Negligence Causation Test Revisited: The Difficult Case of Necrotizing Fasciitis

By Kate Hughes

In a recent decision entitled Aristorenas v. Comcare Health Services, [2006] O.J. No. 4039, the Court of Appeal reviewed the applicable legal tests for proving medical malpractice. This case is of particular interest to nurses, midwives, physicians and other health professionals who may be sued in negligence. The case involved a woman who developed necrotizing fasciitis (flesh eating disease) following her caesarian section birth. An obstetrician and a group of nurses, employed by Comcare Health Services, provided home care to the woman following the birth and were found by the Trial Judge to be liable for negligence when her surgical wound became infected. Three days after she was admitted to hospital, the woman was diagnosed with necrotizing fasciitis. She had to undergo life saving surgery, spent ten days in intensive care and then faced a long period of rehabilitation, ultimately missing half a year at work. Given the lack of expert evidence regarding the cause of the still mysterious necrotizing fasciitis, other than it requires the presence of an infection, the Trial Judge that the health care professionals were negligent in their care and that this negligence caused the necrotizing fasciitis. However, on appeal, the Court of Appeal ultimately found that the test for causation had not been made out to satisfactorily establish that the health care practitioners’ actions caused the necrotizing fasciitis.

At trial, it was found that Mrs. Aristorenas, the Plaintiff, entered home care with an obviously infected wound, which then deteriorated. The doctor and the nurses in follow-up care were found negligent in their post-natal treatment of the Plaintiff, who had delivered a baby by caesarian section. The Plaintiff was at a high risk for infection after the caesarian section due to her obesity. She was treated by a physician and several home care nurses over a two week period following the birth. It was found by the Trial Judge that the nurses did not assess the wound appropriately, did not document according to the standards expected (the standards for homecare nurses were found to be the same for other nurses in the profession) and did not notice the serious downward trend. The physician was found to have failed to recognize that the conventional treatment did not assist in healing, despite the large discharges, foul odour and burning pain resulting from the wound. The Comcare nurses had tried to seek the assistance of the Comcare wound expert, however that individual had not been available. Finally, one of the defendant nurses sought the assistance of a senior nurse who, after examining the Plaintiff, immediately advised her to go to the hospital. The Plaintiff was admitted to hospital but it was several days before the hospital staff made the diagnosis of necrotizing fasciitis. The Plaintiff then underwent several surgeries in which an abdomen muscle had to be removed and was replaced with muscle from the Plaintiff’s right leg. The Trial Judge found the homecare nurses and the obstetrician were negligent and assessed damages in the amount of $55,000.

On appeal, the physician and the nurses admitted to negligence with respect to delay in treating the infection. The Appellants did not appeal the Trial Judge’s finding of negligence or his damage award of $55,000.00. The single issue for the Court of Appeal was whether the necrotizing fasciitis suffered by the Plaintiff was caused by the defendants’ negligence.

Cases involving malpractice generally apply a legal test for causation known as the “but for” test, which is as follows:

Causation is established where the Plaintiff proves to the civil standard on a balance of probabilities that the defendant caused or contributed to the injury. The general, but not conclusive, test for causation is the “but for” test, which requires the Plaintiff to show the injury would not have occurred but for the negligence of the defendant.

Courts have recognized that there are cases in which the “but for” test is unworkable; however, they have provided little guidance as to when the “but for” test becomes unworkable. In some cases, the test of “material contribution” as applied, such as in cases dealing with exposure to asbestos. In those cases, where it was clear the Plaintiffs were definitely injured and given there was no other apparent cause or explanation for the injury, a negligent act can be determined to have been caused by the defendants if the Plaintiff “could prove the defendant materially contributed to the injury of the Plaintiff”.

To make matters even more complicated, the Courts also developed the “robust and pragmatic approach” which the Courts said was not a distinct test for causation, but rather an approach to analyse the evidence to demonstrate a necessary causal connection between the conduct and the injury. In these cases, the Court said the legal burden remained with the Plaintiff but that the Court could draw an inference of causation, even though positive or scientific proof for causation has not been adduced. It was this inference that the Trial Judge in Aristorenas relied on in making his decision.

The Trial Judge applied the “robust and pragmatic approach” to the evidence and relied on a chain of inferences. He found that:

1. An infected wound left untreated will develop serious complications;
2. One possible complication, albeit rare, of an infected wound is necrotizing fasciitis;
3. Necrotizing fasciitis developed in the Plaintiff’s infected wound;
4. Whether or not necrotizing fasciitis would have otherwise developed in the Plaintiff is not a matter susceptible of scientific proof;
5. It developed in this case it the very area of the infected wound which was permitted to deteriorate due to the defendant’s lack of care, and was discovered at the proximate time.

In evaluating the evidence, the majority of the Court of Appeal found that it was difficult to establish causation, even if one assumed a link between the delay in the treatment of the infection and contracting necrotizing fasciitis. The Court of Appeal said they had sympathy for the plight of the Plaintiff, who had suffered grievous injuries and had proved serious acts of negligence attributable to the healthcare professionals in providing what should have been basic routine wound care. However, the Court said that, given the current state of the law, the Plaintiff did not make out causation. The Court noted that the necrotizing fasciitis could have entered the wound at a variety of points of time, including at the outset or possibly at the hospital after the negligent delay. It was not sufficient to prove that the adequate diagnosis and treatment would have afforded a chance of avoiding the unfavourable outcome, unless that chance surpasses the threshold of “more likely than not”.

This case is useful to health care providers beyond the specific facts of necrotizing faciitis. This case provides a useful review of the law generally on the legal tests for causation in medical malpractice cases and more specifically guidance as to how the courts will approach difficult cases. The nature of necrotizing fasciitis posed a test case regarding causation as there are no experts and this rare disease still remains a mystery. Despite sympathetic facts and clear harm to the Plaintiff, the court was unwilling to draw the inference to hold the health care providers negligent for the Plaintiff’s acquiring a disease that the evidence indicated was both rare and not necessarily preventable.