When I explain causation to potential clients, I talk about the bad outcome they’re here to discuss (i.e. a misdiagnosed stroke, an untreated infection, etc.) and why they think the healthcare provider was negligent. I then tell them that we need to prove a causal link between the negligence and the harm, or in other words to think about what actually happened, and then consider what likely would have happened without the negligence.
This analysis seems simple, but in practice it can be anything but. One unique issue we see in medical negligence cases is that sometimes there is only limited direct evidence to prove causation, but if the standard of care was met, there would have been better evidence. For example, if imaging is necessary to determine a patient’s status during a critical time period to figure out if the proper treatment would have made a difference, but the imaging wasn’t done because of the treatment provider’s negligence.
This was the case in Hasan v Trillium Health Centre, where the defendant physician breached the standard of care by failing to diagnose a stroke on December 3 and 4, 2011. Had the stroke been considered as a possible diagnosis, special internal imaging called a CT Angiogram (CTA) would have been ordered which would have diagnosed the stroke and shown its progression. Had stroke actually been diagnosed, Mr. Hasan would have received earlier treatment, which the plaintiffs argued would have likely resulted in a good outcome, as opposed to the permanent deficits he ended up suffering.
Because of the defendant’s negligence, CTA was not done, and no one could say for certain what the CTA actually would have shown had it been done at the right time. It was possible that the CTA would have revealed damage that was incurable, partially curable, or wholly curable but there was no way to know for certain. The defence argued that because the Plaintiff had not provided critical evidence about the progression of the stroke, there was no basis for the trial judge to have reached the finding that earlier treatment would have actually resulted in a better outcome. The problem with this argument, which the Court of Appeal was alert to, is that evidence of the progression of the stroke would have existed if a CT angiogram was performed, and the only reason it wasn’t was because of the Defendant’s negligence.
Citing a case called Sacks v Ross from 2017 that has become the starting point for the analysis on causation in missed/delayed diagnosis cases, the Court of Appeal found that the trial judge correctly applied the law by first determine what likely happened, and then determining what likely would have happened had there not been a breach of the Standard of care. In doing so, the Court of Appeal reiterated the longstanding presumption that if a gap in the evidence exists because of negligence, the negligent defendant cannot turn around and rely on this gap in the evidence to support their defence. In other words, a court can infer causation if the defendant’s own negligence prevents the plaintiff from demonstrating the causal link. It’s up to the defendant in that case to provide evidence to rebut that inference.
The verdict in favour of the deserving Plaintiff was upheld.
