CHAPTER XXIL JAUNDICE Causes oF Jaunvice 715 Assoctatep Svptows 716 INTENSITY OF JAUNDK 719
» Catarrhal Jaundice. Catarrhal Jaundice . Tertian Malaria.
|. Gall-stones.
- Gall-stones wees . Pancreatic Cancer........
Acute Yellow Atrophy of the Liver.
CHAPTER XXIII
NERVOUSNESS
Case No.
Diabetes Mellitus. . 731
Phthi ‘ + 733
Suppurative Nephritis. 738
Endothelioma of the Pleura; Acute Serofibrinous Pericarditis and General Arteriosclerosis 738
Pernicious Anemia 739
Chronic Interstitial } 741 APPENDICES) sunyer ena ERY 748
INDEX. eee eee eee eee terete eee cena tense tet eset eet eeteeeee 747
DIFFERENTIAL DIAGNOSIS
INTRODUCTION
- THE PRESENTING SYMPTOM
Cases of disease present, as we say, certain leading symptoms. They thrust forward, like a soldier who presents arms, a complaint such as pain, cough, or “nervousness,” so that it occupies the foreground of the clinical picture. Such a “presenting symptom,” comparable to the “presenting part” in obstetrics, may turn out to be of minor im- portance when we have studied the whole case. But at the outset it has the power to lead us toward right or wrong conclusions in diagnosis, prognosis, and treatment, according as we have or have not learned the art of following it up.
This book is an attempt to study medicine from the point of view of the presenting symptom. 1 hope to show how the complaints of the patient—fragmentary expressions of the underlying disease—should be used as /eads, and how their lead can be followed to the actual seat of the disease.
The plan thus outlined has three parts:
(a) To present a list of the common causes of the symptoms most often complained of by patients, e. g., the causes of pain in the back, of vomiting, or of hematuria.
(6) To classify these causes in the order of their frequency, so far as this is possible.
(Cc) To illustrate them by case-histories in which the present- ing symptom is followed home until a diagnostic problem and its solution are presented.
- THE GROUPING OF REASONABLE POSSIBILITIES
Diagnoses are missed—(a) Usually because physical signs are not recognized; (b) occasionally because we do not think correctly.
This book will not help any one to recognize the signs of disease, but it ought to aid physicians to solve those clinical puzzles wherein the diagnosis is missed because the patient’s disease is not among those
2 Ww
18 DIFFE
ENTIAL DIAGNOSIS
considered and looked for. In other words, correct diagnosis depends upon what enters the doctor’s head as possible, and on what his head does to sift the possibilities after they have entered it, as well as on the direct recognition of signs by physical examination.
To throw open the mind’s door and allow ail disease to enter into consideration each time that we are called to a bedside is foolish in the attempt, and impossible in the performance. Each case should lead us to arrange before the mind’s eye a selected group of reasonably prob- able causes for the symptoms complained of and for the signs discovered. What we select should depend upon the clues furnished us by the patient himself, or by the results of our own examination.
When, for example, a patient pronounces the word “headache,” a group of causes should shoot into the field of attention like the figures on a cash register. Blue lips and finger-nails call up quite another group of ideas. Each clue or combination of clues should come to possess its own set of radiations or “leadings,” determined partly by what we know of anatomy and physiology, partly by the hard knocks of clinical experience.
- ADVANTAGES OF THE PLAN HERE ADOPTED
This way of working into a knowledge of medicine has the advantage of following the course of procedure by which we often question and examine patients in the office or in the clinic. We begin with the chief complaint and work inward and backward to the causes, the organic lesions, the evolution, probable outcome, and rational treatment of the case. Cases do not often come to us systematically arranged like the account of typhoid in a text-book of practice of medicine. They are generally presented to us fron an angle, and with one symptom, often a misleading one, in the foreground. From this point of view we must reason and inquire our way back into the deeper processes and more obscure causes which guide our therapeutic endeavors.
Why do so many practitioners treat symptoms only? Why are their diagnoses and the resulting treatment so full of vagueness, groping, hedging, and “shot-gun” prescriptions?
Because they do not know how to get beyond symptoms. They have not been taught from the point of view of practice—i. ¢., of the presenting symptom. What are the possible causes and linkages of any symptom? Which of them are most probable? By what methods of questioning or of examination can the actwal cause be found? This book aims to put into the physician’s hand the means of answering these questions.
