Correspondence

Clinical Problem-Solving: The Appropriate Degree of Diagnostic Certainty?

N Engl J Med 1995; 332:538-539February 23, 1995

Article

To the Editor:

The case presented by Thibault (Nov. 3 issue)1 illustrates a very common problem in clinical cardiopulmonary medicine. A simple objective test is widely available that would probably have averted the extensive and expensive workup.

The patient's peak flow should have been measured in the emergency room before and after treatment with the bronchodilator. I suspect the flow rate would have improved, as did his symptoms. Such evidence supports a diagnosis of reversible airway disease, or asthma. This patient could then have been instructed to measure and record his peak flow daily or when he had any episodes of chest tightness and shortness of breath. This record would have been helpful to his physicians in providing support for the diagnosis of periodic air-flow obstruction, reversible with inhaled bronchodilators.2

William R. Hammond, M.D.
Martha Jefferson Hospital, Charlottesville, VA 22902

2 References

1
Thibault GE. The appropriate degree of diagnostic certainty. N Engl J Med 1994;331:1216-1220
Full Text | Web of Science | Medline

2
National Asthma Education Program. Expert Panel report: guidelines for the diagnosis and management of asthma. Bethesda, Md.: Department of Health and Human Services, 1991. (NIH publication no. 91-3042.)

To the Editor:

In a middle-aged, male exsmoker with exercise-induced dyspnea, one must pursue the possibility of proximal coronary disease until there is exhaustive proof that it can be ruled out. We must not miss the diseases that have the greatest effects on our patients. The consequences of missing adult-onset asthma are substantially less serious than those of misdiagnosing unstable atheromatous disease. Few people die of asthma, but unstable coronary plaques are the major cause of death in industrialized countries. It is not just prudent and economically sound but humane to rule out abruptly symptomatic coronary disease by virtually any means. The “expense of health care,” to which Thibault dutifully alludes, is not just the cost in dollars but the human cost. The cardiac discussant deserves our applause and thanks from a properly served patient.

John Rudoff, M.D.
2630 S.W. Commonwealth Ave., Portland, OR 97201-3141

To the Editor:

Why were pulmonary-function studies and a methacholine challenge not performed in the case presented by Thibault? These simple tests would have confirmed the diagnosis of asthma, easily obviating the need for a workup that probably cost well over $5,000 without good evidence to pursue the course that was followed.

Michael P. Mehr, M.D.
Riverwood Clinic, Wisconsin Rapids, WI 54494

To the Editor:

The pulmonary consultant in this case should have heeded the diagnostic criteria enumerated in Guidelines for the Diagnosis and Management of Asthma, published by the National Heart, Lung, and Blood Institute.1 If pulmonary-function testing reveals air-flow obstruction that is reversible after bronchodilator therapy, asthma is the most likely diagnosis. A disease that affects 10 million Americans can be successfully diagnosed and managed, even if it is “only asthma.”

Howard J. Silk, M.D.
Medical College of Georgia, Augusta, GA 30912

1 References

1
National Asthma Education Program. Expert Panel report: guidelines for the diagnosis and management of asthma. Bethesda, Md.: Department of Health and Human Services, 1991. (NIH publication no. 91-3042.)

To the Editor:

Careful attention to the history and physical examination, along with pertinent skin tests, would have demonstrated that the patient was allergic to molds (he wheezed while raking leaves, which are loaded with various molds) and to house dust or dust mites (he wheezed while cleaning a room). The emergency room physician is to be commended for making the correct diagnosis and prescribing the appropriate therapy — a bronchodilator and an antiinflammatory–corticosteroid inhaler. Precautions against dust in the bedroom would have been helpful as well.

The pulmonologist and cardiologist obviously viewed the case from the narrow perspectives of their own specialties. It is fortunate that the patient had a normal coronary angiogram, or he might have ended up being treated with bypass surgery. The pulmonologist could have contributed to the solution of this problem by performing a methacholine challenge. The use of a beta-blocker with minimal justification in a patient who had asthma not only was wrong but could have made the disease worse.

This case shows why the cost of medicine is so high. Thousands of dollars were spent on unnecessary tests and procedures.

Leslie R. Coleman, M.D.
Stamford Hospital, Stamford, CT 06902

To the Editor:

As a practitioner of the art of medicine, I am struck by how technology was used and abused in this case. The clinical diagnosis was apparently not acceptable to the patient and practitioner, so numerous tests were performed essentially to prove negative results.

I am curious about what drove this set of circumstances. Was it the threat of a lawsuit by the patient? Was it the threat of a lawsuit by the physician who was practicing defensive medicine? Was it the fee-for-service system that allowed tests to be performed unchecked, although there were few or no indications for them — particularly coronary angiography? Why did the patient allow these tests to be performed, given that he was free of symptoms?

Donald W. Aptekar, M.D.
4500 E. 9th St., Denver, CO 80220

Author/Editor Response

Dr. Thibault replies:

To the Editor: Drs. Hammond, Mehr, Silk, and Aptekar all applaud the clinical judgment of the emergency room physician and decry the use of excessive tests and procedures. They suggest that a much simpler approach, such as the measurement of peak flow in the emergency room or a methacholine challenge (or both), would have been sufficient to attain a reasonable degree of diagnostic certainty. I agree that the methacholine challenge is a useful diagnostic test and that it is underused. The opinions of these correspondents reinforce the major point I intended to make.

Dr. Coleman suggests that allergy testing would have been helpful as part of the diagnostic workup for this patient. Allergy testing is low in cost and poses little risk. In fact, however, the diagnosis of asthma should have been made even if allergy tests had been negative.

Dr. Rudoff defends the pursuit of the diagnosis of atherosclerotic coronary disease because of the dire consequences of missing it. Clearly, this diagnosis must be pursued if the probability is high enough that the benefits of testing and treatment outweigh the risks. That balance between benefits and risks must be assessed for each patient on the basis of the history, physical findings, laboratory tests, clinical course, and response to therapy. In the patient I described, the evidence suggested that the probability of life-threatening proximal coronary artery disease was very low. The cost of attaining absolute diagnostic certainty in every instance is not just the economic cost to society but also the cost to the patient in terms of time, anxiety, and life-threatening complications. The most invasive approach is often not the most appropriate.

George E. Thibault, M.D.
Veterans Affairs Medical Center, West Roxbury, MA 02132

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