Background
Skyler Brown was born in December 2002 with pyridoxine-dependent epilepsy (PDE), a rare seizure disorder caused by an inability to metabolize vitamin B6. When seizures began at roughly three and a half months of age, she was transferred to McMaster Children’s Hospital and admitted to the Pediatric Intensive Care Unit, where she came under the care of pediatric neurologists Dr. Brandon Meaney and Dr. Gabriel Ronen. Because PDE was a known but rare diagnosis in 2003, the accepted diagnostic approach was a three-phase empirical trial: a challenge phase (administering pyridoxine), a withdrawal phase (discontinuing it to observe for seizure recurrence), and a rechallenge phase (reintroducing pyridoxine to confirm efficacy).
The appellants initiated the pyridoxine trial but, only three to four days after withdrawing the vitamin on May 16, 2003, concluded on May 20 that pyridoxine had been ineffective and discharged Skyler. Her seizures returned between late May and early July. When she was readmitted on July 6, the appellants escalated conventional anti-seizure medications — including placing her in a drug-induced coma on July 7 — without reconsidering pyridoxine. It was only on July 16, after Skyler’s mother raised the possibility based on her own research, that pyridoxine was restarted. The seizures stopped immediately. Genetic testing in 2008 confirmed PDE. By trial, Skyler was 21, non-verbal, unable to care for herself, and had sustained documented brain damage attributable to the intervening seizure events.
At trial before Justice Bordin of the Superior Court of Justice (2024 ONSC 7256), the parties agreed on quantum; the trial proceeded solely on liability and causation. The trial judge found the appellants negligent on both standard of care and informed consent grounds, and found their negligence caused Skyler’s neurological injuries. The appellants appealed on all three findings.
The Court’s Holding
The Court of Appeal (Wilson J.A., Copeland and Pomerance JJ.A. concurring) dismissed the appeal on all grounds. On the standard of care, the court held that the trial judge did not fabricate his own standard but grounded his finding in the expert evidence: all experts agreed that an empirical PDE trial required three phases, and both sides’ experts acknowledged that seizure recurrence after withdrawal could take weeks — particularly in atypical cases like Skyler’s. It was therefore open to the trial judge to find that concluding pyridoxine was ineffective after only three to four days of observation, and ruling it out as a future option, was unreasonable. The appellants’ characterization of the conduct as a permissible clinical judgment call did not displace the finding that the judgment was objectively unreasonable in the circumstances.
On informed consent, the court rejected the argument that because the appellants negligently believed pyridoxine was not viable, they had no obligation to disclose it. Physicians must disclose material risks, benefits, and alternatives that are known or reasonably ought to be known; a negligent failure to appreciate an option cannot serve as a shield against an informed consent claim. The trial judge’s finding that any reasonable parent in Skyler’s position would have wanted to know about the pyridoxine trial — what it entailed, that Skyler had been seizure-free on pyridoxine, and that it could be restarted — was a proper materiality determination entitled to deference.
On causation, the court affirmed that the but-for standard does not require identification of the precise mechanism of injury. The trial judge was entitled to take a commonsense approach: Skyler was neurologically intact before July 2003, her brain growth slowed and her behaviour changed dramatically afterward, and her sister — also diagnosed with PDE but treated promptly with pyridoxine — developed normally. The appellants’ own contemporaneous notes warned Skyler’s parents of the risk of permanent brain damage from the ongoing seizures, providing further support for the causal inference.
Key Takeaways
- A physician who prematurely terminates a diagnostic empirical trial and rules out a treatment option without completing the protocol may be found to have breached the standard of care, even in the absence of formal clinical guidelines, where expert evidence establishes that a reasonable practitioner would have continued monitoring.
- A negligent failure to recognize a treatment as clinically viable does not eliminate the duty to disclose that treatment option; informed consent obligations extend to alternatives the physician reasonably ought to have known about, not merely those actually known.
- Causation in medical negligence cases does not require scientific precision or identification of the precise injury mechanism — a commonsense inference from the before-and-after clinical picture, corroborated by contemporaneous records and comparator evidence, is sufficient to satisfy the but-for standard.
- The court took the opportunity to caution against unnecessarily lengthy trial reasons, echoing prior guidance that reasons should not be a “factual data dump” — a reminder with practical implications for trial management.
Why It Matters
This decision reinforces that physicians cannot immunize themselves from liability simply by characterizing a diagnostic or treatment decision as clinical judgment. Where expert evidence establishes that a reasonably prudent specialist would have continued a diagnostic protocol before drawing firm conclusions — particularly when the patient presents with an atypical variant of a known condition — courts will hold practitioners to that standard regardless of the uncertainty inherent in the clinical situation. The case is a significant reminder that premature diagnostic closure in complex pediatric cases carries serious legal consequences.
The court’s informed consent analysis adds an important doctrinal clarification: the duty of disclosure cannot be reduced by the physician’s own negligent reasoning. Allowing a negligent diagnostic conclusion to also eliminate the disclosure obligation would leave patients doubly disadvantaged — deprived of both proper treatment and the information needed to seek it elsewhere. For medical practitioners, this underscores the importance of transparent communication with patients and families throughout any diagnostic trial process, not only at the point of a final treatment decision.