A postmortem found she had acute myeloid leukaemia.
More than eight years later, Hineihana’s mother Tracey Elvins - who spent 17 years with her former partner trying for a child - is still fighting.
"I just don’t want them to get away with it. My life would have been so much different had this not happened," she said.
"It sounds like a s... thing asking for money but it’s not really. I had to survive and my mum helped me to do that. She fronted up with so much money for me."
Court documents her lawyers filed with the High Court in July, as well as those filed in response by the Southern District Health Board (SDHB), were recently released to the Otago Daily Times.
They reveal Ms Elvins is seeking $500,000 in damages, nearly $20,000 to cover Hineihana’s funeral and headstone, and costs.
"The defendant owed the plaintiff, as Hineihana’s mother, a duty of care to ensure that she did not suffer a psychiatric illness through nervous shock if Hineihana did not receive the expected standard of care and medical treatment," the statement of claim said.
It was opposed by the health board, which, in a brief statement of defence, wrote off much of the claim as "speculative".
SDHB lawyers also argued the legal action should be set aside because it had come more than six years after the incident and was thus barred by the Limitation Act.
The first hint of Hineihana’s poor health came a week before her death when she developed a cough and runny nose.
On September 26, 2013, she was at home from preschool, lost her appetite and was feverish.
A trip to Dunedin Hospital the next morning resulted in a discharge several hours later and a request for follow-up by the paediatrics department that never came.
The next night, Hineihana’s condition deteriorated but a consultant looked at her across the emergency department and considered her fit to be sent home.
Later, two lower-ranking staff members said they had concerns about the decision but felt unable to raise them.
Hineihana went into respiratory arrest the next day and resuscitation attempts were unsuccessful.
She endorsed measures the SDHB had put in place to address the shortcomings.
"The plaintiff has experienced intense grief and suffering. She has lost her purpose in life ... The plaintiff blames herself for Hineihana’s death.
"She reproached herself for not questioning the decision of the medical staff to discharge Hineihana on September 28.
"She is haunted by the fact Hineihana’s death was avoidable," Ms Elvins’ statement of claim said.
The case will next be called before the High Court in February and she was determined to see it through.
"The process of the whole thing has been horrendous. I’m just not letting it go."
Eight-year battle
Sept 2013: Hineihana Mausii dies at Dunedin Hospital.
Jun 2016: The Health & Disability Commissioner investigation results in censure of two doctors and a nurse, rules the SDHB team failed to provide appropriate care.
Jul 2019: Coronial inquest into Hineihana’s death takes place in Dunedin District Court.
Aug 2020: Coroner Brigitte Windley releases findings, says the case has implications for every DHB in the country.
Jul 2021: Lawyers for Tracey Elvins file paperwork with the High Court seeking more than $500,000 in damages.
