MARTINEZ -- A County Jail nurse remained hospitalized Tuesday after an inmate on Monday faked a seizure and then violently struck her in the head with a table lamp, Sheriff Warren Rupf said.

El Cerrito resident Aaron Nygaard, 34, was booked into the jail early Monday after being arrested by El Cerrito police on burglary charges, and now faces charges of assault with a deadly weapon for attacking the nurse, according to the Sheriff's Office.

Officials are not identifying the nurse and would not disclose her condition Tuesday. Rupf said she was knocked unconscious during the attack, but that the injuries do not appear to be life-threatening.

"I have no reason to believe that she won't fully recover," Rupf said.

The fracas began about 4 p.m. when jail medical staff were called to the holding cell in the Martinez Detention Facility on Ward Street to tend to Nygaard, who appeared to be suffering from a seizure, the Sheriff's Office said. After he appeared to stabilize, he told a nurse that he faked the seizure to avoid sitting in a particular room while he awaited assignment to a jail module.

Then, without provocation, Nygaard picked up a lamp that a medical staff member had brought to the nurses station to better read documents and struck the attending nurse in the head, authorities said. Nygaard was swinging the lamp and fighting with deputies before he was eventually restrained by use of a Taser and physical force. Rupf said Nygaard had to be sedated before he was taken to a hospital.

The nurse was taken to a different hospital -- John Muir Medical Center in Walnut Creek. She is a longtime employee with Contra Costa Health Services, which contracts medical services at the jail.

"We are deeply concerned about her, and our thoughts and prayers are with her and her family," said Anna Roth, chief executive officer of CCHS' Contra Costa Regional Medical Center and Health Centers. "Staff safety is a high priority and we are working closely with the Sheriff's Office on this investigation."

Rupf said there was nothing about Nygaard that would have indicated he was going to attack anyone at the jail.

Before the incident, he had not exhibited any aggressive behavior and appeared "calm and collected," Rupf said. Nygaard has no previous criminal record.

Rupf said the Sheriff's Office will re-examine jail operations to see if safety improvements are warranted. The jail, which can legally house as many as 695 inmates, contained about 650 on Monday. There were about 48 attacks on jail staff in 2009, and none of them were on medical workers.

"This is a highly unusual event -- one that, at this point, defies explanation," Rupf said.

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