The ER may say the crash aggravated an old back problem. The insurance company will use that same chart note and old MRI to argue "nothing new happened."

A common Broken Arrow example: your sister gets hit after a driver bounces through a pothole-rutted stretch during spring thaw, ends up at the ER with neck and low-back pain, and the scan shows a prior disc bulge. Her doctor says the collision made a stable condition symptomatic. The adjuster then circles every old complaint in her records and says she was already hurt before the wreck. If her current lawyer is letting that sit without pushing back, yes, she can switch lawyers mid-case in Oklahoma.

Here are the main rules:

• Oklahoma law does not let a driver off the hook just because the injured person had a prior condition. If the wreck worsened it, the at-fault party can be responsible for the aggravation.
• The insurance company only has a point as to the part she already had before. They are not supposed to avoid paying for the additional harm the crash caused.
• This is the basic eggshell plaintiff principle: the wrongdoer takes the injured person as they find them.
• The proof usually comes from before-and-after medical evidence: prior records, new symptoms, updated imaging, treating doctor opinions, work restrictions, and how her daily function changed after the crash.
• She can generally change attorneys before settlement or trial. The old lawyer may claim a fee lien on the case, but that usually gets worked out between lawyers from the eventual recovery rather than making her pay two full contingency fees.
• For most Oklahoma injury claims, the filing deadline is 2 years from the crash. If a city or other government vehicle was involved, notice deadlines can be much shorter under the Oklahoma Governmental Tort Claims Act.

If the insurer is hiding behind an old MRI, the case usually needs stronger medical causation proof, not surrender.