INTRODUCTION 19
I quite realize that the art of forming reasonable hypotheses about a case of disease and then of testing these hypotheses by such experiments as shall establish the correct and nullify the incorrect, is useless unless the methods of physical and chemical diagnosis have been mastered and unless the natural history of all common diseases has been learned by observation and reading. But experience shows that a man may pos- sess a considerable acquaintance with physical diagnosis and with the course of disease, and yet be quite helpless in the presence of a suffering person, simply because he cannot apply his knowledge to this case. He can observe, he can remember, but he cannot constructively think and experiment. Every item of physical or chemical examination is an experiment made to test the soundness of an idea about the case in hand. Skill in thinking and in putting our thoughts to such a test of experiment are not learned either by drill in physical diagnosis or by reading upon the history of disease.
To give such practice in thinking and working one’s way into the mastery of a case of disease, through the intelligent verification of our thoughts by physical examination, is my object in the following chap- ters. They follow the method of case-teaching which I have used for eight years at the Harvard Medical School, applying there a method long employed at the Harvard Law School, and first described by Dr. W. B. Cannon.
4, LIMITS
To keep the book within reasonable limits I have selected 12 symp- toms (see Table of Contents) which are most often complained of by patients. I am well aware that others, such as diarrhea, constipation, loss of weight, paralysis, pallor, edema, purpura, or palpable tumors, might well have been discussed did space permit.
- VULNERABILITY OF ALL DIFFERENTIAL DIAGNOSIS
‘The discussions which here follow each printed case are concerned with differential diagnosis, a very dangerous topic—dangerous to the reputation of physicians for wisdom. It is, I suppose, owing to this danger that so little has been written on differential diagnosis and so much on diagnosis (non-differential). To state the symptoms of typhoid perforation is not difficult. To give a set of rules whereby the condi- tions which simulate typhoid perforation may be excluded is exceedingly difficult. Physicians are very naturally reticent on such matters, slow to commit their thoughts to paper, and very suspicious of any attempt to tabulate their methods of reasoning.
20 DIFFERENTIAL DIAGNOSIS
Yet all diagnosis must become differential before it can be of any use, All recognition of a lesion or a disease involves distinguishing possible sources of error and excluding them by a reasoning process—more or less definite and conscious. To be of any value, then, diagnosis must descend into the arena where it is questioned and assailed, where all sorts of errors and uncertainties arise to unsettle our wisdom. Those differential tables which we all distrust so much are really no more untrustworthy than the diagnoses we make in practice—for every diag- nosis expresses the results obtained by using such a table more or less unconsciously, as we exclude possible errors and alternative diagnoses.
Tam very well aware, therefore, that the differential diagnostic state- ments which fill this book are one and all subject to such limiting phrases as “in most cases,” “asa rule,” etc. This must always be so as long as the list of possible causes or diagnoses which we call to mind when we attack any diagnostic problem is an incomplete list (or possibly an over- inclusive one). To decide which of the known causes of jaundice is the cause of the yellowness of Miss Smith we investigate, by the experiments known as “history,” “physical examination,” and “therapeutic test,” a list of these known causes. But some day we may meet a case in which none of these well-known causes is present. Some new cause, so far unlisted, may, in fact, be at work. There are probably as many fish in the sea as ever came out of it; the unrecognized infections, poisons, and maladjustments are probably as many as those already described in text-books.
All this unconquered territory lies about us, full of hidden dangers to our differential diagnosis—i. e., to all practical diagnosis.
One other limitation must be mentioned. Whenever one sa “The symptoms produced by typhoid (or by peritonitis or by renal stone) are such and such,” one should tacitly add—* provided that it produces any characteristic symptoms at all.” It is certain that the three diseases just mentioned may exist without producing any symp- toms of which the patient is aware. It is probable that this is true of all other diseases. But as we can have no direct dealing with these silent types of disease, we can give them place in the theater of our reasonings only in that outer circle reserved for “possible sources of error,” a great and distinguished company whose presence serves to keep us within the bounds of humility and of scientific caution. '
Meantime we must go on with our work of finding the most prob- able among the known causes and discoverable types of disease.
INTRODUCTION 21
6, OMISSIONS
Some diseases are omitted by choice, others by necessity. The 385 cases which I have selected for study were all seen in private or hospital practice. To prevent the possibility of their recognition by the individ- uals concerned I have changed or omitted certain personal details. In essentials the cases are reproduced as they were observed.
I have chosen no cases in which diagnosis was obvious and none in which it was impossible or dependent chiefly on good luck. To avoid the obvious, I have omitted discussion of such clinical pictures as the following:
Patient of twenty-five, who has had two attacks of rheumatic fever, complains of dyspnea, dropsy, and cough, Examination shows a rapid, irregular, transversely enlarged heart, with a presystolic murmur and thrill at the apex and an accentuated pulmonic second sound. ‘There is evidence of passive congestion of the lungs, liver, legs, and gas- tro-intestinal tract, with dropsy of the serous cavities.
