School of Medicine professor publishes article in Journal of General Internal Medicine
Nov. 30, 2012 - Detective work by physicians trying to diagnose a complex medical case found that revisiting the case history after initial physical examinations and preliminary diagnostic tests led to earlier diagnosis while eliminating more costly and invasive tests. These were the conclusions of "Getting to the Right Question," Exercises in Clinical Reasoning, published online in the "Journal of General Internal Medicine," which looked at the case history of a woman with Sjögren's Syndrome.
Dr. Todd Cassese
"Health care costs rise and diagnostic reasoning suffers when physicians start collecting excessive information from expensive and extraneous testing," says lead author Dr. Todd Cassese, a professor of medical sciences and director of the clinical arts and sciences course at the Frank H. Netter, MD School of Medicine, scheduled to open in Fall 2013.
"Historically, 70 percent of diagnoses are made from medical history alone, so diagnostic reasoning is an important tool in the physicians' bag that can be honed by working through this type of case with its many twists and turns. Revisiting medical history is not only a 'cheap' diagnostic test, it's part of old fashioned 'doctoring' that belongs in every modern physician's repertoire."
The case history in question tells the story of a 49-year-old woman in good health, who experienced a sudden onset of weakness in her legs and arms. Three days later, the woman was hospitalized when she could no longer get out of bed.
Ten years prior to this incident, the patient had thrombotic thrombocytopenic purpura, a rare blood disorder that was treated with plasma exchange followed by a splenectomy. She had a family history of cancer; did not use tobacco, alcohol or illicit drugs; and did not take any prescription medications aside from an oral contraceptive. She was in good health prior to the onset of this illness.
The initial diagnostic considerations of the physicians caring for this patient included common causes of acute onset quadriplegia and the associated consequences of impending respiratory failure. Additional diagnostic information, including a very low potassium value and trouble acidifying her urine, led to consideration of a group of rare conditions collectively known as renal tubular acidoses (RTA).
Each preliminary conclusion triggered new hypotheses about the underlying disease. However, it wasn't until the patient was re-interviewed, a few days into her hospitalization, that the physicians had a eureka moment. They knew they had a diagnosis when she described ongoing problems over many years of dry mouth and dry, itchy eyes, indicative of Sjögren's syndrome, a systemic autoimmune disease in which immune cells attack and destroy the exocrine glands (notably in the lacrimal and salivary glands).
After being treated with potassium and bicarbonate supplements, the patient's weakness and muscle pain improved, and she was able to walk unassisted on her fourth day in the hospital.
According to Dr. Cassese, a traditional approach to this patient probably would have led to unnecessary testing including CT and MRI scans of the brain and spine.
"This case illustrates that when we approach a patient's condition with a preliminary hypothesis that is continually refined by the acquisition of evidence-based data, physicians become increasingly comfortable altering the order in which we proceed through patient workups," says Dr. Cassese. "This enables us to practice more cost-conscious care and eliminate unnecessary diagnostic tests."
However, he notes that one of the perceived barriers to physicians returning to the bedside before ordering many of these tests includes the traditional and well-rehearsed training that advocates asking a thorough and complete history only at the first patient encounter.
"We're advocating a different approach here," says Dr. Cassese, "Going forward physicians should shift the traditional approach from 'be thorough' to be hypothesis-driven.' No physician would ever ask a patient presenting with paralysis whether she suffered from dry eyes and dry mouth, but continual questioning and exploration finally elicited that information, when additional clinical information made those questions more appropriate," he added. "By revisiting our hypothesis after taking a judicious case history, blood work and an EKG, we were able to avoid a battery of extensive and invasive tests by returning to the bedside for an ongoing, albeit traditionally discontinous, medical history."