Question: A psychiatrist refers a young woman for possible pneumonia. Her symptoms include episodic dyspnea and hyperventilation. The resident obtained a history of chronic anxiety and depression, for which the patient takes diazepam. There was a history of cigarette smoking and use of oral contraceptives. Physical examination was normal except for obesity, tachycardia, restlessness, and breathlessness. The patient’s cardiovascular and respiratory exams were otherwise normal, and the chest x-ray was read as unremarkable.
The woman was sent home with the tentative diagnosis of anxiety neurosis, but was found dead 24 hours later. Autopsy revealed a massive pulmonary embolus originating from a pelvic vein thrombus.
Which of the following observations is correct?
A. Failure to diagnose is the most common basis for a medical malpractice claim.
B. It is likely that this case will be settled in the decedent’s favor, because all four elements of negligence are satisfied: duty, breach of duty, causation, and damages.
C. The doctor may have been biased, because this was a patient with a psychiatric history.
D. This is an example of framing and anchoring cognitive failure rather than lack of knowledge.
E. All are correct.
Answer: E. This case is modified from an example in the literature on diagnostic errors (N. Engl. J. Med. 2013;368:2445-8). The resident focused his attention on the psychiatric referral diagnoses of pneumonia and anxiety, overlooking the many risk factors for pulmonary embolism that included obesity, cigarette smoking, and the use of oral contraceptives. The case satisfies all four elements for the tort of negligence, and will most likely be decided in the patient’s favor.
It is usually not a lack of knowledge that leads to a diagnostic error, but problems with the clinician’s thought process (cognitive failure). Although physicians well know the pathophysiology of pulmonary embolism, its protean signs and symptoms overlap those of numerous other diseases, and this important diagnosis is frequently missed – in 55% of fatal cases, in one study.
Terms such as "missed diagnosis," "wrong diagnosis," or most commonly "diagnostic error" are used in the medical literature, but the unifying malpractice nomenclature is "failure to diagnose." The term includes the failure to refer to an appropriate specialist if customarily required.
Although reduced physician-patient encounter time is sometimes blamed for missing a diagnosis, this is of course not a legitimate legal defense. There is litigation aplenty over failure-to-diagnose conditions such as myocardial infarction or a dissecting aneurysm (Cardiology 2008;109:263-72). Other examples are pulmonary embolism, appendicitis, ectopic pregnancy, meningitis, cancers, and fractures.
In a recent study in primary care settings (a Veterans Affairs facility and a private clinic), the authors were able to identify diagnostic errors from electronic health record triggers based in part on a patient’s unexpected return visit (JAMA Intern. Med. 2013;173:418-25). Of 190 cases, they identified some 68 unique diagnoses. Commonly presenting with atypical or nonspecific symptoms, these conditions included pneumonia, congestive heart failure, acute renal failure, cancer, and UTIs. Lapses in bedside history taking, physical exam, and test ordering were noted. Significantly, there was no documentation of an initial differential diagnosis in 80% of misdiagnosed cases.
Diagnostic errors occur more frequently than generally supposed, especially in specialties such as primary care and emergency medicine. They are the most frequent reason for a malpractice claim.
In a review of more than 350,000 closed claims reported to the National Practitioner Data Bank over a 25-year period, researchers from Johns Hopkins University concluded that, "among malpractice claims, diagnostic errors appear to be the most common, most costly, and most dangerous of medical mistakes." They found such errors in 28.6% of all cases, accounting for the highest proportion (35.2%) of total payments.
Diagnostic errors also caused the most severe injuries, especially in hospitalized patients (BMJ Qual. Saf. 2013;22:672-80). It has been reported that roughly 5% of autopsies uncover a diagnostic error that was amenable to appropriate treatment, and some 50,000 annual hospital deaths may be the result of a delayed, incorrect, or overlooked diagnosis.
Diagnostic errors have multifactorial causes, divisible into system-related and cognitive factors (Arch. Intern. Med. 2005;165:1493-9). In a review of 100 internal medicine cases identified through autopsy discrepancies, quality assurance activities, and voluntary reports, the researchers found the absence of fault in only 7% of cases. In the remaining 93 cases, system-related factors were present in 65% and cognitive factors in 74%.
The most common system-related factors were defective, inappropriate, or inefficient policies and procedures, and dysfunctional teamwork and communication. Clinicians know too well that procedural errors can lead to tests that go unordered, results that go unnoticed or misfiled, or a patient who fails to follow up with a referral or return appointment.