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Case Note – Pederson v Northern NSW Local Health District [2020] NSWSC 741

  • Legal Development 3 July 2020 3 July 2020
  • Asia Pacific

Case Note – Pederson v Northern NSW Local Health District [2020] NSWSC 741

Medical malpractice, causation, epidemiology probabilities, compelling medical examinations

The defendant, Northern New South Wales Local Health District, applied for an order compelling the medical examination of the plaintiff, Luke Pederson, by way of taking  saliva samples for the purpose of genetic analysis.  This interlocutory decision concerned the question of whether, in the exercise of the court's discretion, orders compelling the examination should be made in the circumstances of the case.

The plaintiff was a 10 year old boy who sued the hospital for injuries that he suffered during his birth on 14 December 2009.  As a result of delays caused by the alleged negligence of the hospital, the plaintiff suffered Hypoxia Ischemia Encephalopathy (HIE) which resulted in serious disabilities.  The most significant of the disabilities was the alleged development of Autistic Syndrome Disorder (ASD) which was diagnosed when the plaintiff was 6 years old.   The plaintiff was claiming significant damages in respect of the ASD.  However, the issue of whether the ASD was caused by the defendant's alleged negligence was in dispute.  The defendant had admitted that it breached its duty of care in respect of failing to ensure an obstetrician was present at delivery and failing to manage complications during the delivery in a timely manner. The defendant accepted that the plaintiff suffered ASD, but it denied the alleged  connection of ASD to the delays in delivery.  

Both parties had filed expert evidence on the issue of causation. The plaintiff's independent expert and his treating specialist expressed the opinion that the plaintiff's ASD was a direct result of the HIE.  Both experts relied on studies that showed an increased risk of ASD in infants born with impaired gas exchange. The defendant's expert, who was a geneticist, stated that there were many causes of ASD and an underlying diagnosis could be made in about 25% of affected individuals with causes including chromosomal abnormalities and single gene disorders. The expert suggested that it was possible to do genetic testing to obtain a definitive diagnosis, however  a negative test result did not exclude a genetic cause for ASD since the cause may be in one of the genes examined but not detected for technical reasons, or in a gene that was not examined as that gene had not yet been discovered as a cause of genetic disorder.

The plaintiff's tutor objected to the testing on a number of grounds including that it would cause distress and anxiety to the plaintiff, and it was uncertain as to whether the test would be able to demonstrate anything probative about the plaintiff's case.  Justice Campbell noted that the aetiology of ASD was uncertain.  Both parties had relied on epidemiological studies to support their respective theories of the case.  The plaintiff relied on studies to argue that children who suffer HIE are 5.9 times more likely to have been diagnosed with ASD compared to infants who did not experience HIE.  The defendant relied upon the epidemiological studies to argue that a percentage of the cases where an underlying cause can be identified for ASD are associated with genetic predisposition. Justice Campbell noted that each case theory was based on epidemiology and  referred to the judgment of Spiegelman CJ in Seltsam & McGuiness [2000] 49 NSWLR 262.  In that case the Chief Justice expounded the principles governing the proper use of epidemiological evidence as a means of discharging the civil onus of proof when the cause of the condition is uncertain in medical science.  His Honour stated:

"Epidemiology is, as I have noted above, concerned only with the study of disease in human populations.  It is not, of itself, directed to the circumstances of an individual case.  For the purpose of determining whether exposure to a particular substance is the legal cause of a particular disease, epidemiology only provides evidence of possibility."

Justice Campbell noted that there were some cases  in which medical science could not identify the biological or pathological mechanisms by which a disease or condition developed and there were also cases where medical science could not determine the existence of a causal relationship between a disease or condition and a particular act or omission. However, that  was not necessarily determinative of the existence or non existence of a causal relationship for the purposes of attributing legal responsibility. In such cases epidemiological evidence could be used to fill the gap.  It was of particular potential utility in the field of toxic torts especially in the case of diseases with long latency periods.  In circumstances where the aetiology of a disease was uncertain, or subject to significant scientific dispute, the courts are not disenabled from making decisions as to causation on the balance of probability. In the case at hand, medical science was prepared to say that it is possible that there is a connection between the plaintiff's birth injury and his ASD. Equally, medical science said it is possible that ASD had a genetic cause.  Whether one or both matters were in fact causes would  depend upon a decision of fact on the balance of probabilities involving an inferential reasoning process in which all of the evidence, expert and lay, would be taken into account.

Justice Campbell held that whilst medical science might require something approaching certainty before a scientific deduction could be made, the civil courts did not operate that way. The courts could draw an inference as to probability from a number of pieces of evidence, each piece of which in itself did not rise above the level of possibility. Epidemiological studies and expert opinions based on such studies were able to form "strands in a cable" of a circumstantial case. The defendant was therefore permitted to perform the genetic testing on the plaintiff even if it was not going to lead to a certain result.

This decision is an important reminder to insurers defending medical liability cases that the opinions of medical experts based only on possibility, may form evidence that the courts will take into account, in conjunction with other evidence, when making causation findings on the balance of probabilities. The decision also highlights some factors a court must consider when a plaintiff resists making themselves available for a medical examination. 

As to compelling plaintiffs to attend medical examinations, the decision can be contrasted with the recent decision of Judicial Registrar Clayton in Victoria in Thomson v Transport Accident Commission [2020] VSC 310. In that case the Registrar declined to compel the plaintiff to attend a further psychiatric examination required by the defendant pursuant to Rule 33.04 of the Supreme Court (General Civil Procedure Rules 2015). In the proceeding the plaintiff had been examined by a psychiatric jointly appointed by the parties by agreement under certain case management protocols and subsequently examined by another psychiatrist for the defendant. The examination arranged was with a new and third psychiatrist.

The legal authorities to which the decision referred indicate that a court has a discretion to compel a plaintiff to attend. The reasonableness of the request to attend and the reasonableness of the plaintiff's objection must be "balanced to obtain a just determination". Factors such as the need for the examination, the prejudice to a defendant if an examination was not permitted, the stress, inconvenience and discomfort to a plaintiff and the existing medical opinions available can all be considered. In psychiatric claims, a plaintiff's mental health can be considered.

Registrar Clayton exercised her discretion and balancing all the relevant factors identified in her judgment ruled the plaintiff need not attend the examination with the new psychiatrist, as the defendant could pose additional questions to an earlier psychiatrist and obtain a supplementary report. She found therefore the defendant's request was unreasonable, despite the fact the plaintiff had failed to adduce sufficient evidence to satisfy her that she had reasonable grounds for refusing.

We note the defendant was not entirely shut out of arranging future examinations and a court could compel the plaintiff to attend, if it was considered justified on the material.

We observe that in complex injury claims most parties endeavour to strike a balance between investigating the central medical issues in a case and the cost and inconvenience of doing so. A court will, by Rule 33.04 discourage "doctor shopping" or attempts to obtain more favourable medical opinions, but where there is a real medical issue that has not been explored previously by an examining doctor or new material comes to light that requires further consideration, the justification for additional examinations will be more compelling. The need to identify these issues with some precision and in a timely manner will be important when managing claims.

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