Aggravation of a Pre-Existing Condition

WDC Journal Edition: Spring 2016
By: William R. Wick and Andrew L. Stevens, Nash, Spindler, Grimstad & McCracken LLP

Every personal injury defense lawyer has encountered a case where the plaintiff has had some condition, disease, or ailment that was present or produced symptoms before an accident, and following the accident, it is claimed that the prior condition was worsened. The issue is whether the worsening of the condition was the natural consequence of injuries from the accident. In this situation, the defense lawyer needs to determine how the pre-existing condition can be evaluated to reduce the damages being claimed. The purpose of this Article is to address what a pre-existing condition is, whether it has been aggravated as a result of the accident/incident, and how a preexisting condition is used to reduce the damages.


The legal concept of an aggravation or activation of a pre-existing condition or disease is based on wellestablished law that has been in existence for decades. A jury cannot award damages for any pre-existing disease, condition, ailment, or predisposition except to the extent that it is satisfied that the disease, condition, ailment, or predisposition is aggravated by injuries from the accident.1 Damages may not be awarded if they do not flow from the natural result of injuries received in the accident, nor may damages be awarded for any condition which has resulted, or will result, from the natural progression of the pre-existing disease or ailment as a result of causes unrelated to the accident.2 If the injured party is more susceptible to serious injury by reason of a pre-existing disease, condition, or predisposition to the disease, damages are to be awarded for what is the natural result of the accident even though there is such predisposition or susceptibility.3 Unfortunately, the law gives little guidance as to what constitutes an aggravation or activation, and the assessment turns on the facts of each case. It is the assessment of the factual issues surrounding an aggravation of a pre-existing condition that can be perplexing to the defense lawyer.

When there is a pre-existing condition, the question is whether the trauma of the accident caused a worsening of the condition, or caused a condition that was asymptomatic prior to the accident to become symptomatic following the trauma of the accident. The defense seeks to show through lay and expert testimony that no damages can be awarded for a pre-existing condition unless it is brought into activity as a natural result of the injuries received in the accident.4 The Wisconsin Supreme Court has determined that plaintiff's disability, before and after the accident, which affects the same parts of the body and same bodily functions before and after the accident, presents a question for the jury.5

Degenerative disease or arthritis of the spine and joints is the most common condition that raises the issue of aggravation of a pre-existing condition. In these situations, there is generally a degenerative arthritic change that is present prior to the accident which is alleged to have been aggravated or worsened by the trauma of the accident. This aggravation presents in the form of increased symptoms, disability, and/or the need for additional treatment that was unnecessary prior to the traumatic event. The additional treatment can include medications, physical therapy, injections, radiofrequency ablations, joint replacements, or vertebral fusions, all of which, in the view of the defense, would still have been necessary absent the trauma from the accident.

Causation Issues

The rationale for causation frequently employed by the plaintiff is that the plaintiff did not have any complaints before the accident, had them following the accident, and therefore the accident must have caused them or made them worse. This is known as "post hoc ergo propter hoc," which is Latin for "after this, therefore because of this." This fallacy assumes that if one event occurs after another, then the first event must have caused the second event. It does not necessarily follow that if the plaintiff did not have complaints for a period of time before the accident, and symptoms were reported following it, that the accident was the cause. However, defense counsel needs to offer proof that this is the case.

Briefly summarized, when a person has a preexisting condition or injury that has already caused or is causing harm to some degree, the person causing the harm is only liable for any enhancement of the harm caused by the negligent or intentional conduct.6 The injury or damage may far exceed what is anticipated from the nature of the trauma. In addition, Wisconsin law has accepted the Restatement of Torts view that "you take the plaintiff as you find him/her," and has adopted the "eggshell skull" rule, which is that unusual susceptibility to trauma does not relieve the defendant of his or her responsibility for the outcome.

The Role of Expert Testimony

Whether a pre-existing condition is aggravated or a latent condition activated is usually the subject of conflicting expert testimony. Conflicting expert opinions present a question for the jury. Peters v. Zimmerman,7 a 1957 Wisconsin Supreme Court case, dealt with a cause question involving a congenital pre-existing condition that may have played a factor in the damages. A minor plaintiff was riding on a tractor that was involved in combining, a rut in the field was negligently struck, the minor was thrown and his crotch and the rear of his right thigh made contact with a crossbar. The injury was not noted immediately. The minor began to limp and complain of pain two months after the accident. Treatment was initiated for probable Perthes disease of the right hip. Perthes disease is a rare childhood condition that affects the hip. It likely occurs when the blood supply to the rounded head of the femur is temporarily disrupted. There was a difference of expert opinion in Peters as to whether Perthes disease could be caused by trauma. The court held that where there is a difference of opinion between qualified experts, the jury needs to resolve the issue.

