How do I determine if an employee’s De Quervain's disease is being “aggravated” at work?

According to 1904.5(b)(4), OSHA considers a pre-existing injury or illness as significantly aggravated, for purposes of injury and illness recordkeeping, when an event or exposure in the work environment results in any of the following:

• Death, if the pre-existing injury or illness would likely not have resulted in death but for the occupational event or exposure;
• Loss of consciousness, if the pre-existing injury or illness would likely not have resulted in loss of consciousness but for the occupational event or exposure;
• One or more days away from work, or days of restricted work, or days of job transfer that otherwise would not have occurred but for the occupational event or exposure; OR
• Medical treatment in a case where no medical treatment was needed for the injury or illness before the workplace event or exposure, or a change in medical treatment was necessitated by the workplace event or exposure.