A THREE-YEAR-OLD boy who died in a small district hospital would have lived if he had been treated at a major paediatric centre, a coroner has found.

Releasing his report into the death of Curtis Whitting, John Abernethy said the nursing staff and junior doctors at Manly District Hospital "were unable to properly handle the confusing symptoms and signs (of Curtis's condition) as they unfolded".

"It is highly likely that had the child been admitted to a hospital with a major paediatric ward, the treatment would have been vastly different with a different outcome," Mr Abernethy said.

Curtis died on April 23 last year after suffering a fatal cerebral oedema, or swelling of the brain. He was taken to Manly Hospital in a lethargic condition on the morning of April 22, having vomited and complained about feeling sick the night before.

By the next morning he was dead – 25 hours after being admitted.

Mr Abernethy found that the oedema was caused by "complications of gastroenteritis and its treatment".

He said staff at Manly erred by not contacting head paediatrician Dr Annie Lim as Curtis failed to respond to treatment.

Resident junior Dr Andrew Booker ordered a doubling of Curtis's intravenous fluid intake about 4pm after diagnosing him as "moderately dehydrated".

But Mr Abernethy said: "There is a substantial body of evidence that it may have been unwise in the circumstances of this patient, with a diagnosis of moderate dehydration and a documentation of bed wetting whilst being re-hydrated, to double the fluid intake without reference to Dr Lim."

Another resident, Dr Michael Leonard, also failed to contact Dr Lim as Curtis's condition deteriorated.

"It is perfectly obvious Dr Lim did not know of events unfolding at Manly Hospital as she was not contacted by her residents until it was far too late," Mr Abernethy said.

Mr Abernethy made three recommendations in his report:

The Department of Health consider establishing a working party to develop a protocol for all medical staff involved in the care of children with dehydration;

The Department consider introducing requirements where junior staff must contact department heads before making IV fluid changes;

The occurrence of headaches in children with dehydration should be reported to senior medical officers.

Northern Sydney Area Health CEO Dr Stephen Christley said the service would consider the recommendations urgently. "We want to ensure this does not happen again," he said.

Outside Glebe Coroner's Court, Curtis's parents Marina and Craig said they were still finding it difficult to accept their son's death.

"He went to hospital with gastroenteritis and he never came home, which is very difficult to fathom," Mr Whitting said. He said he hoped such a tragedy could never happen again.