Friday, November 9, 2012

Wrong Diagnosis


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 All the best evidence protocols are worthless in the face of the wrong diagnosis. With the efforts to standardize medical treatment, reduce costs and enhance patient safety, planners pay little attention to missed or wrong diagnosis. Disease in my formal medical training was defined as a maladaptation to the environment, and at some level, indeed it is. Medical science and the physician’s art define the causes of that maladaptation as a diagnosis or syndrome. Unfortunately many diseases have common signs and symptoms. The body has a limited number of ways to respond to disease and there are so many diseases and syndromes – more than we can remember.  The identification of a diagnosis, therefore, may be uncertain at best.[1]  

Two thousand four hundred and fifty years ago Hippocrates confronted the challenge of diagnosis with terms meticulously describing the manifestations of disease. His precise descriptions and inductive reasoning lead to the abandonment from mythology in diagnosis and from the concept of disease as a punishment by the gods. His diagnosis was correct in that it was a precise description of its effect.

Today, however, with far greater knowledge of pathophysiology we struggle with identifying the cause of our patients’ problems. We try to identify the diagnosis in order to relate a treatment plan that is safe and yields a prognosis favorable to the patient.  What is the problem? With what little research there is on wrong diagnosis and missed diagnosis, we find up to a 20% error rate. Autopsy findings prove error rates much higher. In some cases, such as pulmonary embolism or aortic aneurism, the error rate runs as high as 60%[2] Outpatient ENT errors run high as well and most hospital admissions for pneumonia are signed out as community acquired pneumonia unidentified.

Many causes lead us to submit an erroneous diagnosis. Perhaps the greatest problem is the number of layers of cause and effect that we deal with. Is it a gross diagnosis or a tissue diagnosis or tomorrow a bio-molecular diagnosis – even genomic?  Is it left lower quadrant pain, a left ovarian mass, a corpus lutein cyst, a seromucinous cyst adenocarcinoma and if the later, what proteinomic predisposition?

Autopsy has gone out of style. Two hundred years ago Marie Francois Bichat wrote over his autopsy room in Paris, “Death comes to the Aid of the Living.” The abandonment of autopsy must be economic. Maybe insurance companies refused to pay for it. Patient’s families have always objected. The hospital does not want the responsibility. The pathologist finds it a low marginal return activity. For whatever reason, autopsy -- except for forensics -- seems a lost art. We find clinical pathological conference and morbidity and mortality conference replaced by the x-ray conference. With the abandonment of autopsy we have lost the gold standard for definitive diagnosis.

The CAT scan has replaced the autopsy in an intellectual sense, and that is all wrong. The CAT scan is expensive, far more so than an autopsy and is by no means definitive at the tissue, cellular and molecular level. Although X-ray conferences are contemporary, and bring together multiple specialties and the diagnostic suggestions of the group, they still may still fail to yield the right answer. CAT scans done extensively in place of careful differential diagnosis and basic cognitive disciplines cost the patient and the health care system enormously. With an initial wrong presumption the addition of added unnecessary tests and procedures lead to decreased patient satisfaction, safety and poorer outcomes. --- “First, do no harm!”

Patients are different. There molecular biology may be as varied as their noses. Statistically derived presumptions, may fail to account for geography, ethnicity or individual circumstances. Additionally, the physician may decline to write a diagnosis that may cause the patient to be ineligible for insurance, induction into the military or some other sensitive job such as hospital privileges for a doctor or class I medical for an airline pilot. These are usually minor omissions, but together they deny any meaningful analysis of a database based on the diagnosis.

Our very regulations seeking standardized care may cause a more insidious error rate based on the diagnostic requirement for laboratory or other diagnostic studies. The same may apply to treatment plans – a treatment looking for a diagnosis. A similar diagnostic distortion occurs, when the diagnosis is altered or selected for reimbursement purposes. Hopefully these alterations are harmless to the patient, but in some context can lead to a wrong presumption in a future event that misses a lifesaving solution.

Overconfidence, assumption, snap diagnosis and omission of essential parts of the history and physical contribute to errors as well.[3] We do not keep statistics on wrong diagnosis, but the trial lawyers do, and they can tell us something.  Graber et al chronicle the size of the missed diagnosis problem which results in between 40,000 and 80,000 deaths a year in the US. The problem may actually be greater.[4]

Cognitive scenarios as presented by primary care specialty boards, the review of systems together with listening to the patient, a complete history and physical at least for the organ system involved will go far. But the association of findings with the vast number of possibilities suggested by these findings presents a challenge to the clinician. It is a challenge that medical schools can meet with appropriate lists, current terminology and criteria for diagnosis  -- most of all a vigorous CME program. Johns Hopkins will hold a conference on wrong diagnosis this month.[5]



[1] Delaney; Munro: Diagnostic difficulty and error in primary care; Family Practice 2008; 25 (6) 400-413
 
[2] Berner, Graber; Overconfidence as a cause of diagnostic error in medicine; Am J Med 2008;121: S2-S23
 
[3] Bringing Diagnosis Into the Quality and Safety Equations; Graber ML; Wachter RM, Cassel CK. JAMA. 2012; 308(12): 1211-1212.
 
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1 comment:

  1. I see the greatest contents on your blog and I absolutely love reading them.cme conferences

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