COURT OF APPEAL FOR ONTARIO
Copeland, Wilson & Pomerance JJ.A.
BETWEEN
Skyler Brown by her Litigation Guardian Jennifer Brown, Jennifer Brown and Jeff Brown
Plaintiffs (Respondents)
and
Brandon Meaney and Gabriel Ronen
Defendants (Appellants)
Darryl Cruz, Morgan Watkins, and Sam Rogers, for the appellants
Paul Harte, Joshua Harte, and Kristian Bonn, for the respondents
Heard: November 4, 2025
On appeal from the judgment of Justice Michael Bordin of the Superior Court of Justice dated December 30, 2024, with reasons reported at 2024 ONSC 7256.
A. Overview
1Skyler Brown (“Skyler”) was born on December 20, 2002 with a rare condition called pyridoxine-dependent epilepsy (“PDE”). Three and a half months later, in April 2003, she began experiencing seizures. Her parents took her to the local hospital. On May 9, she was transferred to McMaster Children’s Hospital (“MCH”) – a quaternary hospital capable of providing Skyler with specialized care – and admitted to the Pediatric Intensive Care Unit. She came under the care of the appellants, Dr. Meaney and Dr. Ronen, who were pediatric neurologists.
2In the claim, the respondents alleged that the appellants were negligent in their treatment of Skyler between May and July 2003 and that, as a result, she suffered severe neurological injuries and resultant intellectual and developmental delay. The appellants denied any negligence in their provision of care to Skyler.
3The action proceeded to trial on the issues of liability and causation, the damages having been agreed upon between the parties. The trial judge rendered a judgment for the respondents, finding that the appellants were negligent and that their negligence caused Skyler’s injuries.
4The appellants appeal, arguing the trial judge erred in three ways: (i) by creating his own standard of care; (ii) in his treatment of the issue of informed consent; and (iii) in his analysis of causation. I do not accept the trial judge made the alleged errors and, for the reasons that follow, would dismiss the appeal.
B. Background Facts
5Many of the facts relevant to this appeal were not in dispute at trial. It was agreed that there are many medical conditions that can cause seizures in babies. In 2003, PDE was a rare but known seizure disorder caused by an inability to metabolize vitamin B6. It generally has its onset within days of birth; but in some atypical cases, the seizures do not start for weeks or months after birth. Skyler has this atypical variant of PDE.
6There was no definitive test for PDE, nor any formal guidelines for treatment, in 2003. However, it was a known diagnosis, and medical residents were taught about it. It was treated with pyridoxine (also known as vitamin B6).
7At the time of these events, if an infant was not responding to the standard anti-seizure medications, PDE would be considered as a possible diagnosis. Diagnosis involved an empirical trial, typically comprised of three phases. In the first phase (the “challenge phase”), the baby would be given pyridoxine. If a positive response was noted, pyridoxine would then be withdrawn and a period of observation would occur (the “withdrawal phase”). If and when the seizures returned, pyridoxine would be restarted to confirm its positive effect (the “rechallenge phase”). There was no clear consensus on the dose of pyridoxine to be administered or the appropriate length of each of these three phases. In atypical cases, a longer withdrawal phase and/or several trials might be necessary.
8Skyler was admitted to MCH on May 9 and assessed by Dr. Meaney on May 11. He prescribed phenobarbital (a commonly prescribed anti-seizure medication) and she was intubated using propofol. After intubation, the seizures stopped. Although he considered a PDE diagnosis to be unlikely, Dr. Meaney ordered an empirical trial. The challenge phase of the trial was started by administering pyridoxine.
9Dr. Ronen assumed care for Skyler on May 12. She was on pyridoxine, as well as conventional anti-seizure drugs, and was not experiencing any seizures. From May 12 to May 16, Skyler was stable. Pyridoxine was discontinued on May 16, slightly less than four days after initial administration, thus beginning the withdrawal phase of the trial. Skyler continued to take traditional anti-seizure medications. Dr. Ronen ordered that she remain at MCH until May 20 for observation to see if her seizures would return.
10Dr. Meaney assumed care again on May 20. Skyler had not had any seizure recurrence. As a result, Dr. Meaney concluded that the pyridoxine had not been effective and, instead, that the traditional anti-seizure medications were controlling Skyler’s seizures. He informed Skyler’s mother that pyridoxine had not worked. Skyler was discharged from MCH and was seizure-free for 14 days.
