Come on, admit it. You are making diagnoses at restaurants, at airports, literally everywhere. I can't tell you how many diagnoses I make when holiday shopping at the mall. I've made diagnoses in every area of medicine—from dermatology to neurology, from congenital defects to fulminating infections, from the trivial to the terminal. I have even postulated treatments that could be curative or palliative. I may share these diagnoses and possible therapies with my wife or another companion, but I never share them with the potential patient or victim.

This compulsive habit (or talent?) of making diagnoses is not unique to the medical community. Car mechanics on radio shows tell listeners that the noises in their cars are from the universal joint or a faulty baffle in the exhaust system. Grandmothers hundreds of miles away tell you in a letter what is wrong with your tomato plants. Music lovers tell the piano player which of the 88 keys is out of tune. Your mother-in-law regularly tells your spouse about your many flaws. But the medical community is different. We usually do not tell afflicted persons who are not our patients about their diagnoses.

My snap-diagnosis habit began in my freshman year of medical school, during the neuroanatomy course. Within weeks, my classmates and I were playing "What's my lesion?" We were doing the festinating gait of the Parkinsonian patient, the slap-footed walk of the tabetic patient, and the ataxic stroll of the patient with cerebellar disease. When I saw a cousin that summer, I thought he had syringomyelia, but it turned out that his peculiar gait was due to the fact that his underwear was too tight.

My physical diagnosis sessions in my sophomore year were taught at a VA hospital, so I thought that every big abdomen was full of ascites and that all pursed lips were those of smokers with emphysema. I was certain that the W.C. Fields look-alike with rhinophyma who worked at the corner grocery had a liver that went down to his knees and a chest wall covered with spider angiomata. As I entered my clinical years of medical school, my diagnostic vista expanded. I saw the Marfan syndrome at the mall, along with the more mundane varieties of arthritis, phlebitis, and episcleritis (versatility was my middle name). The little child in the stroller looked like a cretin to me, but I was sure his mother loved him nevertheless. In the public restroom, the man in the next stall seemed to be suffering from pronounced hypogonadism. Did I tell the victims of their maladies? Never!

As the years passed, the snap-diagnosis trait went from an obsession to a controllable hobby. I became blas&130; about obvious diagnoses. When my 14-year-old son, after passing an exophthalmic woman, said, Dad, did you see that lady with Graves disease? I barely turned my head. I am now looking for the great cases. Woe to you if you ever become, in the minds of other physicians, a great case. A great case is, for example, a woman with supernumerary nipples and a different variety of cancer underlying each of them. A great case is a man with three testicles but no penis. It is someone with incurable cancer who now has an MI and a strangulated hernia. You get the picture. We medical people are obsessed with the grotesque.

My mall specialty is now, in essence, a search for acromegaly. This disorder, caused by the overproduction of growth hormone by the pituitary gland, leads to classic physical alterations that evolve so insidiously over the years that the patient and his or her family and friends are oblivious to the changes. The disorder is associated with enlargement of the hands and feet, prognathism, prominence of the brow, and a general coarsening of all facial features. Eventually, patients with this disorder all begin to look alike. The insidious nature of the evolution is characterized in the following example. Some years ago, one of the residents training in radiology at our medical center was a man with obvious acromegaly. I assumed that he had had previous therapy and that his pituitary tumor had been resected. On a day in early July, a new medical intern entered my office and informed me that this radiology resident had acromegaly. I answered that everybody knew that. "But does he know it?" queried the intern. When the issue was pursued, it became apparent that the resident didn't know about it ("You're full of——," he said, when I suggested it). He had his surgery and lives happily ever after.

Since that July day, I have searched for persons with acromegaly. A few months later, I spotted one at an amusement park. While my sons were on the various rides, I made four passes at the man, clearly establishing the diagnosis in my mind. But I didn't tell him! I curse myself to this day for not stopping him. Perhaps he knew, but maybe he was like our radiologist, oblivious to the slow-growing tumor in his head. Since that day, I have steeled my resolve. I patrol the malls, looking for this disorder. Now I tell the patients about their suspected diagnosis. Don't mean to brag, but I've had some success in my acromegaly watch. I've had 3 previously treated cases, 2 new diagnoses (they took their business to another endocrinologist), 4 who couldn't be convinced that I wasn't an insurance salesman, and 6 who said "Beat it, Buster!"

@copy; 1995 American College of Physicians