The effect of conflicting expert opinions and the arguments that can be made from preexisting conditions are also illustrated in Anderson v. Milwaukee Insurance, a 1991 Wisconsin Court of Appeals case.8 In Anderson, the plaintiff had a latent congenital inguinal hernia. An inguinal hernia is a weakness in the abdominal wall that exists from birth. The hernia can become apparent when there is abdominal pressure on a weak abdominal wall that allows the contents to bulge into the abdomen. When the hernia is diagnosed, surgery is the treatment of choice. Plaintiff alleged that an automobile accident caused the latent hernia to become apparent and require treatment. After the accident, the plaintiff was treated and released. Eighteen days after the accident, the plaintiff reported continuing pain in the groin area. The expert testimony was conflicting, but the experts agreed that the hernia was congenital and would not become apparent until there was some pressure in the abdomen. The experts disagreed as to what caused the hernia to become apparent and whether it would have become apparent absent the trauma of the accident. The trial court found that the accident made the latent hernia apparent but concluded that the repair of the hernia was not compensable because the hernia was the result of the natural progression of the pre-existing condition and would still have occurred absent the accident.

The court of appeals rejected the defense's argument that there could be no recovery because the pre-existing condition was treated sooner rather than later. The court of appeals said that Wisconsin law does not support the proposition that when the injuries from an accident are the same as the injuries that may inevitably occur due to a preexisting condition, the injuries from the accident are completely un-compensable, but the court said that "such a situation may reduce the amount of damages."9

The Anderson court relied on Fantin v. Mahnke10 in support of its decision. In Fantin, the plaintiff was already "on the road" to a hip replacement before the accident occurred. The court held that although the accident aggravated a pre-existing condition, there was sufficient evidence that the pain would have been the same without the accident and therefore damages for future pain and suffering were properly denied by the jury. The holding in Anderson was that, while a plaintiff may inevitably suffer from a pre-existing condition unrelated to the accident, the defendant is still liable for damages that are a natural consequence of the accident. Where the plaintiff's increased injuries are the natural consequence of the accident, the defendant's argument is relevant only to determine the amount of damages. Thus, it is difficult to determine where the court draws the line on damages that are the natural consequence of the accident and those that are the result of the preexisting condition.

In Fantin, the plaintiff had hip and back problems that predated the accident by at least four years. The expert testimony was that the plaintiff had pre-existing arthritis and that a hip replacement was necessary because of it. The expert testimony conflicted. One expert concluded that the accident was the triggering mechanism for the pain. The other expert countered that hip surgery was inevitable with or without the accident. The court held that although there was testimony that the accident aggravated pre-existing conditions, because there was also testimony that the pain and disability would have been the same without the accident, a jury finding of no damages for future pain and suffering was justified. The conclusion one can reach from Anderson and Fantin is that if a latent condition is activated or aggravated, the fact that the same treatment, pain, and disability would have occurred at some point in the future does not prevent recovery, but such evidence may be taken into consideration by the jury in considering the damage award.

Strategies for Defending Cases Involving Pre- Existing Conditions

Defending damage claims involving pre-existing conditions involves issues that are more medical than legal. The defense position is that the plaintiff had the condition before the accident, the treatment was likely to have been necessary absent the trauma of the accident, and the increased symptoms were simply caused by the natural course of the disease process and would have occurred absent the trauma of the accident. This often requires resolving a conflict between subjective complaints and objective medical information. This is a conflict between signs and symptoms. A sign is an indication of a medical condition that can be objectively detected. A symptom is a manifestation of a condition that is apparent to the patient. Symptoms are subjective explanations. Signs are objective findings. The plaintiff will rely on the subjective assessment of the plaintiff's symptoms as being worse after the accident. Defendants will point to the absence of signs caused by the accident to explain the symptoms. The problem is further complicated by the fact that a condition such as arthritis may be present and detectable but still be asymptomatic. Thus, the defense view will be that for a preexisting condition to be aggravated there must be an identifiable explanation for the symptoms that is anatomically consistent with the type and nature of the trauma sustained in the accident.

Even if the plaintiff's symptoms have worsened after the accident, the defense position is that the plaintiff's pre-accident condition has not progressed beyond its normal course. The pathophysiology of arthritis or degenerative changes is progressive. The defense claim is that the natural course of the condition would have been to progress to the point of needing treatment absent the trauma of the accident. The plaintiff's position will be that while the condition is progressive, the rate of progression is unpredictable and indeterminate and therefore the defense contention is invalid.