11From May 26 to July 6, Skyler experienced multiple seizures. She reattended several times at the local hospital and was given traditional anti-seizure medications. At times, these medications appeared to be effective. On July 6, Skyler was admitted once again to MCH. Phenobarbital was not controlling her seizures. Dr. Meaney and Dr. Ronen prescribed traditional anti-seizure medications, of varying types and at increasingly high doses, in an attempt to stop them. They did not reintroduce pyridoxine, nor did they even consider doing so. On July 7, Skyler was placed in a drug-induced coma because her seizures could not be controlled. After other measures were not effective in eliminating the seizures, on July 16, Skyler was finally given pyridoxine. Her seizures stopped and she was discharged from the hospital on August 11.
12Subsequently, in 2008, after genetic testing was developed, Skyler’s diagnosis of PDE was confirmed.
13Prior to the events of July 2003, Skyler was developing well. There was no evidence of any significant brain injury on a May 2003 MRI, and her brain was growing at a normal rate. After July 2003, her brain growth slowed, and her parents reported that she was a “different baby” – she was lethargic, did not make eye contact, and was limp. A 2016 MRI revealed that she had suffered brain damage.
14At the time of trial, Skyler was 21 years old. She was non-verbal and could understand and follow only very simple directions. She required assistance with all her activities of daily living.
Reasons of the trial judge
15The trial judge determined that the appellants breached the standard of care when they concluded only three to four days after withdrawal, that pyridoxine had not been effective and when they failed to reinstate pyridoxine upon the return of Skyler’s seizures on May 26. It was known at the time that it could take much longer than three to four days for seizures to return after withdrawal; it could take weeks, particularly in atypical PDE cases like Skyler’s. It was thus unreasonable for the appellants to have concluded on May 20 that pyridoxine had been ineffective and to rule out that treatment option going forward. Although all parties agreed that the discharge of Skyler on May 20 was appropriate, this did not relieve the appellants of their obligation to continue to monitor Skyler’s response to the withdrawal of pyridoxine and, if necessary, to reintroduce it.
16The trial judge also found the appellants breached their duty to obtain informed consent when they failed to provide Skyler’s parents with information about the pyridoxine trial. Skyler’s mother was told that Skyler was being put on pyridoxine but not told why or what the pyridoxine trial entailed. The parents were not advised that their daughter was seizure-free after starting pyridoxine in May 2003, nor were they told, after the seizures resumed, that consideration should be given to restarting pyridoxine. Without information concerning the potential for pyridoxine to stop the seizures, Skyler’s parents could not make an informed decision concerning her treatment. The trial judge found that, had they been properly informed, they would likely have continued the pyridoxine on May 16 and certainly would have restarted it when the seizures returned. Pyridoxine is a virtually harmless vitamin, with at least the potential to have a significant benefit. And it was Skyler’s mother – not the appellants – who eventually raised the possibility of retrying pyridoxine, after conducting her own research.
17Finally, the trial judge concluded that, on a balance of probabilities, there was a causal link between the appellants’ breaches of the standard of care and the injuries suffered by Skyler. Had she been given pyridoxine prior to July 6, 2003, he found she would not have suffered the repeated seizures which injured her brain, nor experienced the drug induced coma which negatively impacted her neurological function.
C. ISSUES
i. Standard of Care
a. Positions of the Parties
18The appellants argue that the trial judge erred in setting the standard of care himself, instead of accepting the opinions of the experts who testified. They submit that the trial judge took a “black-and-white, formulaic approach to the treatment of seizures” – a standard of care not articulated by any of the experts, nor pleaded by the respondents. In making this argument, the appellants place significant emphasis on the trial judge’s statement that “Dr. Meaney and Dr. Ronen breached the standard of care in setting and implementing an observation period of three to four days for recurrence of the seizures”. They say that this statement is reflective of palpable and overriding error, because it was not the case that the appellants ever “set” an observation period, and legal error, because none of the experts testified that the standard of care required a precise observation period. The appellants submit that they were engaged in the exercise of clinical judgment and that their judgment call, on May 20, that the possibility of Skyler having PDE was very unlikely, was reasonable in the circumstances.
