Coroner Borrowdale found tiny particles from the crushed medication clogged blood vessels in her lungs, causing widespread blood clots and preventing more than half of the blood volume from reaching the lungs properly, ultimately leading to heart failure.
The inquest focused heavily on the role of Horrell’s boyfriend, Taylor Stewart, who was alone with her in their South Dunedin flat when she became critically unwell.
Borrowdale found Stewart had “materially assisted” Horrell with the injections and that “without that assistance Wynter’s death would likely not have occurred”.
However, the coroner stopped short of finding criminal intent, concluding neither Horrell nor Stewart understood the potentially fatal consequences of injecting oral medication intravenously.
“Wynter’s death was not intentional,” Borrowdale wrote.
“Rather, this was a death by misadventure: Wynter’s and Mr Stewart’s actions were deliberate [to dilute and inject the tramadol] but their effect [Wynter’s death] was accidental.”
The coroner was highly critical of aspects of Stewart’s evidence, saying his account “changed markedly over time” and that “in some key respects, I have found Mr Stewart’s evidence to be not credible”.
“I believe that Mr Stewart’s fluctuating evidence arises through a desire to minimise his involvement,” she said.
Friends and family described Wynter Horrell as bright, determined and outgoing before the rapid decline in her health during the final year of her life. Photo / Supplied
Horrell, originally from Oamaru, had been born 13 weeks prematurely and lived with multiple chronic health conditions, including cerebral palsy, Crohn’s disease, seizures and chronic pain.
Wynter had a positive and outgoing attitude and did well at school, becoming head girl of her Oamaru school in Year 8.
She completed NCEA Level 3, moved to Dunedin to study occupational therapy at Otago Polytechnic and was described as “thriving” before her health deteriorated sharply during 2021.
The court heard she became increasingly reliant on Stewart after the pair moved in together.
Borrowdale found Horrell had a tendency to misreport or “catastrophise” aspects of her health, including falsely claiming to family and others that she had sepsis and a perforated bowel.
“It is wholly implausible that Wynter could have been suspected of a perforated bowel or sepsis without medical documentation being created,” the coroner said.
“I find that, on these matters, Wynter must have known that what she was saying was untrue.”
Days before her death, Horrell unsuccessfully sought prescriptions for intravenous fluids, antibiotics and other medications to be administered at home through her portacath.
The coroner found no clinician had authorised that treatment or advised her to inject tramadol.
“Overall, I believe it would be extremely unlikely that any advice to administer Tramadol other than orally as originally prescribed would be given by Hospital staff,” Medical Director Dr Joel Papak told the inquiry.
Borrowdale accepted that evidence, writing: “I do not accept that Wynter’s statement about hospital advice was true”.
The inquest also identified shortcomings in the initial police investigation after officers incorrectly assumed Horrell had died of natural causes because of her extensive medical history.
Borrowdale said there were “unhelpful shortcomings in Police initial inquiries” that affected the investigation.
However, she declined to broaden the inquest into police conduct itself, saying post-death events were generally outside the scope of coronial proceedings.
The coroner found Horrell’s GP, Dr Donald MacKenzie, had not acted improperly in prescribing tramadol and had no reason to suspect it would be misused intravenously.
She also found clinicians had warned against using the portacath outside hospital settings.
Borrowdale said the case highlighted the need for stronger safeguards and patient education around central venous access devices.
Following Horrell’s death, Health NZ developed new guidelines for home intravenous therapy, including requirements that patients and caregivers acknowledge misuse of such devices “may result in life-threatening complications”.
A register has also been created recording patients authorised to self-access devices such as portacaths.
“The public should be aware that it can be lethal to intravenously inject any drug not formulated for intravenous use,” Borrowdale wrote, “and that they should take medications only as advised by their medical practitioner”.
Coroner Borrowdale extended her deepest sympathies to Horrell’s family and friends for their loss.
In a statement provided to NZME, Wynter’s mother, Aimee, said her family acknowledged the release of the coroner’s report.
“Losing Wynter unexpectedly at just 20 years of age has been devastating for our family. She was a deeply loved daughter, granddaughter, niece, cousin and friend – kind, caring, vibrant and full of hopes and dreams,” she said.
“Her passing has left an immense void in our lives that can never be filled. We are grateful to the coroner for the time and care taken to investigate the circumstances surrounding Wynter’s death.
“While this report cannot bring her back, it does provide some answers in helping us to attempt to better understand what happened. The unanswered questions and failings, we will carry with us for the rest of our lives.
“It is our sincere hope that the recommendations made will lead to any meaningful change and an investigation from the police to help prevent other families from experiencing such heartbreak.
“We would like to thank everyone who has supported us throughout this time. This has been an incredibly difficult journey and we ask for privacy and compassion as we continue to grieve.
“Wynter will always be loved and remembered. We carry her with us every day. Loved by all – forever in the stars.”
Ben Tomsett is a multimedia journalist based in Dunedin. He joined the Herald in 2023.