Risk Management

Differential Diagnosis: Develop and Disclose It

Anne M. Menke, RN, PhD, OMIC Risk Manager

Digest, Winter 2010

Failure to diagnose is a frequent allegation in medical malpractice lawsuits. OMIC claims analysis and peer-reviewed studies point to some ways to reduce this obstacle to safe, quality patient care.

Q  Are there common problems that surface in “failure to diagnose” cases?

A  Yes, but they are not what the court system would lead us to believe. Alleging that a patient suffered harm due to a physician’s negligence implies that the diagnosis was missed because of that particular doctor’s shortcomings. In fact, inadequate knowledge or skill was the cause in only 4 of 100 malpractice cases in one study, and all four involved rare conditions. [1] Other cognitive errors, such as faulty data gathering and information synthesis, occurred frequently in the cases studied and were often compounded by faulty systems such as equipment and organizational issues. Cognitive scientists who have analyzed diagnostic errors point out that the way physicians reason, formulate judgments, and make decisions works well most of the time. In some instances, however, cognitive rules of thumb and shortcuts lead to error. Examples include memories of former cases, the way information is presented and framed, obedience to authority figures, and premature closure of the diagnostic process. [2]  These cognitive “pitfalls” are inherent in the process itself; another physician may well make the same errors.

Q  Do studies of OMIC claims data reveal these cognitive errors?

A  Yes. In a recent OMIC study, three conditions were frequently misdiagnosed: retinal detachment, glaucoma, and foreign bodies. Retinal detachment and glaucoma were often missed if the patient had ocular comorbidities that could explain some of the symptoms, leading the ophthalmologist to assume it wasn’t necessary to complete a comprehensive evaluation, including a dilated eye exam. Retained foreign bodies were missed when the physician did not obtain an adequate history or failed to order x-rays to rule out their presence (see Closed Claim Study). Systems issues, particularly office appointment scheduling and follow-up protocols, also contributed to patient harm and led to settlements. When an on-call physician did not notify his staff of a patient due to come in the following morning after an ER consultation, his staff would not schedule the appointment, citing the office policy of declining public aid patients. After the child developed a corneal ulcer and needed a transplant, the practice settled for $1,000,000. Some conditions manifest themselves more clearly with time, and are often correctly diagnosed at the follow-up visit. If the patient does not show up for the visit, and staff do not notify the ophthalmologist of the missed appointment, an opportunity to intervene is lost. (See OMIC’s “Telephone Screening of Ophthalmic Problems” and “Noncompliance” at www.omic.com.)

Q  What strategies do cognitive scientists suggest to improve the decision-making process?

A  Strategies that encourage physicians to stop and examine their thinking process may help. Two key safety steps are: 1) pause to consider what else could produce the same signs and symptoms, and 2) entertain, however briefly, the worst possible scenario. By developing a differential diagnosis, the ophthalmologist can determine not only when a complete, dilated exam is required, but also when additional tests are needed to rule out vision-threatening conditions. A diagnosis that does not account for all of the signs and symptoms needs to be reconsidered, as does one that leads to a treatment plan that is not effective. When the patient’s course is unexpected, start over by reviewing the record with an open mind and asking questions such as “What else might be going on?” These strategies might prompt additional testing and examination, an expanded differential diagnosis, and a clearer picture. [3]

Q  Why do you recommend disclosing the differential diagnosis to the patient? Doesn’t that just confuse the patient?

A  In a busy ophthalmic practice, it is easy to overlook the need to obtain a thorough patient history and to rely solely upon the information provided by the patient to you or your staff. The patient’s presenting “complaint” may be misleading or irrelevant unless specific questions are asked, or the patient may have been interrupted before he or she had time to give a full account of all symptoms. Make the patient part of the healthcare team from the beginning of the diagnostic process by allowing sufficient time for the patient to present his or her concerns. Disclose your differential diagnosis and treatment plan. Ask the patient to watch for new symptoms and to contact you if the condition worsens or does not improve before the next appointment.

1. Graber ML, Franklin N, and Gordon R. “Diagnostic Error in Internal Medicine.” Arch Intern Med. July 11, 2005; v. 165: 1493-1499.

2. Redelmeier DA. “The Cognitive Psychology of Missed Diagnoses.” Ann Intern Med. 2005; 142:115-120. For a detailed discussion, see Croskerry P. “Achieving Quality in Clinical Decision Making: Cognitive Strategies and Detection of Bias.” Acad Emerg Med. 2002; v. 9, n. 11: 1184-1204.

3. “Failure to Diagnose Traumatic Eye Injuries” and “Failure to Diagnose Giant Cell (Temporal) Arteritis” at www.omic.com.