Last updated · By Mustafa Bilgic
Three situations that are often confused
| Situation | Example | Damages focus |
|---|---|---|
| New, separate injury | A person with old knee arthritis suffers a crash-caused wrist fracture. | The new wrist injury and its resulting losses. |
| Aggravation | Stable lumbar symptoms become materially worse after a collision and require new treatment. | The additional severity, duration, care, restriction and loss caused by the collision. |
| Unchanged natural progression | Symptoms continue on the same course with no supported accident-related change. | No recovery for loss the accident did not cause. |
Real cases can include all three. A crash may cause a new strain, temporarily aggravate degenerative disease and leave another condition unchanged. The medical opinion should address each rather than use the vague phrase “pre-existing problem.”
Eggshell plaintiff versus aggravation
Under the general eggshell-plaintiff principle, a negligent actor takes the injured person as found. If the same impact causes unusually serious harm because the claimant has fragile bones or another susceptibility, the harm is not automatically cut down to what an average healthy person would have experienced. Federal jury materials describe responsibility for injury even when a prior condition made the plaintiff more susceptible, provided the defendant's conduct was a causal factor.
Aggravation asks a related but distinct question: what extra harm did the accident add to an active condition? A claimant should not receive the value of limitations that would have existed anyway, but should not be denied the measurable worsening caused by the defendant. The exact instruction and burden vary by jurisdiction.
Build a before-and-after medical baseline
The most persuasive file does not hide the past. It shows the past accurately and then demonstrates the change.
| Before the event | After the event | Why the comparison matters |
|---|---|---|
| Visit frequency, medication and pain reports | New visits, stronger medication or injections | Shows a change in treatment intensity. |
| Work status and restrictions | Missed shifts, reduced hours or new restrictions | Measures functional and wage impact. |
| Prior imaging and examinations | New imaging and objective findings | May distinguish chronic findings from acute change. |
| Activities performed independently | Tasks no longer possible or requiring help | Documents loss of normal function. |
| Stable or intermittent symptom pattern | Different severity, frequency or duration | Defines the incremental harm. |
Give the evaluating clinician accurate prior records and a specific history. Ask the clinician to address diagnosis, causation, whether the condition was symptomatic before, the expected natural course, the degree and expected duration of aggravation, and any new treatment or restriction. See medical evidence for an injury claim.
Why honesty usually strengthens the claim
Insurers can obtain authorized records, claims histories, prior imaging and discovery responses. An incorrect denial of any previous back pain can become a credibility issue even if the collision genuinely caused a major worsening. A precise statement is stronger: “I had two short episodes treated conservatively in 2023, had no care or restrictions for 18 months before this crash, and after the crash required weekly treatment and could not lift at work.”
- List prior accidents, diagnoses, surgery, treatment and affected body parts for counsel.
- Do not guess dates; verify them.
- Distinguish no symptoms, occasional symptoms and active symptoms.
- Explain gaps in both prior and current treatment.
- Correct an inaccurate intake history promptly and transparently.
How aggravation damages are valued
Start with the loss caused by the post-event change: additional medical cost, lost wages, care needs, pain, limitations and future risk. Suppose a claimant had mild monthly back discomfort but no wage loss or active care. After a crash, symptoms become daily for eight months, require injections and physical therapy, and cause six weeks off work. The claim is not automatically for every lifetime effect of degeneration; it focuses on the eight-month aggravation, additional treatment, wage loss and any supported permanent acceleration or residual worsening.
Use the back injury calculator, lost wages calculator and pain-and-suffering calculator as rough range tools. A medical opinion separating baseline and change is more important than any multiplier.
Common insurer arguments and useful responses
- “It is all degeneration.” Compare symptoms, treatment and function before and after; obtain a causation opinion that addresses the imaging rather than ignoring it.
- “The same body part was treated before.” Show duration of stability, different diagnosis or materially increased care and restriction.
- “There was a treatment gap.” Explain access, referral, cost or attempted self-management with records where possible.
- “The impact was minor.” Vehicle damage alone does not diagnose a person; use crash facts and medical evidence without overstating either.
- “The condition would have worsened anyway.” Ask the expert to distinguish natural progression from accident-caused acceleration and state the basis.
Present that comparison cleanly in the settlement demand.
Frequently asked questions
Can I claim with a pre-existing condition?
Yes. A prior condition does not automatically bar recovery. Prove that the defendant caused a new injury, aggravated the condition or made an existing vulnerability produce greater harm.
What is the eggshell-plaintiff rule?
The general principle is that a negligent defendant takes the claimant as found and may be responsible for greater caused harm because that person was unusually susceptible. Causation is still required.
Do I have to disclose old treatment?
Relevant prior history is ordinarily discoverable and should be addressed accurately. Document the medical and functional baseline, then explain the measurable post-event change.
How are damages calculated?
Damages generally focus on additional harm: increased symptoms, new treatment, longer disability, new restrictions, extra medical cost and income loss. Local eggshell and apportionment rules affect the final analysis.
Legal reference
A federal district court's eggshell-plaintiff jury instruction (PDF) illustrates the general causation and susceptibility principle. It is not the instruction for every state or case.