The trial of a man accused of killing a three-year-old boy has heard the toddler did not die because of “one killer blow.”
Liam Whoriskey, of Glenabbey Gardens, Londonderry, denies the manslaughter of Kayden McGuinness in September 2017.
The 25-year-old also denies a further charge of child cruelty and one charge of child neglect.
Jurors heard from Dr Michael Farrell, a consultant neuropathologist at the Beaumont Hospital in Dublin.
He told Londonderry Crown Court that without a precise time of death, it was conjecture to determine which of the injuries inflicted on the child’s scalp triggered a massive swelling of the brain.
Asked by defence barrister Ciaran Mallon QC about 15 bruises found on Kayden’s scalp, Dr Farrell said that timing and dating when the blows were inflicted was a very difficult and precise science.
The court heard it was not possible to say which of the injuries had triggered a swelling of the child’s brain that resulted in the catastrophic bleeding and continued swelling of the brain.
“There was not, if you like, one killer blow”, Dr Farrell told the jury.
He said the “core of the pathological problem” was that the timing of Kayden’s death has not been ascertained.
Dr Farrell said he could not say how the injuries were caused but he said they were consistent with non-accidental injuries which precipitated a cerebral oedema.
Meningitis, a seizure, a heart or lung disease were ruled out as contributory factors to the child’s death, Dr Farrell told the court.
There was no evidence of poisoning nor of a renal disease, the court heard.
He said the blunt force trauma injuries to Kayden’s scalp could have been caused by someone grabbing the child by the head.
Dr Farrell said there was no fracture of the skull and that a single blow or a number of blows “can trigger a cascade of brain swelling.”
Asked by Mr Mallon if Kayden’s unusual behavioural pattern on the day before his body was found could indicate anything unusual, Dr Farrell said any alteration to behaviour of a child was consistent with concussion.
Under cross examination by prosecution barrister Peter Irvine QC, Dr Farrell said it was possible Kayden had been grabbed by the head but it was equally possible that he sustained multiple injuries to the head.
He told the court that tiredness in a child was also a symptom of concussion.
Dr Farrell said the defence and prosecution submissions in relation to the cause of death “are diametrically opposed.”
“We are all at the mercy of the clinical story,” he added.
Dr Farrell said he believed it was more likely than not that the scalp injuries were inflicted at the same time.
The trial continues.