Mia Lucas, 12, had underlying brain disorder, inquest told

A 12-year-old girl who died at a children’s unit after being detained under the Mental Health Act was suffering from a potentially treatable physical brain disorder, an inquest has heard.

Mia Lucas died at the Becton Centre in Sheffield on 29 January 2024 while suffering a mental health episode and had told staff she “wanted to go to heaven,” the inquest was told.

But blood test results showed Mia was suffering from autoimmune encephalitis – a brain inflammation than can cause psychiatric symptoms.

The jury at the Medico-Legal Centre in Sheffield was previously told there was likely no physical reason for Mia’s psychosis. But pathologist Prof Marta Cohen said the new results were “conclusive”.

Mia was admitted to the Queen’s Medical Centre in Nottingham on New Year’s Eve 2023 after attempting to get knives from the kitchen and saying voices were telling her to harm herself and her family.

She was later sectioned under the Mental Health Act, then transferred to the Becton Centre, a specialist unit for under-13s, on 9 January 2024.

Despite being under surveillance including hourly checks at night, Mia, from Arnold in Nottinghamshire, was found unresponsive in her room at about 23:30 GMT on 29 January and declared dead the next day.

Much of the evidence called at the inquest, which started last week, has centred on whether Mia had autoimmune encephalitis, a “rare and complex” condition that can lead to extreme psychosis, catatonia and seizures.

It is also extremely uncommon in children, the inquest heard.

Experts said Mia’s MRI scans came back “normal” but the inquest heard earlier that further tests, including a lumbar puncture to obtain spinal fluid, would have been beneficial.

Prof Cohen said the medical cause of Mia’s death remained “compression of the neck” but she added that this was caused by “acute psychosis”, which was triggered by “autoimmune encephalitis”.

An expert neurologist, who told the inquest earlier on Monday that he could only say it was “possible” Mia had the disorder but not “probable”, was recalled to the witness box following the new evidence to say it was now “definitive” that she had autoimmune encephalitis, and this was the cause of her psychosis.

Consultant paediatric neurologist Mike Taylor also said it was “quite concerning” that further tests were not obtained at Queen’s Medical Centre, but he said he understood the difficulties the doctors were facing.

He added that treatments for autoimmune encephalitis could have severe side effects, up to and including death.

The jury has heard how Mia’s behaviour got worse and her personality changed in the months leading up to New Year’s Eve, and how she had a virus in December, which is a known cause of autoimmune encephalitis, although very rare.

Mia’s mother, Chloe Hayes, wiped away tears as Prof Cohen presented her new evidence, along with a number of members of her family.

Ms Hayes has described previously how her daughter was interested in singing, drawing, crafts and horse riding, and how she had ambitions to either open her own beauty salon or become a vet.

The inquest continues.