19The respondents submit that the trial judge’s conclusion regarding the standard of care was grounded in the respondents’ expert evidence, which the trial judge preferred. The experts explained that a properly conducted empirical trial required three phases: challenge, withdrawal, and rechallenge. The appellants did not perform the third phase, electing instead to abandon the trial on the basis of an erroneous and unreasonable conclusion that pyridoxine was not effective.
b. Analysis
20In an action for medical negligence, the claimant must prove what the standard of care was at the time of the events, that the defendant professional breached that standard of care, and that the breach caused some damage.
21The standard of care for a medical practitioner is that of a reasonably prudent practitioner with the same level of experience and in similar circumstances: Crits v. Sylvester (1956), 1956 CanLII 34 (ON CA), [1956] O.R. 132 (C.A.), at pp. 142-143, aff’d 1956 CanLII 29 (SCC), [1956] S.C.R. 991. For specialists such as Dr. Meaney and Dr. Ronen, the standard of care that their actions are to be measured against is that of reasonably prudent specialist in the same field – here, pediatric neurology: ter Neuzen v. Korn, 1995 CanLII 72 (SCC), [1995] 3 S.C.R. 674, at para. 33. The standard is not one of perfection nor even excellence. Moreover, the actions of Dr. Meaney and Dr. Ronen must not be judged with the benefit of hindsight and the knowledge of PDE that is available today: ter Neuzen, at para. 34.
22In negligence cases involving professionals, expert evidence is generally required to establish the standard of care, as it is beyond the knowledge of the average person: Flood v. Boutette, 2021 ONCA 515, 460 D.L.R. (4th) 648, at para. 72. Trial judges cannot generally set the standard themselves. Contrary to the appellants’ submission, however, that is not what happened here.
23The trial judge’s conclusion on the standard of care was that it required the appellants to have continued to monitor Skyler beyond the three to four day window that Skyler was kept in hospital. If and when seizures returned, they were obliged to reinstate pyridoxine. It was unreasonable for them to have disregarded the possibility that pyridoxine had been effective only three to four days after withdrawal and rule out this treatment option going forward. This standard of care was articulated by the experts.
24All of the experts testified on how an empirical trial was to be conducted. They agreed that, typically, an empirical trial involved three phases: challenge, withdrawal, and rechallenge. Although, as the trial judge recognized, none of the experts suggested that there were clear guidelines on dosing and timelines for these three phases, it was clear that each of the phases was important. Without the withdrawal and rechallenge phases, diagnosis could not be confirmed, particularly if there were potentially confounding medications involved. While, at times, one or more of the phases would be omitted,1 what one could not do is draw any strong conclusions regarding the efficacy of pyridoxine without completing each phase of the trial.
25One of the respondents’ experts, Dr. Wiznitzer, and one of the appellants’ experts, Dr. Prasad, also testified that it was known at the time that it could take more than a few days for seizures to return post-withdrawal. Particularly in atypical cases of PDE like Skyler’s, it could take weeks for seizure recurrence. As a result, a longer period of observation or the use of multiple trials was sometimes required.
26Given this expert testimony, it was open to the trial judge to find that the appellants had breached the standard of care when they concluded on May 20 – three to four days after withdrawal – that pyridoxine had not been effective and ruled out that treatment option going forward. They had, on that date, not completed the trial. No firm conclusions could be drawn regarding the efficacy of pyridoxine, particularly given the very real possibility that Skyler’s PDE was atypical and that it might take longer than a few days for her seizures to return. The trial judge’s conclusion that the appellants ought to have reintroduced pyridoxine upon seizure recurrence, either as a means of completing the rechallenge phase of the first empirical trial or through conducting a new trial, is unassailable. There is no basis for the appellants’ contention that the trial judge made up his own standard of care.
27Nor is there any basis for the appellants argument that the standard of care that the trial judge accepted was not pleaded. It is true that the statement of claim does not specifically plead that setting a three to four day observation period following the withdrawal of pyridoxine was negligent. However, the claim pleads the appellants failed to conduct an appropriate pyridoxine trial and failed to reconsider a diagnosis of PDE in a timely way. The trial judge’s findings on liability are rooted in exactly those allegations.
