A boy died after he was taken by ambulance to an A&E department almost 20 miles from his home following a decision to reduce children’s services at his local hospital because of staff shortages.

The death of Callum Cartlidge, eight, who had a cardiac arrest at his home in Redditch, Worcestershire, prompted hundreds of people to take part in a march to remember him and protest at cuts to the town’s Alexandra hospital.

Callum’s inquest heard he had been sent home the day before the cardiac arrest after being diagnosed with tonsillitis. A postmortem found he had Addison’s disease, a rare and potentially life-threatening condition.

Before the start of a five-day inquest at Worcestershire coroner’s court in Stourport-on-Severn, Callum’s parents, Stacey and Adie, said they were desperate for answers.

“Our family has been left devastated by Callum’s death,” they said in a statement. “We find each day a struggle not knowing why he died.

“While the inquest is going to be difficult, our family need to know if anything could have been done to prevent Callum’s death, and if so, what measures will be put in place so other families do not have to go through the heartache we have had to experience.” Callum left behind a twin brother, a sister and a younger brother.

A few days before his death, Callum was diagnosed with tonsillitis and given penicillin, but his condition deteriorated. On 2 March last year, he was taken to his GP with vomiting and dehydration.

From there, he was sent by ambulance to Worcestershire Royal hospital. He was dischargd at 11pm and returned home. The next day, Callum had a cardiac arrest.

Paramedics rushed him to Worcester in 23 minutes, but he died shortly after arriving. Callum lived two miles away from Alexandra hospital, but it had stopped taking paediatric emergencies because of a shortage of doctors.

Susan Tonks, an advanced nurse practitioner who examined Callum at Winyates health centre in Redditch on 28 February, diagnosed him with tonsillitis.

“He looked a bit frightened. I understand what Addison’s disease is now – I didn’t know what it was at the time. He looked like an ill child with tonsillitis,” she told the inquest.

Callum returned to the surgery on 2 March, when he was seen by Dr Ikram Ul Haq. In a statement, he said: “[Callum] had sunken eyes, he was floppy, very lethargic. I called 999 and asked for an ambulance.”

Zara Oliver, a paediatric nurse in A&E at Worcestershire Royal, who was on duty when Callum was admitted, said: “He was in mild to moderate discomfort. He was pale and looked dehydrated, he was just sat on the trolley.

In September 2016, a paramedic expressed concern that children from the Redditch area were being taken to hospital in Worcester or Birmingham, rather than the Alexandra.

“Our concern if we’re in trouble with a child – a cardiac arrest or a child’s got a bad asthmatic attack or having a fit – is if we can actually just go to the hospital department to get the child stabilised before we move to the other hospital. We’ve been told we’re not allowed to do that,” Stuart Gardner told the BBC.

The month after Callum’s death, up to 500 people took part in a march to remember him and protest about cuts to services at the Alexandra. His father spoke of his distress of the ambulance passing the hospital on the way to Worcester.

The inquest continues.