Introduction and Background

CASE TEACHING IN MEDICINE A SERIES OF GRADUATED EXERCISES IN THE DIFFERENTIAL DIAGNOSIS, PROGNOSIS AND TREATMENT OF ACTUAL CASES OF DISEASE BY RICHARD C. CABOT, A.B., M.D. (Harvarp) INSTRUCTOR IN MEDICINE IN THE HARVARD MEDICAL SCHOOL AND PHYSICIAN TO OUT-PATIENTS AT THE MASSACHUSETTS GENERAL HOSPITAL BOSTON, U.S. A. D. C. HEATH & CO., PusiisHers 1908 Ra COPYRIGHT, 1906, By D.C. HeatH & Co. A137 Cle 1908 INTRODUCTION THE most important lesson to be learned by every student of medicine is the art of recognizing the physical signs of disease, —a displaced cardiac apex, a succussion-sound, an Argyle-Robertson pupil, a malarial parasite. With these basic facts we can become familiar only by direct contact with patients and by long practice. But these data of physical diagnosis have to be interpreted. They do not crystallize spontaneously into conclusions. They do not arrange themselves in those significant groups which we call diseases. They have to be worked up into diagnoses by a reasoning process, and this reasoning needs practice. A man may collect with accuracy and thoroughness the data of the history and the physical examination, and then find that he does not know what they mean, — what judgment can safely be based upon them, which of them are of primary and which of secondary importance. For this secondary and relatively easy step in the development of medical knowledge, one does not need the actual presence of a patient. With a book and a teacher it can be learned anywhere and at any time as well as in the clinic. Indeed it is easier to concentrate atten- tion upon the processes of memory, comparison, and exclusion, which form the essence of diagnostic reasoning, if the senses are not distracted by the presence of the patient. A/ter the student has learned to open his eyes and see, he must learn to shut them and think, and when he is thinking the less he has to distract him the better. To aid the teacher in training his pupils to think clearly, cogently, and sensibly about the data gathered by physical examination is the object of this book. I present these cases because I have found them useful in this type of instruction. They are selected from a much larger number which I have used and tested in “case-teaching exer- cises” during the past eight years. ADVANTAGES FOR THE STUDENT 1. By means of these cases and others like them we can present a boundless wéalth of material, unhampered by the narrowness of our clinical resources. vii 44044 viii INTRODUCTION 2. We can present it precisely as it is met with in practice, — the important facts deceptively entangled with what is irrelevant and misleading. Then we can help the student to disentangle the essentials, 3. We can present cases with portions omitted, cases therefore blind and puzzling as they would have been in actual practice had the physician forgotten, as we all forget sometimes, to look for and record certain essential facts. 4. From a point of view distinctly differing from that of the lecture, clinic, or quizz, we can test the pupil’s ability to gather up and use the knowledge he has acquired from various sources — from his reading, from the laboratory, from bedside study, and from watching his teachers at work. Case-teaching is thus a valuable method of general review. 5. We can teach the student how to group isolated symptoms into well-knit diagnoses. ADVANTAGES FOR THE TEACHER 1. By using this method a single teacher can keep a large class of students actively busy. They are not merely listening or watching; they are doing the work of construction themselves. In lectures or large amphitheatre clinics the whole class is managed by one teacher, but the teacher does the work and hence the student’s gain is relatively slight. In laboratory exercises the student does the work, and reaps large profits provided there are teachers enough; but one teacher can rarely supervise more than eight or ten students. In case-teaching, however, the whole class works yet only one teacher is needed. 2, No expensive apparatus or instruments are needed. A room, some books, and a teacher are the only accoutrements called for. 3. By the students’ answers and by their questions — which soon come thick and fast if encouraged — the teacher can find out the gaps in each student’s knowledge. Knowing these deficiencies early in the year (and not merely from the revelations of final examination books) he is in a position to codperate with each student in getting the deficien- cies filled in, —a position very pleasant for both the student and for the teacher. 4. Very effective lessons on prognosis, on treatment, and on the difficulties likely to be met with in practice, can be given in connection with these cases. Meruop or Usina THE CasES 1. The teacher first reads aloud the case to be discussed while the students follow in their case-books — from which the diagnoses and INTRODUCTION ix the answers to all questions are omitted. As he reads, the teachermay comment on or explain the text so as to make its meaning clear. 