In assessing whether a pre-existing condition has been aggravated beyond its normal progression, a thorough knowledge of the plaintiff's medical history and a detailed deposition are required. Consultation with a medical or surgical specialist with experience in evaluating and treating the preexisting condition is essential. Determining whether there has been an aggravation or activation and the extent of it requires a comparison of signs and symptoms that existed before and after the accident. Consideration may be given to the following:

  • Symptoms. Although symptoms are subjective, establishing the pre-accident baseline and comparing it to post-accident complaints may show there has been no aggravation. Factors to consider are:
    1. Location: This requires an assessment of whether the pain pre- and post-accident is in the same location anatomically—i.e., involves the same vertebral level, the same muscle, etc.
    2. Frequency: A change in frequency of symptoms may be significant and includes whether the symptoms are constant or intermittent, and if intermittent, how the duration of intermittent pain has changed.
    3. Intensity: The intensity of the pain is generally rated on a 0 to 10 scale with 0 being no pain and 10 being the worst pain imaginable. Records and/or testimony can provide the basis for a comparison using this method of assessment.
    4. Onset: The length of time between the accident and the first report of symptoms may suggest that the pre-existing condition was not aggravated.
    5. Type: The similarity or change in the description of pain using terms such as aching, burning, shooting, dull, sharp, etc. may suggest whether there has been an aggravation.
    6. Nonspecific complaints: Subjective complaints are non-specific. The presence of pain in and of itself is not specific as to any medical cause. Therefore, the defense to a claim of aggravation of pre-existing injury is best tied to the absence of an explainable physiological cause, i.e., some abnormality that is causing the pain or is considered the pain generator. Without an etiology or identifiable pain generator, the complaint of pain is of unknown origin and not the result of an aggravation of a pre-existing condition.
  • Diagnosis and treatment. With respect to this category, consider the following factors:
    1. Prior diagnosis and treatment: A preaccident diagnosis of a progressive condition such as degenerative joint disease or arthritis for which there was ongoing pre-accident treatment may be used to suggest there was no aggravation.
    2. Future treatment: The medical records may reflect that the patient will require future treatment for the pre-accident condition. This suggested treatment may be in the form of injections, radiofrequency ablations, or surgery, including a future joint replacement or vertebral fusion.
    3. Temporal relationship: The proximity of diagnosis and treatment to the accident may be a factor. Continuing regular treatment shortly before the accident may suggest an ongoing or progressive problem. The greater the length of time between the last treatment and the accident, the more likely it is that the trauma accelerated the condition.
    4. The effect of prior treatment: A person with prior back complaints treated by discectomy or fusion may be susceptible to the need for future treatment at the levels above and below without intervening trauma, or abdominal surgery may weaken an area making it more susceptible to future injury.
    5. The nature of the post-accident treatment: The type of post-accident treatment may reflect a pre-accident condition that was not aggravated by the trauma of the accident. Opinions may be obtained that a multi-level spinal fusion is unrelated to a single traumatic event. The need for a carpal tunnel surgery is generally considered to be the result of ongoing repetitive activity over a significant period of time. The type of condition and the form of treatment may suggest a mechanism of injury that is unrelated to trauma from the accident.
    6. Gaps in treatment: Intervals in continuity of treatment are assessed from two perspectives: (1) the time interval between the accident and the onset of the treatment; and (2) the length of the interval between treatments that were received after the accident. The longer the lapse of time between the accident and the first report of a symptom that is claimed to be related to the accident, the better the argument that the trauma of the accident was not the cause. A lapse in post-accident treatment may suggest recovery. Many conditions caused by trauma are self-limiting. A preexisting condition may be aggravated for a period of time and then the symptoms return to baseline. An initial report of pain followed by a lengthy hiatus of treatment suggests that the injury was self-limiting. If treatment is resumed at a later date, it can be claimed that the treatment is unrelated to the accident. A timeline and/or calendar of medical contacts showing significant gaps in treatment may be helpful to show that any claimed aggravation was temporary.
  • The physical examination: A physical examination that is consistent with pre-accident findings can be said to be objective evidence of lack of aggravation of a pre-existing condition. The physical findings may also indicate there was no aggravation; for example, a nerve injury should be consistent with deficits in the anatomical distribution of the nerve. Complaints that do not follow an anatomic distribution reflect lack of physiological cause.
  • Permanency: A prior accident with the same type of trauma and a finding of permanency may be helpful to show there was no aggravation. Prior trauma that resulted in an injury with permanent residuals may be used to suggest a lack of aggravation, if the permanent residuals are the same. For the person that is totally disabled, even if it is from a condition unrelated to the accident, it is difficult to envision a disability greater than total. Where there is a prior surgery such as a spinal fusion, there is always some degree of permanency. Permanent restrictions on activity pre-trauma may be used to assess the extent of the aggravation post-trauma.
  • Imaging studies and diagnostic tests: The assessment of an aggravation of a pre-existing condition may be aided by diagnostic studies. Changes in degenerative disease can be assessed with imaging studies such as x-rays, CT scans, and MRIs. While imaging studies are considered to be objective evidence, these studies are subject to interpretation. There is a subjective component to the objective data. This is particularly true in assessing whether there has been aggravation of a disease or condition beyond its normal progression. Defendants should seek the opinion of an expert that the imaging studies pre-accident are unchanged from those postaccident or, if there are changes evident, that the changes do not exceed the normal progression. What constitutes normal progression is subject to interpretation. Reports in the medical records or opinions from consultants that degenerative joint disease is unchanged, that the joint space is no different, or that the disc bulge or herniation is the same, support the position that there has been no aggravation. Frequently, when a nerve injury is claimed, electromyogram and nerve conduction studies are done. These too involve interpretation by the physician giving the test. Consistent results before and after the accident or an equivocal interpretation may be helpful. Diagnostic nerve blocks are often used to determine if nerve root compression is caused by a disk injury. The nature of these tests needs to be assessed and may be helpful to show that there is no aggravation of the pre-existing condition.
  • Type of trauma: The nature of the trauma that is alleged to have caused the aggravation must be assessed. Low velocity impacts may not produce sufficient forces to cause an aggravation of the pre-existing condition. How the trauma was applied should also be considered. Attributing wrist and upper extremity problems to grasping the wheel or bracing for the accident may not result in forces that could produce the injuries claimed. Thus, it is important to determine the movement of the plaintiff's body after impact, whether there was contact with the interior of the vehicle, whether the seatbelt and shoulder harness held them in place, and the effect of the airbag. The defense may rely on an opinion from an examining physician that the nature of the trauma is not likely to cause the injuries complained of based upon the background, training, and experience of the physician, and the mechanism of the injury. For some injuries, a biomechanical assessment may be used to show that the force threshold for causing injury was not reached.


