The heartbroken mother of Melbourne toddler Isabella Rees, who died after swallowing a button battery, has urged parents to speak up and be heard by doctors when worried about their child’s health.

Isabella died in February 2015 after 19 days of ill-health, having been sent home from hospital three times by doctors who had diagnosed her with a urinary tract infection.

On her fourth visit to Sunshine hospital’s emergency department, Isabella was found to have a foreign object – a tiny battery – in her oesophagus, but the discovery came too late and she soon died.

An inquest was held into Isabella’s death and on Thursday a coroner ruled the hospital’s medical care was “reasonable”.

Coroner Caitlin English noted the difficulty in diagnosing a battery ingestion, which can cause alkaline burn, internal ulceration and bleeding, but can show general symptoms of fever, vomiting and discoloured poo.

“The non-specific nature of symptoms following ingestion makes diagnoses, especially in young children, particularly difficult,” she said.

Parents Allison and Rob Rees had on several occasions told hospital staff that Isabella, known as Bella, may have swallowed something, the coroner ruled.

Those concerns about a potential swallowed item were not noted in medical records.

But English was not satisfied that the recording of these “vague” concerns would have changed Bella’s treatment.

“An incident of swallowing, gagging or choking was not witnessed,” she said.

In a statement outside court, Allison Rees thanked the coroner for her “sensitive and caring” approach to the inquest.

She hoped Bella’s story could prevent future battery button tragedies, saying the inquest highlighted issues around documenting parental concerns.

“We believe our beautiful Bella could’ve been saved, especially if early detection and intervention of a button battery ingestion was made,” she said.

“To all the parents and carers out there ... You know your child better than anybody.

“Make sure you voice your concerns. Make sure you are being heard. Because it just might save your child’s life.”

An x-ray is the “gold standard” for diagnosing swallowed batteries but doctors must be careful not to overuse them, the inquest heard.

“It’s kind of over-simplistic to think because the kid swallows something, we would necessarily get an x-ray or ultrasound,” Dr Ruth Barker, an emergency paediatrician from Queensland, told the inquest.

The coroner said button batteries seemed “innocuous when held in the hand” but are “extremely dangerous if ingested”.

“Their shiny, smooth surface makes them attractive to small children,” English said.

She supported the Australian Consumer and Competition Commission’s recommendation of law changes to bring in general safety provisions for consumer products.

“Such a law would impact on design, sourcing and supply of unsafe consumer products, including button batteries.”

She also recommended Kidsafe Victoria consider running button battery awareness campaigns, particularly around major events such as the Royal Melbourne Show, when children are more exposed to the products.

Western Health, which operates Sunshine hospital, welcomed the findings and again offered condolences to Isabella’s family.

“We have taken a range of steps since Isabella’s death to reduce the likelihood of such a tragic incident occurring again,’ chief medical officer Dr Paul Eleftheriou said.