There may be many difficulties in physical examination here, but none in the reasoning processes which lead us to the examination and thence to our conclusions. Obvious maladies, such as pharyngitis, peripheral gangrene, or talipes, have been omitted for the same reason; likewise all those in which diagnosis is made only by incision; e. g., acute pancreatitis, certain breast tumors.
While selecting cases in which diagnosis was difficult, bit not impos- sible, I have tried to choose those in which in the end we could attain a reasonable certainty. Absolute certainty is attainable only as the result of operation or autopsy, and not always then. Hence it is possible that certain of my readers may disagree with the diagnosis finally reached in some cases. This is inevitable in a book of this kind, as it is in actual practice. Book and practice alike can only reflect the existing state of medical knowledge, medical uncertainty, and ignorance. But I sin- cerely hope that my errors may be pointed out by correspondents.
After restricting the field in the way just mentioned, I have tried to exemplify in each chapter, all the diseases which often lead a patient to consult his physician, complaining of the symptom which forms the subject of that chapter. Now and then, however, I have altogether omitted some important disease because I could not find any suitable example of it within my own cases or among those which I had myself studied.
In a few cases certain items have been omitted here because they were likewise omitted in the version of the case given me by the attending physician. My task was fo notice their conspicuous or inconspicuous
22 DIFFERENTIAL DIAGNOSIS
absence, and to act accordingly. It seems justifiable, therefore, to impose
a similar task upon my readers.
- EXPLANATION OF DIAGRAMS AND CHARTS
The book contains figures, tables, diagrams, and charts. The two last need some explanation.
The diagrams, which are introduced in each chapter just before the illustrative cases, represent an attempt (the first that I know of) to esti- mate the relative frequency of the commoner causes for each symptom discussed. This estimate, which can be but approximate, rests upon the following data:
(a) An enumeration of the total number of cases of every disease treated at the Massachusetts General Hospital during the last six years. About 180,000 cases are thus classified according to diagnosis, and the relative frequency of each disease in this material is thus roughly com- puted. But these figures do not give us the relative frequency of any of the symptoms (such as jaundice or headache) studied in this book. Many cases of gall-stones are not jaundiced; hence we cannot directly compare the number of gall-stone cases with the number of cirrhoses (for example), but must estimate the percentage of jaundiced cirrhoses and jaundiced gall-stone disease in each group. This is done by con- sulting—
(b) Statistical articles from the literature in which the percentage occurrence of each symptom in a large series of cases is worked out. Such statistical articles, however, are not common. In Rolleston’s magnificent monograph on the liver almost every statement has a statistical basis, and the wearisome recurrence of phrases like “as a tule,” “not infrequently,” “sometimes,” etc., is replaced by concrete quantitative estimates. But there are not many such books. Hence I have been forced in some instances to compute the percentage occur- rence of a symptom by—
(c) The study of the symptom and of the frequency of its occur- rence in 250 cases of the disease in question; these cases were taken from the more recent records of the Massachusetts General Hospital.
By the methods described under (a), (6), and (c) the length of every line in every diagram has been calculated. Iam well aware that there are numerous sources of error in these calculations. The diagnoses in the Massachusetts General Hospital records may be faulty in some instances, though the large number of cases used tends to minimize such errors. The statistical articles referred to under (6) may be incorrect, and do not often include a very large bulk of cases. Finally, the number of cases
INTRODUCTION 23,
referred to in the calculations under (c) is smaller than I should wish. More important than any of these errors are the absolute omissions which are sure to be discovered among my tables of causes. I hope for much aid from my critics in supplying such missing links. Indeed, I am con- fident that some one will be so indignant at my mistakes that he will at once begin to write a better book on similar lines—a result which I most earnestly desire.
The sources of my information regarding the figures used in the dia- grams are given in Appendix A, p. 743.
The list of causes represented in these gridiron-shaped diagrams is not wholly the same as that exemplified in the illustrative cases. Only the commonest, clearest, and most important causes are drawn in upon the “gridirons.” Still a third group of causes, which do not lend them- selves either to diagrammatic or to detailed illustrative treatment, are mentioned briefly in the introductory section of each chapter. Hence the complete list of causes discussed is to be found—(a) In part in the gridirons; (6) in part in the illustrative cases; (c) in part in the intro- ductory section of each chapter.
The Charts.—Beside the three lines, which represent in the ordinary way the course of temperature, pulse, and respiration, there is a fourth line interwoven with the respiratory curve, and distinguished by the presence of cross striz, like the railroads on a map. This line stands for the twenty-four-hour amount of urine measured in ounces.
Tn the charts the line of this type HHH HHH Hee indicates the amount of urine in ounces, while the line cut by stars, as follows, * ok ** represents the blood-pressure.