28While the trial judge’s statement that the appellants had “set” an observation period may not be entirely accurate, the fact remains that the appellants did conclude on May 20, three to four days after withdrawal, that pyridoxine had not been effective. In referencing a three to four day observation period, the trial judge was simply noting the amount of time it took the appellants to conclude that Skyler did not have PDE. He was not finding that there was a precise observation period that was required or that running an empirical trial was merely a matter of implementing an algorithm. In other words, his reference to an observation period was descriptive, not prescriptive.
29It is clear that the appellants were engaged in an exercise of clinical judgment in their treatment of Skyler; all of the experts agreed on that. The appellants were operating in an urgent and complex situation which required them to continue their attempts at addressing her seizures through various conventional anti-seizure medications. In these circumstances, the appellants cannot be faulted for a merely wrong judgment call. For liability to attach to their conclusion that pyridoxine had not been effective and should not be a possible treatment option going forward, it must have been an unreasonable conclusion in all of the circumstances. The trial judge found that it was. This finding was grounded in the expert evidence and is entitled to deference. There is no basis to interfere with it.
ii. Informed Consent
a. Positions of the Parties
30The appellants contend that this is not an informed consent case. If the appellants did not think that pyridoxine was a viable treatment option – in the sense that it was not clinically indicated and would not provide any benefit to Skyler – they cannot have been expected to inform Skyler’s parents about it. To the extent the appellants’ conclusion that pyridoxine was not a viable treatment option was unreasonable, it could give rise to liability for a failure to appropriately diagnose and/or treat Skyler. However, it should not also give rise to liability for a breach of the duty to obtain informed consent. The appellants submit, further, that the trial judge erred in failing to evaluate the materiality of the possibility that Skyler’s condition could be treated with pyridoxine. The rarity of PDE, combined with the nature and onset of Skyler’s symptoms, made PDE an extremely unlikely diagnosis. The possibility that her condition could be treated with pyridoxine, the appellants say, was therefore immaterial.
31The respondents submit that the appellants’ breach of the standard of care, in failing to recognize that pyridoxine would be an appropriate treatment, cannot relieve them of their duty to disclose this treatment option. Doctors are required to disclose not just what they know, but also what they reasonably ought to know. The respondents reject the appellants’ contention that the trial judge did not address materiality. His conclusion that “[a]ny reasonable person in the position of Skyler’s parents would want to know [about the risks and benefits of pyridoxine]” was a finding of materiality.
b. Analysis
32The duty to obtain informed consent requires physicians to disclose the nature of a proposed treatment, any material risks and benefits associated with it, and other reasonable alternatives to it, so that the patient can make an informed choice: Denman v. Radovanovic, 2024 ONCA 276, 495 D.L.R. (4th) 444, at para. 45. Whether a risk is material is to be determined on an objective basis, asking whether a reasonable person in the patient’s position would want to know of the risk: Ciarlariello v. Schacter, 1993 CanLII 138 (SCC), [1993] 2 S.C.R. 119, at p. 133. The extent to which a doctor is required to disclose alternative options for treatment depends on “a myriad of factual circumstances”: Van Dyke v. Grey Bruce Regional Health Centre, (2005), 2005 CanLII 18841 (ON CA), 255 D.L.R. (4th) 397 (Ont. C.A.), at para. 67, leave to appeal refused, [2005] S.C.C.A. No. 335. It goes without saying that a trial judge’s determination of this issue will be given significant deference in this court.
33A doctor does not avoid liability for a breach of the duty to obtain informed consent simply through a lack of knowledge of the material risks associated with a treatment or the reasonable alternatives to it. Physicians are required to disclose risks, benefits, and alternatives “known or which should be known” to them: Hopp v. Lepp, 1980 CanLII 14 (SCC), [1980] 2 S.C.R. 192, at p. 196; see also Van Dyke, at para. 69. While a plaintiff is not entitled to double recovery, that does not mean that liability cannot sound in both a negligent failure to diagnose or treat the plaintiff and a breach of the duty to obtain informed consent. The appellants’ first argument on this ground thus fails. The trial judge found that the appellants had neglected to disclose a reasonable alternative to traditional anti-seizures medications: pyridoxine. This constituted a breach of the duty to obtain informed consent: Van Dyke, at para. 76. The trial judge’s finding on this ground cannot be displaced by reliance on the appellants’ negligent view that pyridoxine was not a viable treatment option.