The effect of a pre-existing condition on the evaluation of a case for settlement, for mediation, and for evaluation of the award a jury may ultimately make is perplexing. Even the "objective" assessments have a subjective component. Determining that a medical condition or disease is "aggravated beyond its normal progression" is illdefined. The assessments are based on the opinions of the medical experts on one hand, and on the subjective complaints of the plaintiff and those close to him or her on the other. Thus, the effect of a pre-existing condition on the valuation of damages depends upon the credibility of the witnesses. The credibility of the plaintiff's explanation of the trauma and its effect on the pre-existing condition is likely to have significant weight. The portrayal of the plaintiff's treating physicians as objective and unbiased in contrast to the defense experts as biased and hired guns will certainly come into play. The ultimate benefit of the pre-existing condition defense may be to attack the credibility of a plaintiff who is seeking unreasonable compensation, overstating the post-accident related complaints, and denying or significantly downplaying preexisting conditions that were definitely operating and having an effect.

William R. Wick, is a defense lawyer who concentrates his practice in the areas of medical malpractice and general personal injury litigation. He received his B.S. in 1970 from Carroll College, his M.P.A. in 1972 from the University of Southern California, and his J.D. in 1974 from Marquette University Law School. Mr. Wick was certified by the American Board of Trial Advocacy as a Civil Trial Specialist. He is a member of the State Bar of Wisconsin and a past chair of the Litigation Section. He has also been President of the Civil Trial Counsel of Wisconsin now known as the Wisconsin Defense Counsel. Mr. Wick is a fellow of the American College of Trial Lawyers. He has also been President of the Wisconsin Chapter of the American Board of Trial Advocates (ABOTA). He has also been selected to be included in Best Lawyers in America for the last nine years. Mr. Wick is a frequent lecturer on topics involving civil litigation.

Andrew Stevens is an associate at Nash, Spindler, Grimstad and McCracken, LLP. Andrew joined the firm in 2014 and practices in the areas of litigation and insurance defense. Prior to joining the firm, Andrew worked as a police officer for 11 years with the Wayne County Sheriff's Department in Detroit, Michigan and served as the judicial law clerk for Judge Amy Hathaway at Wayne County Circuit Court. Andrew is licensed to practice law in Wisconsin and Michigan.

1 See Wis. JI-Civil 1715 – Aggravation of Pre-Existing Injury.
2 Id.
3 See Wis. JI-Civil 1720 – Aggravation or Activation of a Latent Disease or Condition.
4 Kablitz v. Hoeft, 25 Wis. 2d 518, 525, 131 N.W.2d 346 (1964).
5 See Leusink v. O'Donnell, 255 Wis. 2d 627, 631, 39 N.W.2d 675 (1949).
6 Anderson v. Milwaukee Ins., 161 Wis. 2d 766, 769, 468 N.W.2d 766 (Ct. App. 1991).
7 275 Wis. 164, 170, 81 N.W.2d 756 (1957).
8 Anderson, 161 Wis. 2d 766.
9 Id. at 770.
10 113 Wis. 2d 92, 334 N.W.2d 564 (Ct. App. 1983).