2. A member of the class is next called upon by name, to summarize the case, to point out whether it is acute or chronic, and what organs or systems are especially involved. Students must always be called on by name, else the exercise will be a failure. 3. The students are given five or ten minutes to think over the case and then each writes, signs, and hands in a tentative diagnosis and one or two alternatives on a slip of paper. Each man is thus forced to commit himself before he hears the case discussed and before he has gotten any ideas from the other students. By looking over these slips rapidly the teacher can get a good idea of where the class is in relation to the case. 4. The class is now prepared to discuss the case. The teacher calls for diagnoses and writes upon the blackboard all that are at all plaus- ible, discarding only the wild guesses. Next, beginning with the least plausible diagnosis, he calls upon the man who has suggested it to give his reasons for it, — the data supporting it. Then the class is asked to bring up the points against it. If the objections are fatal ones, this diagnosis is scratched off the list; if not, the question is left open until the other diagnoses have been discussed. “Which diagnosis has the most and the strongest arguments in its favor and the fewest and weakest against it?” is the final question, and if there is much doubt about this a vote may be taken so that each man may be put for the second time on record. 5. The teacher then announces the actual diagnosis of the case as it was proved by operation, by necropsy, or by the course of the symp- toms. This will be awaited with a hush of excitement and greeted with a buzz of interest if the previous discussion has been well planned. “Why didn’t you all make that diagnosis? What was forgotten or misinterpreted?” are the questions next taken up, and the diagnostic part of the exercise is thus brought to a close. 6. Prognosis and treatment are next talked over. Prognosis as to life, as to the probable duration of the case, and as to likelihood of complete and permanent recovery, are separately discussed in each case. In treatment it is well to begin with questions as to the general dietetic, 1 The only failures that I have seen with this system have been due to the fact that the teacher directed his questions at the whole class or pointed them at a particular student without naming him. If the teacher calls the name from a printed list, and has the men sit always in the same places, it is easy to learn them in the course of a few exercises. x INTRODUCTION hygienic, and mechanical measures likely to aid this particular case, and to end with drugs. Precise account of the way of administering drugs, their doses, and the full directions to be written on the boxes or bottles containing them, should be demanded. GENERAL. SUGGESTIONS 1, I have found it important to encourage questions, not only such as are strictly relevant to the matter in hand but any questions that occur to any student during the exercise. If the teacher knows the answer to the question he should refer it to some other student and ask him to answer his classmate. Only if no one in the class knows the answer should the teacher give it himself; for the process of answer- ing serves to fix the fact in the student’s mind and he should never be deprived of this benefit. 2. If the teacher does not know the answer, as must frequently be the case when the students are really intelligent and interested, he should say so and then tell the student where to look for it. 3. “What symptoms are missing in that case? What typical signs are absent?” are questions which I have found of value for testing students in a vulnerable quarter. Criticism of the history or of the physical examination as printed in the case-book may also be invited with profit. 4, In connection with one or another of the cases presented in this book the teacher will find a good opportunity to illustrate the common failures and errors of young physicians, to describe his own ways of meeting emergencies, and to detail practical devices for the care of the sick, points not often found in books. Tue CHARACTER OF THE CASES HERE COLLECTED 1. A large proportion of these cases end either with autopsy or with operation, which gives a rather sombre tone to the whole. I have selected a good many of such cases because in case-teaching we need to be able to announce definitively the actual diagnosis, and this can be done with absolute certainty only when some one has seen (before or after death) the result. 2. Some of the cases turn out to be rare ones, but in the discussion of their differential diagnosis we have to deal mostly with common diseases and to say fully as much about them as about the rarer disease which was actually present. Hence most of the time of the class isspent in the study of diseases such as they are likely to meet in practice. 