34The appellants’ second argument on this ground is similarly without merit. The trial judge addressed the issue of materiality and specifically rejected the argument the appellants now make on appeal: that the possibility Skyler had PDE was so low that they need not have disclosed it. The trial judge found that the appellants failed to discuss the pyridoxine trial with Skyler’s parents: why Skyler had been given pyridoxine, how the trial was supposed to work, that Skyler had been seizure free while on pyridoxine, that pyridoxine could be resumed if her seizures returned, and the potential risks and benefits of doing so. As the trial judge found, this was all information that any reasonable person in the position of Skyler’s parents would want to know.
iii. Causation
a. Positions of the Parties
35The appellants submit that the trial judge erred in concluding that Skyler’s brain damage was caused by the seizures she experienced in July 2003 when there was no evidence of that in the record. They argue that the expert evidence reflected that only prolonged seizures – those lasting more than 45 minutes – could cause brain damage and that there was no evidence that any of Skyler’s seizures lasted this long.
36The respondents argue that there was more than enough evidence for the trial judge to conclude that Skyler’s injuries were caused by the appellants’ negligence. The expert evidence reflected that a seizure lasting 45 minutes was one mechanism through which brain damage could occur, not the only mechanism.
b. Analysis
37The appellant’s argument on this ground, which was not raised in oral submissions, may be dealt with briefly. I agree with the respondents that the expert evidence accepted by the trial judge was not that brain damage could only occur through a seizure lasting more than 45 minutes. Rather, this was one mechanism through which brain damage could occur. Although the experts did not clearly point to another mechanism of injury, it was not necessary for them to have done so. Causation need not be determined by scientific precision: Snell v. Farrell, 1990 CanLII 70 (SCC), [1990] 2 S.C.R. 311, at p. 328. A trier of fact need not come to a single firm conclusion regarding the precise mechanism of injury: Cheung v. Samra, 2022 ONCA 195, 467 D.L.R. (4th) 708 at para. 53, leave to appeal refused, [2022] S.C.C.A. No. 144. The respondents’ burden was merely to show that, on a commonsense basis, but for the appellants’ negligence, Skyler’s injuries would not have occurred. The trial judge determined that this burden had been satisfied.
38There was more than enough evidence for him to have done so. Before July 2003, Skyler was developing well and her brain growth was normal. She showed no signs of brain damage on a May 2003 MRI. After July 2003, her brain growth slowed and her parents reported noticeable changes in her behaviour. 2016 imaging demonstrated that she had suffered a brain injury.
39Contemporaneous medical records indicate that the appellants themselves were concerned about brain injury and warned Skyler’s parents at the time of these events that the repeated seizures Skyler had experienced may have caused permanent damage.
40Finally, there was evidence of what might have occurred in the “but for” world: Skyler’s sister, who also has PDE and was treated promptly with pyridoxine, did not sustain a brain injury and has not suffered from the same intellectual and developmental delay. Instead, her development has been uneventful and she has met the usual milestones.
41As Dr. Wiznitzer testified, and the trial judge accepted, this was all evidence of causation, even if it did not speak to the precise mechanism through which Skyler’s brain damage occurred. Taking a commonsense approach to causation, the trial judge was entitled to conclude that causation had been made out: that but for the appellants’ negligence Skyler likely would not have sustained the brain injury that she did and likely would not have suffered from resultant developmental and intellectual delay. It was not necessary for the trial judge to resolve the issue of whether the brain injury resulted from a single prolonged seizure, successive seizures, the induced coma, or some combination of the three.
D. A Note on Brevity
42I conclude by briefly expressing a concern with the reasons in this case. This was a 12-day trial with only liability in issue. The trial judge’s reasons are 125 pages in length. This is unnecessarily long and includes much repetition of the evidence. I echo the comments of my colleague, Lauwers J.A., in Welton v. United Lands Corporation Limited, 2020 ONCA 322, 64 C.C.E.L. (4th) 265, at paras 56-63. Reasons should not be a “factual data dump” or an “extended ‘note to self’”.
E. Disposition
43The appeal is dismissed. Costs are payable to the respondents in the agreed upon amount of $75,000, all inclusive.
Released: June 19, 2026 “J.M.C.”
“D.A. Wilson J.A.”
“I agree. J. Copeland J.A.”
“I agree. R. Pomerance J.A.”