
When you get hurt in an accident caused by another party’s fault, you might have a personal injury case. In a personal injury claim, you may have the right to recover compensation for the various losses you sustain due to injuries you suffered in an accident. But what happens when you experience new or worsening symptoms of pre-existing injuries or conditions after an accident? Understanding the effect of pre-existing conditions on your personal injury claim can protect your rights to compensation after an accident.
Understanding Pre-Existing Conditions
In a personal injury action, a “pre-existing condition” refers to an injury or chronic medical condition that occurred or developed before the accident giving rise to the personal injury action. Common pre-existing conditions that can play a role in personal injury claims include:
- Bulging or herniated discs
- Prior surgeries
- Chronic neck pain or headaches
- Arthritis
Pre-existing conditions may become an issue in a personal injury claim when insurance companies investigate a claimant’s medical history and find records of prior surgeries, injuries, diagnosed chronic diseases, or musculoskeletal conditions, such as arthritis.
The “Eggshell Skull Rule” and Its Importance
In Missouri, the “eggshell skull” rule, sometimes called the “eggshell plaintiff” rule, makes defendants liable for the full extent of a plaintiff’s injuries and symptoms caused by an accident, even if a plaintiff had a pre-existing condition that made them more susceptible to harm. The rule requires a defendant to “take the plaintiff as they find them.” A plaintiff with a pre-existing condition can rely on the eggshell skull rule to protect their right to recover compensation for any reinjury or aggravation of a pre-existing condition resulting from an accident caused by a defendant’s negligence. For example, suppose a plaintiff in a car accident case had a pre-existing back problem. In that case, the eggshell skull rule allows the plaintiff to recover compensation for an aggravation of their back’s condition or new back injuries.
How Pre-Existing Conditions Play a Role in Your Claim
Pre-existing conditions can become a critical issue in a personal injury case when an insurance company or a defendant’s counsel argues that a plaintiff’s claimed symptoms did not arise from the accident but instead existed before the accident due to the pre-existing condition. As a result, insurers and defendants may offer smaller settlements or deny liability altogether. Plaintiffs with pre-existing conditions can find it challenging to separate old injuries or pre-existing conditions and the symptoms they caused from an aggravation of symptoms caused by an accident. These plaintiffs may require comprehensive and compelling medical evidence to prove that an accident made their pre-existing condition or injury worse.

Proving Aggravation of a Pre-Existing Condition
Proving that an accident aggravated a pre-existing condition may require various evidence, such as:
- Medical records from before the accident that detail the plaintiff’s pre-accident symptoms and the recovery from or management of a pre-existing condition or injury
- Post-accident medical records documenting worsened symptoms
- Expert medical testimony to describe differences in symptoms and limitations, and the medical causation for how the accident worsened the plaintiff’s condition
Working with an Experienced Personal Injury Lawyer
An experienced lawyer can help plaintiffs with pre-existing conditions ensure they receive a full financial recovery for reinjury or worsened symptoms after an accident. Legal counsel can coordinate with medical providers and experts to build a persuasive case. Even if you have a pre-existing condition, you may still have a viable personal injury case. Contact Dreyer & Tinney Law Firm today for a free, no-obligation consultation with a knowledgeable personal injury attorney to learn how pre-existing conditions can affect your injury claim and what rights you have to recover compensation for your harm and losses.
