A man accused of stabbing an eight-year-old boy in the stomach with a syringe as he played in a Melbourne park may have an acquired brain injury caused by alcoholism.

Andria Stiscak, 75, made an application for bail on Wednesday following his arrest for the lunchtime attack, saying he had done nothing wrong.

The Carlton man is facing seven charges including recklessly placing the child in danger of death.

Police say Stiscak was in Fitzroy's Clondell Park, where the boy was playing with his little brother and a friend, when he allegedly swiped at the eight-year-old two or three times, stabbing him in the stomach with the syringe.

The boy felt the pin prick through his T-shirt, and when his mother, who was also in the park, asked him if the man had touched him, he said "yes", Detective Senior Constable James Heenan told the bail hearing.

At the Royal Children's Hospital an examination detected a red dot under his belly button, Det Sen Const Heenan said.

He has been placed on heavy, high risk HIV medication but Detective Senior Constable Heenan said it was reacting badly with the boy's diabetes treatment.

"He's taken a turn," Detective Senior Constable Heenan told the Melbourne Magistrates Court.

"He's not feeling well and he's missing school."

The boy's mother said the attacker was carrying a syringe as he walked away.

He was mumbling to himself and had a heavy European accent.

Police arrested Stiscak on Monday and charged him with offences including assault, intentionally causing injury, recklessly causing injury and possessing a dangerous item.

Detective Senior Constable Heenan told Melbourne Magistrates Court Stiscak was not known to mental health service providers but it was possible he had an acquired brain injury caused by alcoholism.

Magistrate Frank Jones said Stiscak looked like he was showing early signs of dementia.

Stiscak yelled out he had done nothing wrong as the hearing started.

"I want to go home, I never do anything wrong," Stiscak said.

"Nothing I do wrong, nothing."

He was remanded into custody and the matter was adjourned until May 28.

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