Risk Management

Time Sensitive Conditions and Errors in Diagnosis

Paul Weber, JD, OMIC Vice President of Risk Management/Legal

Digest, Spring 2013

Claims related to error in diagnosis continue to challenge OMIC and other medical professional liability carriers. “Diagnostic error” is broadly defined as a diagnosis that is missed, incorrect, or delayed as detected by a subsequent definitive test or finding. Recently, researchers at Johns Hopkins University reviewed 25 years of malpractice claims reported to the National Practitioner Data Bank between 1986 and 2010. [1] Their research revealed that “… among malpractice claims, diagnostic errors are the most frequent, most severe, and most costly of all medical mistakes.” Although diagnostic error cases account for only 13% of OMIC closed claims, they are the most costly, resulting in over one-third of the indemnity paid to plaintiffs.

Managing the risk related to diagnostic error claims involves analyzing both system-related factors (patient-to-physician communication and communication among physician and other health care providers) and cognitive factors (physician did not gather relevant data optimally or failed to synthesize data correctly).

Time is of the essence

OMIC has noticed a subset of “time sensitive” diagnostic error cases in which there was a relatively brief period of time between when the patient was examined and when medical/surgical intervention or referral needed to occur. Many of these OMIC cases included both system-related and cognitive factors that contributed to the error in diagnosis. OMIC closed six such cases in 2012 (ROP, trauma, stroke, aggressive glaucoma, retinal detachment, and endophthalmitis), which accounted for 40% of the $10 million indemnity paid out last year. With the exception of the ROP case, there was an average of only five days between the first patient contact and the correct diagnosis, indicating that clinicians had a brief window in which to make a correct diagnosis before the patient suffered significant problems. A stroke case that settled for $500,000 is a particularly good example of a time sensitive case in which both system-related factors and cognitive factors combined to lead to a diagnostic error and large indemnity payment.

An accident waiting to happen

On March 14, a 53-year-old male patient presented to the insured with complaints of seven or eight episodes of right eye visual acuity loss over the past month. He was not an established patient, and it was unclear whether he was referred by his primary care provider (PCP) as the insured believed, or self-referred as the patient later claimed. The patient reported episodes when his vision became very gray except for a small area at the top. These episodes usually occurred when bending over or straining, lasted four to five minutes, and were sometimes followed by a slight pain in the right eye. The eye exam was essentially normal except for a posterior, subcapsular, polar senile cataract. The patient was noted to be in good general health and oriented to person, place, and time. Since these episodes occurred when the patient bent his neck or strained, the insured believed these actions caused plaques to break off and float to the ophthalmic artery or caused vascular compression. The insured’s diagnosis was transient arterial occlusion of the retina. He instructed the patient to be seen by the referring PCP within two weeks for a workup of transient ischemic attacks (TIA). The patient was told that the PCP would most likely order a carotid ultrasound, and he was advised to “phone immediately for increased pain, increased redness, or decreased vision.” Customarily, the insured’s office would have made the patient’s appointment with the PCP but did not in this case for reasons that are unclear.

The insured sent a letter to the PCP regarding his examination and discharge instructions. The letter stated that the patient had been having amaurosis fugax episodes in the right eye for a few weeks. The PCP later testified that she never received the insured’s letter and, unbeknownst to the insured, the patient had not been seen by this PCP for over four years and was not considered a “current patient.”

A few days after being seen by the insured, the patient had another episode of transient vision loss but did not seek medical attention. One week later, on March 21, the patient collapsed at work. He was taken by ambulance to a large medical center presenting with slurred speech and left-sided weakness. A CT scan of the brain taken in the ER showed a hyper-dense clot in the right cerebral artery, consistent with acute occlusion. There was no evidence of hemorrhage. A bilateral carotid Doppler performed on the same day showed near total occlusion of the right internal carotid artery and 50–60% lesion on the left internal carotid artery. The patient had a cerebral vascular accident (CVA) due to a cerebral clot.

After discharge and rehabilitation, the patient had minor left upper extremity dexterity problems and transient issues with executive cognitive functioning. He filed a lawsuit against the insured, alleging that given the number of episodes of amaurosis fugax, the insured should have referred him for an appropriate workup by a neurologist within 24 to 48 hours. The venue of the lawsuit was “plaintiff friendly” and the jury verdict range was estimated between $1 million and $2.5 million.

OMIC retained three different neuro-ophthalmologists to review the case. One of these experts wanted to be supportive but felt the history taken was a “little lean.” He also stated that “common sense” and “intuition” should have given the insured a sense of urgency regarding the seven or eight events in a one month period. Another expert stated that the insured too quickly ruled out “transient visual obscuration” from the differential diagnosis and that the insured’s theory of “plaque breaking off” and flowing through the carotid artery was a powerful argument for immediate care. The third neuro-ophthalmologist, who testified for the insured, stated that a work-up for amaurosis fugax is not “urgent” or “emergent” when several episodes have occurred over the course of a month or so and are not accompanied by other, more worrisome symptoms. All three experts agreed that had a Doppler ultrasound been ordered quickly, it would have identified the source of the clot at the base of the carotid artery and a surgical correction would have prevented the CVA.

Since the insured was a general ophthalmologist, OMIC also had a general ophthalmologist review the case. She opined that there should have been an urgent (same day) referral to the PCP. She felt strongly that if the PCP could not or would not see the patient, the patient should have been referred to the ER for emergent evaluation, including a neurology consult.

