A 12-year-old girl who died after an incident of self-harm was failed on multiple levels, an inquest jury has found.
Warning: This story contains references to self-harm and suicide
Mia Lucas, who died in January 2024, was found unresponsive at an NHS children's psychiatric unit after developing a rare neurological disorder that had been left undiagnosed.
The jury at Sheffield Coroner's Court heard the girl was found at the Becton Centre, part of Sheffield Children's NHS Foundation Trust.
She had been placed there after being sectioned while suffering an "acute psychotic episode" during an assessment at the Queen's Medical Centre (QMC) in Nottingham.
On Thursday, the jury found that the failure to undertake a lumbar puncture at QMC before her transfer to the Becton Centre "possibly contributed to Mia's death".
A lumbar puncture involves a needle being inserted into your lower back to find out if symptoms are caused by a brain or spine condition.
The jury also said there was a failure at the Becton Centre to respond adequately to Mia's risk of self-harm.
Professor Marta Cohen told the jury Mia's cause of death was "compression of the neck" but she had now added that this was caused by "acute psychosis", which was caused by "autoimmune encephalitis", an inflammation of the brain that can cause extreme psychiatric symptoms and is treatable.
The autoimmune encephalitis diagnosis emerged during the nine-day inquest after a pathologist revealed she had received new post-mortem results.
The revelation prompted shock in the courtroom and tears from Mia's family members in the public gallery.
The condition was described as "complex and rare", according to consultant paediatric neurologist Mike Taylor.
He added that there was a low level of suspicion Mia had it, while being assessed at QMC, and told the court that experts had to consider the very severe treatment side effects, which included death.
Mia's mother, Chloe Hayes, told Sky News she was unhappy at how the Becton Centre had supervised her daughter.
"All they had to do was watch her. I actually never got told the truth about the attempts that Mia made [to self-harm] until after she died," she said.
"If I'd have known the truth I wouldn't have left Mia there. And I think she had so much to live for. I don't think she knew what she was doing."
In a statement, Mrs Hayes added that she wanted people to know her daughter's extreme behaviour was only evident in the final few weeks of her life.
"For the other 12 years, she was a beautiful soul who loved life and loved her family, and that's how we want her to be remembered," she said, describing Mia as a "happy, fun, friendly girl who had so much to live for."
NHS Trusts apologise for Mia's death
In a statement, Dr Manjeet Shehmar, medical director at Nottingham University Hospitals NHS Trust, offered "heartfelt condolences to Mia's family for the loss of their daughter".
She continued: "We accept the coroner's outcome in court today and apologise to Mia's family for not identifying autoimmune encephalitis while she was in our care. While this is an incredibly rare condition and initial tests were negative, we recognise that further testing may have had an impact on her future, for which we are truly sorry."
Dr Shehmar said that in future cases of suspected possible autoimmune encephalitis, a lumbar puncture will be performed.
The trust will also "strengthen training and guidance for staff internally and review current published evidence of acute psychotic episodes in children and young people".
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Dr Jeff Perring, executive medical director at Sheffield Children's NHS Foundation Trust, said: "Our thoughts are with Mia's family and everyone who is grieving her loss in such tragic circumstances.
"We are deeply sorry for Mia's death and recognise the profound impact this has had on those who loved her."
The trust has carried out a thorough review of Mia's care and made "significant changes" at the Becton Centre, he added.
"We will continue to work with children, young people, their families and carers to listen to, learn and take action from their experiences.
"The inquest has been important to understand fully the circumstances surrounding Mia's death. We will now carefully reflect on the evidence heard and the coroner's conclusions to ensure we continue to provide safe and compassionate care."
Anyone feeling emotionally distressed or suicidal can call Samaritans for help on 116 123 or email jo@samaritans.org in the UK. Alternatively, you can call Mind's support line on 0300 102 1234, or NHS on 111.
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