190 Martzoro Sr., Boston. Fesrvary, 1906. CASE TEACHING IN MEDICINE 2 CASE 1 A liquor dealer, 47 years old, is seen December 15, 1904. His father died at 67 of “obstruction of the bowels,” his mother at 63 of pneumonia. He regularly used whiskey and beer to excess up to 1891 when he had an attack of bloody vomiting after a debauch. He had a similar attack in 1895 and again in 1902. He never was kept in bed more than a few days, and always returned to business within a week. After each attack he gave up all alcohol for periods varying from six months to two years and then relapsed into his former habits. He has suffered for years from digestive disturbances, “sour stomach,” which have been much worse during his periods of alcoholism. After twenty months of abstinence he began to drink about three months ago, and since then has complained of anorexia, pain, eructation of gas, nausea, and vomiting. The pain is located in the epigastrium, comes on ten to fifteen minutes after eating and is relieved by vomiting. On thie afternoon of December 11 he vomited a small quantity of bright red blood, and since then he has vomited after nearly every meal, but he has noticed blood only on one other occasion, two days ago, when he threw up nearly a pint. He has noticed black stools for several days. He has recently lost about 15 lbs.; present weight 185. Mucous membranes pale. Heart normal in size, action regular, soft systolic murmur at apex, not transmitted. Pulmonic second sound not accentuated. Abdomen tympanitic throughout, slight tender- ness on pressure over epigastrium. Liver dulness extends from fifth interspace to two fingers’ breadth below costal margin where a smooth edge can be felt. Lower edge of spleen felt on full inspiration. Physical examination otherwise negative. Pulse 100, regular, of good quality. Temperature 98.4°. Urine, sp. gr. 1020, acid, no sugar, no albumen, Hg. 50%, red cells 3,172,000, no nucleated cells. Leucocytes 9200. 1. What is the type of anemia in this case? Typical secondary. 2. Significance of the patient’s family history? None whatever. (Teacher may bring up here a discussion of the problem: in what cases is family history of value? ) 3. What causes produce tarry stools? Bismuth, iron, blackberries, blood from high up in gut. . How do you interpret the cardiac signs here present? Functional murmur. . What are the commonest causes of splenic enlargement? Typhoid, malaria, tickets, cirrhosis, leucemia, anemia. 6. What causes of hematemesis should be considered here? Gastric or duodenal ulcer, cirrhosis, aneurism. 7. Diagnosis? Prognosis? Treatment? Diagnosis: Hepatic cirrhosis, ruptured esophageal varix, secondary anemia, pas- sive congestion of stomach. Prognosis: Probably one to two years to live. ‘Treatment: Stop liquor, treat anemia, regulate diet. Possibly Talma’s operation. on 4 CASE 2 A fireman of 26 was exercising engine-horses, riding one and leading another. The led horse fell and, as he struggled to rise, wrenched severely the arm of the fireman, who had not let go the halter. He thought nothing of it at the time, but twenty-four hours later began to be distressed by a sense of weight and pressure beneath the sternum, near the attachment of the wrenched pectoral. Under medical advice he was laid off duty and treated with liniments and counter-irritation, but without relief. Three weeks’ vacation in the country benefited him, but on his return to work he was unable to drive or even to put on the foot brake without great exhaustion. Now he cannot walk a block fast without feeling tired out and experiencing a sense of pressure under the sternum. His wife tells him that he moans and grinds his teeth in his sleep. He has lost flesh, strength, and color. The heart’s apex is in the fifth interspace and mammary line. There is reduplication of the apex second sound, and at the fifth left costal cartilage a systolic murmur, louder in the recumbent position. The pulmonic second sound is slightly louder than the aortic. . Interrupted inspiration is detected in both fronts and both inter- scapular regions, also transient rales in the sixth intercostal space in the left axilla. Abdomen negative. The blood and urine are normal. 1. What is the usual significance of moaning and teeth grinding during sleep? Functional cerebral irritation; no organic disease. Common in rickets and in neurotic children. Popular fallacy that “worms” are the cause. Types of delirium and of somnambulism may be here discussed. How is the loss of flesh, strength, and color to be explained? (See below under diagnosis.) Causes of emaciation and of pallor may be considered here. 3. How are cardiac murmurs affected by change of position? All systolic mur murs are louder in the recumbent position. Presystolic murmurs are louder in the erect position, while diastolic murmurs are unaffected. 