A non-binding hearing was conducted and found that the insured breached the standard of care by not referring the patient to the PCP on a more urgent basis within 24 to 48 hours. However, the hearing panel determined that the plaintiff was more at fault than the insured for not acting sooner to take care of himself, i.e., not making the appointment with the PCP. Also, the panel felt that the patient could have had the stroke at any time, including during the insured’s examination or immediately after he left his office, and that it was speculative whether the stroke could have been avoided. Given the hearing panel’s decision on the standard of care, the consensus of defense counsel, OMIC’s claims department, and the insured was that it was too risky to go to trial and the matter was settled with a $500,000 indemnity payment to the plaintiff.

System-related factors

A “perfect storm” of missed opportunities contributed to the delay in diagnosing the cerebral clot. First, the insured and his staff had different understandings about whether the patient was referred by his PCP or self-referred. The insured erroneously believed that the PCP had referred the patient and, therefore, knew about the episodes of vision loss. The insured also said it was highly unusual for his staff to field a call of vision loss and not make an appointment on a more urgent basis, although there were no written office policies or telephone guidelines for handling appointments.

Had the insured checked the OMIC website, he would have found comprehensive written telephone policies and procedures that would have provided his staff with a checklist to help them gather the necessary information from the patient and determine the appropriate appointment category: emergent, urgent, or routine. Checklists become especially important with time sensitive conditions such as neuro-ophthalmic problems. To this insured’s credit, he made several changes in his appointment practice protocol as a result of this case, including a daily review of all referrals and accompanying paperwork to verify that appointments are scheduled appropriately.

Another system-related issue that frequently impacts time-sensitive conditions is poor communication between provider and patient regarding the nature and urgency of the patient’s condition. The patient in this case claimed not to understand the importance of the follow-up appointment with the PCP and testified that he thought someone would call him with a date for the carotid ultrasound. Even though the hearing panel believed the insured had communicated the urgency of the problem and the patient was primarily responsible for not following up more quickly with his PCP, the case would have been more defensible had the office actually made the referral appointment for the patient. If they had, they would have learned that the PCP was not currently treating the patient, which might have led the ophthalmologist to treat this patient as more high risk. At a minimum, the practice should have given the patient a form specifically indicating the urgency of the appointment.

As noted here and in the Closed Claim Study regarding pseudotumor cerebri, some patients are not fully engaged in the process of their own care. Many ophthalmic practices do a good job of educating and empowering their patients on certain procedures and risks. The American Academy of Ophthalmology patient education brochure “Floaters and Flashes—A Closer Look” is an example of ophthalmologists educating patients to seek timely follow-up care and medical advice and to become active participants in their own care and diagnostic process.

Cognitive factors

In the past few years, the research and literature on diagnostic error have grown significantly. In 2007, Boston hematologist-oncologist Jerome Groopman vividly described in his bestseller “How Doctors Think” how thought processes underlie many diagnostic errors. Cognitive psychologists and researchers who have analyzed diagnostic error believe physicians use a “dual process” to arrive at a diagnosis using both “System 1,” an intuitive/subconscious process, and “System 2,” a systematic, analytical process. When using System 1, physicians employ mental shortcuts (heuristics) to reach decisions that are right the majority of the time. The insured in the stroke case later acknowledged several cognitive processing errors, biases, and limitations linked to System 1 shortcuts.

First, the patient’s general good health alleviated concern about the amaurosis fugax being urgent or emergent. The insured saw the patient in the context of an otherwise healthy 53-year-old man. This is an example of “context error,” which can occur when the diagnosing physician is biased by patient history, previous diagnosis, or other factors and thus formulates the case in the wrong context.

Second, the fact that the patient’s symptoms occurred mostly when he was bending over caused the insured to give too much weight to a diagnosis of transient arterial occlusion. The neuro-ophthalmology experts pointed out that the insured’s own patient history was incomplete and he did not develop a differential diagnosis, too quickly coming to the conclusion of transient arterial occlusion. This is an example of “premature closure.” The insured narrowed his choice of diagnostic possibilities (i.e., hypotheses) too early in the diagnostic process, such that the correct diagnosis was minimized or not considered.

Finally, the insured himself felt the biggest lesson he had learned was to consider the most serious potential diagnosis and let it drive the plan. To improve his understanding of neuro-ophthalmic risk, the insured participated in several CME courses related to transient visual loss and diagnosis and management of neuro-ophthalmic emergencies.

In order to reduce System 1 (intuitive) cognitive processing errors and related biases, some experts suggest a checklist. A copy of several sample checklists can be found at https://orlando.isabelhealthcare.com/pdf/EducationStrategiesToReduce DiagnosticError.pdf.

Checklists are simply a reminder to perform a conscious, reflective review to optimize clinical decision making and provide corrective oversight to the automatic processing that underlies diagnostic errors such as the one demonstrated in the stroke case.

Error in diagnosis is a challenge facing all of medicine. Multiple factors, system-related and cognitive, are involved. OMIC believes that only with sustained research to better understand these multiple factors will interventions be developed to reduce errors that cause injury to patients and result in claims against physicians and other health care providers.

1. Saber, Tehrani AS, Lee HW, et al. “Quality and Safety in Health Care.” First published online April 22, 2013 as doi: 10.1136/bmjqs-2012-001550.

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