The cause of death of a 28-year-old woman who died in hospital remains a mystery, an inquest heard.

The cause of death of Kirsty Tolley, from Walsoken, near King's Lynn, was originally believed to have been an epileptic fit with anaemia as a contributory factor.

An inquest in King's Lynn Coroners Court on Friday heard that Miss Tolley, who had severe learning difficulties, epilepsy, autism and anaemia, died at the Queen Elizabeth Hospital (QEH) on February 19, 2017, nine days after she was admitted.

Giving evidence in court, Dr Firas Hiddadin, consultant in endocrinology at the QEH, said Miss Tolley had bruising and pain on her leg, PV bleeding and a very low blood count.

Due to her iron deficiency, haematologist Dr Lisa Cook decided a blood transfusion could only be given to Miss Tolley if she had shown symptoms such as low blood pressure, fast heart rate or shortness of breath.

But Dr Hiddadin said there was no consistency with her blood pressure and that early warning signs fluctuated throughout the time she was in hospital, adding: 'Each time we saw Kirsty she never expressed any signs or symptoms.'

He said it was hospital policy to avoid blood transfusions due to the risks involved and so for her iron deficiency she was given her first dose of Ferrinject, an iron infusion, on February 16.

Her blood count continued to drop until another blood test taken at the time of death showed it had risen.

Dr Hidaddin said her death was unexpected, adding: 'I have never seen anything like this, it is so traumatising to lose a patient especially a younger patient.'

But an expert witness, Dr Martin Goddard, from the Royal Papworth Hospital, said the increase in blood count was too big a rise to happen in three days and that something else may have concentrated the blood.

He said after reviewing the post mortem and hearing the evidence in court, he determined the cause of death to be unascertained.

Dr Laszlo Igali, from the Norwich and Norfolk University Hospital who had conducted the post mortem, agreed with Dr Goddard and changed the cause of death to unacsertained.

He added: 'The anaemia, in my opinion, was significant at the time of death.'

Senior coroner Jacqueline Lake adjourned the inquest to give her verdict on Tuesday, April 8.