Saddleback Church pastor Rick Warren is in the hospital undergoing tests to determine the cause of pain in his arms and numbness in his fingers.
In an email to congregants Tuesday, Warren said he had begun feeling unwell over the weekend, and that pain and numbness set in Monday night.
His doctor made a preliminary diagnosis Tuesday that an inner ear virus could be to blame, Warren wrote.
"Currently, the doctor's diagnostic guess is that an inner ear virus I picked up last week may have spread to the nerves in my neck and radiated down my arms," Warren said. "But that's just a guess until they do a full day of tests."
On Wednesday, Warren tweeted that he has been undergoing tests of major organs during his hospitalization.
Warren is the leader of the Lake Forest-based megachurch and a best-selling author.
The church announced Tuesday on its Twitter feed that an event at the Lake Forest campus called Vision Night, scheduled for Tuesday and Thursday, had been postponed.