On October 17, 2018, the Pennsylvania Supreme Court overturned a Superior Court ruling involving an exception to the Pennsylvania statute of limitations for medical malpractice actions. The discovery rule allows a patient to bring a claim after the statute has passed, if they were unaware of their injury until after it occurred. The Court revived a plaintiff’s case under the discovery rule, allowing the patient’s claim to go forward. The Supreme Court’s decision effectively places less responsibility on a patient to actively participate in their medical care.

Under the Pennsylvania statute of limitations, a plaintiff must bring a medical negligence claim within two years after an injury occurs. There is an exception, deemed the “discovery rule,” which allows extra time to file the claim if the plaintiff was unaware of the injury until after two years had passed. Under the discovery rule, the statute of limitations starts to run at the time the plaintiff either knew or could have reasonably ascertained that they had an injury caused by negligence. The law requires that the patient be “reasonably diligent” in finding out about their injury.

In Nikolaou v. Martin[1], plaintiff sued various medical providers relying on the discovery rule, claiming that, although Mrs. Nikolaou contracted Lyme Disease in 2001, she was unaware of the diagnosis until 2010 because her providers failed to diagnose it. Following a tick bite in 2001, Mrs. Nikolaou was treated by several providers, each of whom performed blood tests for Lyme Disease. All the tests were negative. In 2006, she had an MRI which revealed inflammation consistent with Multiple sclerosis (MS) or Lyme Disease. Based on her symptoms and negative Lyme Disease tests, she was treated for MS. When her symptoms did not improve, Mrs. Nikolaou sought treatment from Nurse Practitioner, Rita Rhoads, whom she had heard was responsible for treating Lyme Disease patients formerly incorrectly diagnosed with MS.

When she first saw Nurse Rhoads on July 29, 2009, Nurse Rhoads told Mrs. Nikolaou that she believed she had Lyme Disease, and began treating her with antibiotics. She also recommended a diagnostic test (the “IGeneX test”) to further confirm the diagnosis. However, Mrs. Nikolaou refused the IGeneX test until February 1, 2010, seven months later. The record indicates that Mrs. Nikolaou refused the test because she did not have health insurance and did not want to pay out of pocket. Nurse Rhoads advised Mrs. Nikolaou on February 13, 2010 that the results were positive. Plaintiff filed a medical malpractice claim on February 10, 2012.

As defendants discovered, following the IGeneX test, Mrs. Nikolaou posted on her Facebook page that she had suspected for years that she had Lyme Disease, but her doctors had ignored her. The trial court granted defendants’ motion for summary judgment, refusing to apply the discovery rule to plaintiff’s case because “reasonable minds could not differ” that Mrs. Nikolaou suspected or had reason to suspect that she had Lyme Disease as early as July 2009. The Superior Court affirmed, reasoning that Mrs. Nikolaou was put on notice when the MRI was suggestive of Lyme Disease, Nurse Rhoads told her she probably had Lyme’s and started treatment which improved her symptoms, and she declined to take the IGenX test for several months to confirm the diagnosis.

The Pennsylvania Supreme Court heard argument on plaintiff’s appeal on May 17, 2018. Plaintiff argued that the case was improperly dismissed, because the issue of whether Mrs. Nicolaou knew or should have known about her Lyme Disease should be submitted to a jury. Plaintiff first argued that the defendants did not meet their burden to prove that no juror could find that plaintiff had not been reasonably diligent in discovering the alleged negligence. Next, they argued that the reasonable person standard under the discovery rule is subjective and depends on what a reasonable person in the plaintiff’s particular circumstance would do. They also argued that a patient’s financial capability should be considered in the determination.

Defendants rebutted each of plaintiff’s claims, stating that it was plaintiff’s burden to prove the discovery rule applied to her, and that the reasonable person standard is an objective test, to which financial considerations do not apply. Defendants also noted that the rule did not require knowledge of negligence—just that a cause of action be “ascertainable.”  Defendants thus argued that the statute of limitations did not start to run only upon a final diagnosis.

Justice Baer agreed with defendants’ first two arguments. He noted that the discovery rule is narrow, and plaintiff has the burden to prove that the discovery rule applies. He also agreed with defendants that the reasonable person standard is an objective test. He stated that “the question is not what the plaintiff actually knew of the injury or its cause, but what he might have known by exercising the diligence required by law.” He went on to note however, that this objective test is “sufficiently flexible” to consider individual circumstances. He therefore reasoned that financial considerations is a permissible factor in deciding discovery rule issues.

Justice Baer ultimately found for the plaintiff. In rejecting the Superior Court’s decision, he stated that the Court had improperly concluded that Mrs. Nikolaou knew or should have known of her diagnosis by July 2009. Justice Baer held that, while the facts may establish that Mrs. Nikolaou knew or reasonably should have known she suffered an injury due to the defendants’ negligence, a jury could also find the opposite. The Superior Court inappropriately undertook a fact-resolution function, which is reserved for the jury.  Further, it was inappropriate for the Superior Court to decide whether Mrs. Nikolaou should have taken the IGenX test in July 2009. He stated that this factor should also be determined by jury. He concluded by citing a Supreme Court case where the court held that the discovery rule imposes “a reasonable diligence requirement, as opposed to an all-vigilant one.”[2]


[1] 44 MAP 2017 (Pa. Oct. 17, 2018)

[2] Wilson v. El-Daief, 964 A.2d 354 (Pa. 2009).