Pre-existing conditions can be costly for employers

One of the most frequently litigated issues involving workers' compensation claims concerns aggravation of pre-existing employee conditions. Not all employers understand the exposure caused by pre-existing conditions in employees when it comes to workers' compensation insurance. Aggravations of employee pre-existing conditions can result in unexpected and costly claims which greatly increase the cost and expense of an employer's workers' compensation insurance.

Employers can literally find themselves responsible for a three-level back fusion after an employee aggravates pre-existing degenerative disc disease by bending over to pick up a file. The cost associated with such a claim will clearly raise an employer's premiums for their workers' compensation insurance.

The rules concerning aggravations of pre-existing conditions in work related accidents are complex and not understood by many employers. The purpose of this article is to provide an overview of the rules that apply to aggravation of pre-existing conditions in the workers' compensation setting.

Industrial aggravation of pre-existing industrial conditions

Aggravation of a pre-existing industrial condition caused by a new industrial accident is compensable. The typical situation involves an employee who sustained a previous neck or back injury in an industrial accident that causes degenerative disc disease that is then aggravated by a subsequent industrial accident with a different employer.

In these situations, the condition that results from the aggravation of the degenerative disc disease is compensable and the responsibility of the new employer. Grover C. Dils Medical Center v. Menditto, 121 Nev. 278 (2005) is a good example of one of these types of cases. In this case, the claimant, Menditto, was injured in 1997 in a work related automobile accident.

As a result of the accident Menditto was left with cervical spine problems that included protruding discs, spondylosis and anterior spurring in her cervical spine. Over the next four years, Menditto experienced periodic problems involving her cervical spine that required medical treatment.

In 1999, Menditto changed employers. Several years later, in 2001, Menditto filed a new industrial insurance claim contending she aggravated her cervical condition while providing CPR to a patient of her employer. The employer denied the claim contending that her cervical spine condition was simply a reoccurrence of the previous problems caused by the 1997 injury.

The issue presented to the Nevada Supreme Court was whether the new accident constituted an aggravation of her pre-existing condition or was merely a reoccurrence of her previous problems.

In deciding the case, the Nevada Supreme Court defined what constitutes an aggravation in the setting where a pre-existing industrial condition is affected by a subsequent injury. The court concluded that "an aggravation is established when medical evidence demonstrates that a specific subsequent work related incident, amounting to an injury or accident, independently contributed to the final disabling condition." It is not enough that the second or subsequent injury merely caused additional pain to manifest, the subsequent injury must cause the original condition to worsen physically.

Aggravation of a nonindustrial condition by an industrial injury

NRS 616C.175 sets forth the rules that apply to aggravation of a pre-existing nonindustrial condition by an industrial injury. This statute presents a myriad of problems for an employer or insurer dealing with the aggravation of a pre-existing nonindustrial condition.

The typical situation again involves an employee with a pre-existing back or neck condition caused by a previous nonindustrial accident or injury that is then aggravated by a new injury in the workplace.

NRS 616C.175(1) allows workers' compensation coverage if the subsequent industrial accident "aggravates, precipitates or accelerates" the pre-existing nonindustrial condition. The only available defense for an insurer or employer who finds himself in this situation is proving that the subsequent injury was not a "substantial contributing cause" of the resulting condition. "Substantial contributing cause" has never been defined the Nevada Supreme Court but it presumably means something more than simply contributing cause.

Industrial conditions aggravated by a nonindustrial injury

Employers should also be aware that they can be responsible for industrial injuries that are subsequently aggravated by a nonindustrial accident. The typical situation here might involve an employee who has a cervical spine injury as a result of an industrial accident that is then involved in a nonindustrial motor vehicle accident that aggravates the pre-existing industrial condition. NRS 616C.175(2) makes a nonindustrial aggravation, precipitation or acceleration of a pre-existing industrial condition compensable. As was the case with NRS 616C.175(1) the only defense available to an employer or insurer is proving the industrial injury was not a substantial contributing cause of the final condition.


As it is apparent from the previous overview, most aggravations involving industrial injuries are compensable. The only time aggravations are not compensable is when an insurer or employer can prove that the industrial component was not a substantial contributing factor. Moreover, employers and insurers need to be aware that the burden of proving the aggravation was not a substantial contributing cause is on the employer and its insurer.

Employers need to be aware of the exposure posed by an employee's pre-existing conditions because the claims that arise out of these aggravation cases are often quite expensive. Even a relatively innocuous accident in the workplace can lead to a very expensive claim where pre-existing conditions are aggravated.

Additionally, because an employer's access to information concerning pre-existing conditions of its employees is severely limited by HIPAA and the ADA, there is often little an employer can do to protect themselves from these types of claims. However, where an employer has lawfully obtained information concerning pre-existing conditions, it should do everything legally possible to mitigate against subsequent injuries that might aggravate the employee's pre-existing conditions.

Tim Rowe is a partner in the Reno office of McDonald Carano Wilson LLP. He practices mainly in the areas of employment and labor law, as well as construction law and litigation. Learn more about him online at


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