Michael Jackson is suffering from a viral infection and had been ill for a week or more before he collapsed during a rehearsal this week, a doctor said Friday.
Dr. William Alleyne said diarrhea from the infection led to severe dehydration, which in turn dangerously quickened Jackson's heartbeat while lowering his blood pressure, causing his collapse.
Jackson remained in serious but stable condition in the intensive care unit at Beth Israel Medical Center North. His personal physician, Dr. Allan Metzger, said he could be hospitalized for at least another week while additional tests are done.
The doctors did not say whether Jackson's heartbeat was back to normal. He was still hooked up to a cardiac monitor and another machine that monitors oxygen content in the blood.
Metzger said the singer's condition was "serious but I wouldn't characterize it as life-threatening." However, Alleyne said Jackson's life had been in danger when he arrived at the hospital Wednesday night.
The doctors said there was no evidence of drug use.
Jackson, 37, collapsed at the Beacon theater while rehearsing for an HBO special that has since been postponed. Alleyne said Jackson had been ill for seven to 12 days before his collapse.
Jackson was disappointed about not being able to perform, he said.
"He tried to convince the medical team that he could give it a go," he said. "We put our foot down."
The doctors said Jackson had pictures of his family and his favorite Disney characters brought into his private room.
Jackson was visited Friday by his wife, Lisa Marie Presley-Jackson, and Diana Ross, his friend and mentor. Neither spoke to the horde of reporters outside the hospital.