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an online version of the magazine Winter 2005
Annals of Hopkins

When Diagnosis Reigned

Harvey holds forth during a 1950 CPC in a lab classroom.
> Harvey holds forth during a 1950 CPC in a lab classroom.
By Janet Farrar Worthington

In the days before sophisticated laboratory testing, the brilliant Mac

Harvey used a weekly conference to demonstrate how clinical evidence could reveal a patient's medical problem.


If you're in your 30s or younger and the name A. MacGehee Harvey sounds familiar, it might be because you've walked through the Hospital building named for him. Or if you're an M.D., you've no doubt ploughed through the classic textbook “Differential Diagnosis” that Harvey wrote with his fellow internist James Bordley.

But if you're a bit older, you might have actually had a chance to see the master diagnostician at work at the bedside. Or, the next best thing, you might have been in the audience during the weekly clinical-pathological conference that Mac Harvey conducted every Wednesday for 27 years.

The CPCs were a tutorial, a working session in which Harvey demonstrated the art of medicine. A few days ahead of time, he would receive all the clinical evidence available on a patient. Then, he would meticulously go through every clue that could help him decipher the person's medical problem and reach a conclusion. But there was always a catch: The pathologist knew the real diagnosis. Because the patient was dead, and the verdict had been discovered, or confirmed, at autopsy.

Clinical-pathological conferences at Hopkins date back to the 1890s, when the Hospital was just an upstart, and all the name-brand medical schools were in Europe . Started by pathologist William Welch (one of the institution's Big Four founding faculty), the CPCs were based on an idea developed at Massachusetts General Hospital . But Welch made the Hopkins version tougher. Instead of being handed a prepared case summary, the clinician deciphering the case would get only the raw material—the patient's charts, X-rays and test results. Then, once the clinician had reached a conclusion, the pathologist would discuss the postmortem findings and reveal the true diagnosis.

It was a characteristically American exercise, Harvey often said, because a professor at one of the European schools would never have risked being corrected by his colleagues in front of medical students and house staff. Of course, for Harvey , that wasn't much of a risk. In 1945, at the age of 34, he had made the cover of Time magazine when he was named director of the Department of Medicine at America's most revered medical institution—Johns Hopkins. “To older, greyer doctors, Dr. Harvey's selection was a surprise,” the cover story said. “It should not have been.”

By that time, Harvey was already world-famous for the wealth of clinical information in his brain and his unusual ability to sift through that information, nugget by nugget, and match it to clues gleaned from the patient's history and physical exam. Instead of saying, Here's everything you need to know about congestive heart failure, Harvey would use a particular patient as his starting point and move outward to cover the whole topic. Over the next generation of medicine, this method of carrying out and teaching differential diagnosis—a systematic process of elimination in which the diagnosing physician asked, What else could it be? and then discarded all but the right answer—became the guiding principle for thousands of medical students and residents who were trained at Johns Hopkins.

The format for the CPCs was straightforward. Every year, Harvey would ask a member of the Osler house staff to work with a counterpart in pathology and select challenging cases from the Department of Pathology's massive library of autopsy files. When the two residents found a promising case, they would present it to pathologist Arnold Rich, who ran the sessions (later, this role was filled by pathologist Ivan L. Bennett). Rich's lectures were notorious among second-year medical students for their hardball questions like, What is death? or What is life? He filled students with fear, and they were terrified that they might be called on in these sessions. “ But Dr. Rich was actually delightful and had a great sense of humor,” says Wilbur Mattison, '52, who spent two years during his residency helping choose the cases for the CPCs.

Pathology whiz Arnold Rich, left, with lung expert Louis Hamman.
>Pathology whiz Arnold Rich, left, with lung expert Louis Hamman.

Rich had two criteria for a CPC case. There had to be a clue to the correct diagnosis somewhere. (“We learned early on, that you didn't feed Rich the clue right away,” Mattison says.) It could be a note in the medical student's work-up, or in the nurse's notes, but it had to be there. And the pathology had to be incontravertible. If Rich had a hard time making the diagnosis, he was much more likely to accept the case. The CPC itself took place every Wednesday at noon in the pathology lecture room. Harvey would spend about 40 minutes giving the differential diagnosis. When it was Rich's turn, he used an ancient arc light projector that sputtered and smoked to show slides of the pathology that revealed the diagnosis. The visuals were low-tech, but the teaching from both doctors was first-rate.

Several years later, in a lecture to third-year medical students (later reprinted in the New England Journal of Medicine), Philip A. Tumulty, a Harvey trainee who went on to become one of Hopkins' greatest clinicians, may have summed up best the qualities that made his mentor's (and other master diagnosticians') performances so unforgettable. He was “meticulous in accumulating the historical and physical data from the patient. He interprets the clues derived from the physical changes with the precision of an experienced detective. His analysis of the clinical evidence is methodical and disciplined. The reasonableness of his logic makes his conclusions appear inevitable.”

But what may have been most extraordinary about Harvey 's diagnostic demonstrations throughout hundreds of CPCs was that they depended solely on his clinical acumen. They took place in an age when there were few lab tests and only three ways to look inside the body: an X-ray, a barium test, or by exploratory surgery. His knowledge also encompassed the whole field of internal medicine. “In the days before subspecialties,” Mattison says, “Dr. Harvey was a superb endocrinologist, rheumatologist, gastroenterologist, cardiologist, even neurologist.”

The weekly CPCs continued at Hopkins until the 1980s. Then, over the next decade, as new forms of imaging and sophisticated tests became routine parts of the diagnostic process, the conference was cut back to about four times a year. But today, the CPC flourishes again. The grand old forum for teaching physicians the art of diagnosis has returned on a monthly basis. New cases (including images) are posted on the Internet two weeks ahead of time; the clinician's and pathologist's verdicts are posted afterward. And the School of Medicine Clinico-Pathological Conference Web site declares unequivocally: “Research has shown that problem-based learning is highly effective. The CPC works.”

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© The Johns Hopkins University 2005