PORTLAND, Ore. -- A child remained in critical condition in the pediatric ICU at Emanuel Hospital Wednesday as he was treated for swelling on the brain, deputies said.

Deputies arrested a man on assault charges after the 5-month-old boy was taken to a hospital with serious injuries.

Deputies from the Clark County Sheriff's Office said the baby was brought to the Pediatric Critical Care Unit at Legacy Emanuel Hospital at about 5:30 p.m. Sunday.

Deputies said the child was suffering from fractured ribs, a fractured arm and a subdural hematoma, which is described by WebMd.com as bleeding between the brain and skull.

The boy's fractures appeared to have happened before the head injury leading investigators to suspect there has been a history of child abuse, deputies said.

The baby had been suffering from seizures since being admitted to the hospital but they have been diminishing, deputies said. The infant has also begun to track movement better with his eyes.

After an investigation, Silvestre Luna Rodriguez, 27, of Vancouver, was arrested, deputies said.

Rodriguez appeared in the Clark County Superior Court on Tuesday where he was charged with two counts of second-degree assault. His arraignment is scheduled for 1:30 p.m. Nov. 7.

The relationship between Rodriguez and the child wasn't immediately clear.