The 13-year-old died of peritonitis secondary to a ruptured gangrenous appendicitis in February, 2017.

He collapsed at home after a week of illness that included vomiting, severe diarrhoea, lethargy, loss of appetite, difficulty walking and an instance where he vomited brown liquid.

In the week before he died, Luca's family took him on two occasions to a Bay Medical Group surgery to see Dr Paul Bilokopytov, who told them on both occasions the teenager was suffering from viral gastroenteritis.

On the final day of the inquest into Luca's death on Wednesday, Ragni Mathur - the counsel assisting State Coroner Teresa O'Sullivan - said Luca had appendicitis on the second visit to Dr Bilokopytov, three days before his death, and was likely suffering from the condition during the first consultation two days earlier.

She said the evidence before the inquest was that Luca did not present with the "classic symptoms" of appendicitis.

"The evidence in my submission does support, on balance, a finding that, at a minimum, an insufficient history was taken and that there were deficiencies in the examinations which were conducted," she said.

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Ms Mathur told the inquest the "clear division" between the memories of Ms Degenhardt and Luca's sister Victoria as opposed to Dr Bilokopytov about whether he was told Luca had abdominal pain was a key issue for the Coroner to consider.

She said Ms Degenhardt began to write her statement only a week after Luca's death and called her memory "reliable".

And although Dr Bilokopytov's clinical notes were made the day of each visit, they were not a complete record of everything that was said and done during the consultations.

Ms Mathur said, on a conservative estimate, Dr Bilokopytov saw at least 50 patients between the time of Luca's first visit and his death five days later.

"That, in my submission, could affect any practitioner's memory as to what was said in a consultation and what was his thinking behind an entry made in a clinical record," she said.

Ms Degenhardt read to the inquest a moving letter she penned to her son after his death as family and friends watched from the public gallery, describing Luca as "my light".

"You believed in people, Lucs. And with that I will try my very hardest to believe that the right thing will happen here for you, because you so deserved better and the world lost a champion," she said.

"But my faith in you will never be lost. I know that you, as you did for every single person who knew you, will continue to change the world."

The inquest findings will be handed down on December 13.

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