Eighteen doctors at CHOP are "perplexed and upset" that they could not determine a cause, she said. "They have no idea."
He was taken to CHOP in an ambulance sometime after 2 p.m. The counselor, a teacher and the child's brother, a seventh-grader at Jackson, accompanied him, the principal said.
Jackson does not have a full-time nurse, but one does come in every Thursday and every other Friday, said district spokesman Fernando Gallard. A certified nurse, who helped tend to the boy, was in the school as a volunteer at the time, Ciarianca-Kaplan said.
When asked if a nurse could have saved the child, Gallard said: "It's really unknown [since] we don't know what the medical condition is. What I can say is we had medically trained personnel in the classroom that provided CPR to the student."
He said he could not comment on whether the student had a pre-existing medical condition.
The first-grader, described as shy, funny and lovable, had been active yesterday morning. Later in the day, the student, whose name was not released, was accompanied to the bathroom by a classroom assistant, the principal said. On the way back, the two met up with a counselor in the hallway, Ciarianca-Kaplan said.
The trio walked down the hall together and, suddenly, the student sat down on the floor.
"Are you being silly?" the counselor asked the child, according to Ciarianca-Kaplan. The child began making bird calls, the principal said.
But the counselor could see something was wrong and said, according to Ciarianca-Kaplan, "He didn't look right to me." The child began to pass out, the principal said.
The counselor immediately called 9-1-1, and within seconds a behavior specialist emerged from a classroom and began to administer CPR, Ciarianca-Kaplan said. The specialist is not a district employee, but works for a local behavior-health-care agency.
The counselor remained on the phone with dispatchers who gave instructions on what to do, she added. Emergency-medical services arrived five to eight minutes later and began to work on the child, who was breathing when he was taken from the building.
Jackson, a K-8 school of 459 students on 12th Street near Federal, was put on lockdown, which means "nobody leaves class and students must stay away from windows," the principal said. "None of the kids saw anything."
After the ambulance rushed the student to CHOP, a number of medical teams worked on the child, who died about 4:30 p.m.
"My staff was on point. They did everything right," Ciarianca-Kaplan said. "Whether there was a nurse there or not, it wouldn't have changed the outcome."
Education advocate Lisa Haver, a retired district teacher who lives a few blocks from Jackson, said parents should not have to worry about sending their kids to school when the nurse is not there.
"We're heartbroken to hear about the death of another child," she said. "We need to find out what happened and whether this child's death could've been prevented if the nurse had been there."
Gallard called the death "an extremely tragic situation for the staff and the school overall."
The staff feels confident "they did everything they could to support the child during the medical distress that he had," Gallard said.
The boy's death is the second this school year following a medical emergency in a district school. Laporshia Massey, 12, died in late September after suffering an apparent asthma attack at Bryant Elementary, where there was no nurse on duty.
Jackson will have bereavement counselors and psychologists on staff today.