in the — did you read the records, sir?
Q. Did they look for anything to grow?
A. It would be mainly bacterial contaminants. They didn’t really test for — well, for viral or fungi.
Q. Did they find anything?
A. With the testing they did, no.
Q. How about the urine? They tested the urine, too, didn’t they?
Q. Did they find anything growing in the urine?
A. No, I don’t think so.
Q. Okay. So everything, every search for any infection, came back negative in the child. True?
Kelly J. Wilbur, Esq., is Assistant Vice President/Associate Consultant for SEAK, Inc. The Expert Witness Training Company. She was an insurance defense and commercial litigator for five years prior to joining SEAK. Kelly can be reached at Kelly@seak.com or 617-791-6802.
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