4. Diagnosis? Prognosis? Treatment? The Diagnosis is traumatic neurosis. Aneurism is excluded by the age, the acute onset, and the lack of evidence of mediastinal pressure. Local trauma is not imaportant, for after the vacation the symptoms were general, not local. Chronic latent diseases “lighted up’ by the accident (phthisis, anemia, nephritis) are excluded by the negative physical examination. Traumatic neurosis is further suggested by the interval between the accident and the onset of symptoms. (Cerebral hemorrhage may come on many hours after a blow, but always produces physical signs of brain injury, as paralysis or aphasia.) The Prognosis is good if treatment is wise. He should be well in six months, but may have to change his occupation. The Treatment is first encouragement and reassurance. Everything should be done to attract attention from the seat of supposed injury. Local appli- cations (here given) are the worst possible treatment. Advise work of another kind, a bitter tonic for appetite, and hydrotherapy for sleep. s 6 CASE 3 A medical student of 25 has been troubled with his joints for ten years. Attacks of pain and stiffness lay him up whenever he is sub- jected to any strain, mental or physical. He has had little or no fever, he thinks, in any of the attacks, but the pain and swelling have been considerable. He has, as a rule, one or two bad attacks each year, with a week or two in bed. The knees, ankles, hips, hands, wrists, and elbows have been affected, and in every case some stiffness and more or less swelling has remained after the pain left. Both sides are affected nearly alike. Of late years the attacks have grown less severe, especially since his family has grown more prosperous and more harmonious. He is now able to attend to most of his medical work. Examination shows no motion in the left wrist and very little in either ring finger. The range of motion in the knees and elbows is also considerably limited. The fingers are cold, mottled, and damp. Some of the finger joints and both wrists are doughy and semi-fluctuant. There is no evidence of bony enlargement anywhere. The heart and internal viscera are negative, but the boy is pale “and rather thin. Blood and urine normal. 1. Types and causes of arthritis? Infectious (including acute “rheumatism”) atrophie, hypertrophic, gouty, neuropathic, hzmophilic. 2. What varieties of arthritis are often associated with cardiac disease? Only the infectious types: ¢.g., “rheumatic,” septic, gonorrhcal, scarlatinal, pneumo- coccal. Tuberculous and syphilitic infections of joints are rarely associated with endocarditis. 3. What important data are not mentioned in the above description? X-ray examination, data regarding gonorrhea and regarding muscular atrophy. 4. Diagnosis? Prognosis? Treatment? Diagnosis: X-ray examination showed marked atrophy of the articular ends of the bones. There was marked muscular atrophy. No history of gonorrhea or of any other infection. The absence of any known infection, the long progressive course in a young person, the symmetrical involvement of joints, the vaso motor signs, the absence of marked fever, and the X-ray evidence all point to atrophic arthritis and serve (with the negative condition of the viscera, blood, and urine) to exclude other varieties. Prognosis: Most cases slowly progress, but with favorable environment, hygienic and psychic, some cases are arrested, as in fact this one was, before crippling damage occurs. In such cases the injured joints never return to the normal, but the patient learns to adapt himself. Any mental or physical strain is likely to produce recrudescence, more or less serious. ‘Treatment: Drugs have no effect save as they may help to improve the general nutrition (bitters, iron, arsenic). Salicylates do harm. Rest in the acute attacks, with warmth to the joints, forced feeding, out-door life so far as the joints permit, encouragement and freedom from worry, are important aids to recovery. The excision of ankylosed joints may be necessary. 8 "CASE 4 A married woman, 43 years old, is seen April 9. Family history negative. Has had three children, the youngest being twenty years old, and no miscarriages. Eighteen years ago she began to suffer from profuse menstruation which became so excessive and exhausting that eighteen months ago the uterus and appendages were removed. In spite of the cessation of the hemorrhages she says that she has lost ground and grown paler more rapidly since the operation. For the past six months nose bleeds have been frequent and at times so ex- cessive that the nares have been plugged. She has had “feverish turns,” lasting several days at a time, but her chief complaint has been of weakness, great dyspnoea, palpitation, and attacks of faint- ness. Micturition has been more frequent for the past few years, but ~ without any polyuria. Her legs and ankles have been considerably swollen, but this has been much less apparent lately. About a month ago she had a copious epistaxis, followed, four days later, by a second, less severe, and has