Off-duty Edinburgh Royal Infirmary nurse Veronica Duncan, whose lost her own daughter months before, left her little victim less than three minutes from death, a court heard today.
Duncan even turned up at the hospital where the baby was fighting for her life but did not reveal what she had done as staff fought to save the child, the High Court in Edinburgh was told.
Advocate depute Alastair Brown said of the child's family: "They are angry that the accused was at the hospital whilst she was in a critical condition and that she was, in their perception, 'monitoring' the process of her dying when she could, by telling what she had done, have provided the information the medical staff badly needed."
The prosecutor said a doctor at Borders General Hospital, Shabana Khalid, "undoubtedly saved the baby's life" by instructing that dextrose be given to her after she was found to have very low blood sugar levels.
Duncan, 41, who has been detained in a psychiatric hospital in the Capital, was originally charged with attempting to murder the four-month old girl on March 7 this year.
But the Crown accepted her guilty plea to a reduced charge of assaulting her to her severe injury and to the danger of her life at a house in a village in Peebleshire.
Duncan repeatedly injected her victim with insulin – normally used in the treatment of diabetes – and caused her blood glucose level to drop inducing a state of hypoglycaemia which can cause brain damage or death.
Dr Brown said Duncan was a registered general nurse who worked at the intensive care department at ERI, where she had access to the hormone insulin. He said in May last year her own 16-month-old daughter Anna had died at their home in the Scottish Borders.
The advocate depute said Anna's death was caused by Purpura Fulminans – a haemorrhagic condition linked with previous infection. The child had caught chickenpox the week before and not recovered.
Dr Brown said Mrs Duncan's husband believed his daughter's death was linked to the MMR vaccination, and he blamed his wife for exposing her to chickenpox.
The prosecutor said the Crown accepted that Duncan was not functioning normally at the time of the offence, but she was criminally responsible for her actions.
On the day of the attack Duncan had called at the child's family home and invited her mother to go to a coffee morning.
She offered to dress the baby while the mother got changed to go out. Dr Brown said: "It appears that it was at this point that Duncan injected her insulin."
Later the victim's mum took her daughter and her other child to a swimming lesson. She began to notice something was wrong with the baby who was not waking up and whose eyes were not focusing. A family doctor was also at the pool and she asked him to look at her daughter.
An ambulance was called and on the way to Borders General Hospital the baby was given oxygen as it was thought she had suffered a seizure.
Dr Khalid was called to the hospital's accident and emergency department and the baby was found to be "drowsy, floppy and unresponsive".
The child was discovered to have three red spots in a triangle shape near her navel. It was later found this was where she had been injected.
A blood sugar test came back with a very low reading and Dr Khalid ordered dextrose to be administered.
"Before the dextrose could be administered she went into respiratory arrest and all available staff in accident and emergency were called to assist. At that point there was a three-minute window within which the child could be saved," said Dr Brown.
Attempts were made to ventilate her and she was given the dextrose and began to breathe on her own and wake up.
Duncan had turned up at the hospital where staff still did not know the underlying cause of the child's condition or how to treat it.
Dr Brown said: "She did not at any time say what she had done. Had she done so, it would have provided considerable assistance."
Over the next few days staff at the Borders hospital worked with consultants and scientists in Edinburgh on the case and a clinical chemist was able to identify a massive overdose of insulin which must have been injected.
Child protection measures were put in place and a police investigation was launched.
The child's mother was interviewed by police and the father also gave a statement. Their home was searched and the family computer taken for examination.
On March 19 Duncan's home was also searched and a box containing a syringe and insulin was found wrapped in scarves. More syringes were discovered in the bathroom and in a bedside drawer.
Duncan told police: "I do have insulin but it's not for what you think." She went on to explain it was for taking her own life.
She later admitted she had taken a syringe to the child's family home and injected the baby in the stomach.
Dr Brown said: "She was asked for an explanation as to why she had done this and could offer no explanation other than she was jealous and envious of the child's mother and the fact she had a healthy baby daughter."
He said that medical experts had confirmed that future problems for the victim were difficult to predict. She could have problems with speech, movement and memory.
Defence counsel Andrew Murphy said: "This is as highly exceptional and in some ways tragic a case as one might encounter in these courts."
He said psychiatrists had found Duncan was suffering from a mental disorder which fell short of a mental illness.
"She is abjectly apologetic to the family for the concerns and pains she has caused them and the sense of betrayal they may feel. All she can say is she was not herself at the time," he said.
Duncan, who sat crying in the dock as details of her crime were revealed, had sentence deferred on her for the preparation of background reports by Temporary Judge Roger Craik QC.
She will continue to remain at the Royal Edinburgh Hospital pending her next court appearance.