CHAPTER I I METHOD IN DIAGNOSIS
In this manual an attempt is made to study the process of diagnosis, and thereby to put the reader in possession of linowledge which will enable him to determine the nature of a patient's ailment. The process of diaf/iiosis rests, firstly, upon accurate observation of the facts of the case, and, secondly, upon their correct interpretation. The facts should, as far as possible, be observed by the surgeon him- self, and accuracy in observation must be his first aim. There are three particular points to be re- membered in the appreciation of facts.
The first of these is the recognition of the signifi- cance of each separate observation. For instance, the sign of fluctuation does not necessarily signify the presence of pus, nor retraction of the nipple the existence of a mammary scirrhus tumour. Fluctuation merely indicates the presence of fluid under certain special physical conditions, but it tells nothing whatever of the origin and nature of the fluid. A retracted nipple signifies a disproportion in the length of the galactophorous ducts, but it tells nothing of the
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2 SURGICAL DIAGNOSIS [chap.
cause of this disproportion. It is all-important that students should strenuously cultivate the habit of looking _ behind symptoms and signs to their physical or physiological significance, and not regard them as so many ultimate facts : they should ask themselves why a certain combination of symptoms necessitates or renders highly probable a particular diagnosis.
The second point to remember is that data vary very widely in value ; care and experience are needed to form a right estimate of their value. Failure in this respect is one of the common causes of mis- taken diagnosis. Positive data are of more value than negative ; objective signs of disease are of more value than subjective ; all data vary in value with the care and competence of the observer. But we cannot afford to reject altogether negative and subjective data, or refuse to accept observa- tions made by unskilled observers.
The third point to bear in mind is that certain facts are of conclusive value in diagnosis, and one of the aims of clinical and pathological study is to add to the number of such. Thus, the evidence afforded by X-rays in fracture or dislocation is of this con- clusive kind. Again, the detection of the Spironema pallidum {Spirochceta pallida) in the discharge from a sore on the genitals establishes the nature of the sore, and renders the clinical characters of the lesion of no diagnostic importance. Many of these conclusive facts are only obtained by the help of special laboratory or other assistance, which may not in all cases be available ; it is of the utmost importance, therefore, that the student should develop his powers of purely clinical diagnosis, using these special aids as checks upon his own observations, and not as excuses for slipshod or incomplete examination.
ij FAMILY HISTORY S
Of late years surgical treatment has become very largely operative, and in the course of an operation the nature of a case is often cleared up much more completely than was possible beforehand. Although clinical diagnosis must often come short of the demonstration afiorded by an operation, this is no justification for neglect of the clinical means of diagnosis. An accurate diagnosis will often obviate a useless operation, and nothing facilitates an opera- tion more than an exact knowledge of the conditions to be dealt with.
A diagnosis, to be complete, should include the recognition of, first, the anatomical features of the local lesion ; then, its physiological or pathological characteristics ; and lastly, the constitutional change either leading to or resulting from the local lesion. For example, take the case of an enlarged gland in the groin. The first step in the diagnosis is to de- termine that it is an enlarged gland, and not a hernia, a varix, or a fatty tumour, etc. This must be followed by an inquiry into the nature and cause of the enlargement, whether inflammatory or neo- plastic ; if inflammatory, the nature and source of the infection, and if neoplastic, whether primary or secondary. Finally, it must be ascertained how far the general system is implicated, whether primarily or secondarily, as by fever, exhaustion, anasmia, etc.
Apart from the clinical data afforded by the examination of the patient, the progress of his affection, and the effect of treatment, valuable help in the diagnosis is derived from a consideration of the family history, personal history, and history of the cause or first onset. ^
Family history.— In some instances we seem justified in assigning to heredity great importance, HI others its influence is wholly unrecognized, and
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between these two extremes we meet with all possible degrees of difference.
Of those affections of surgical importance in the parents which are justly believed to influence dis- ease in their offspring, the most important is syphilis. There is no doubt that syphilis is inherited, but it is no less certain that all the children of syphiHtic parents are not themselves the subjects of syphilis. In general, the liability to iuheritance is greater, the shorter the interval between the infection of the parents and the birth of the children. To ascertain that the patient is the subject of inherited syphilis is of the utmost importance ; for not only may it at once determine diagnosis, but it will exert a distinct influence upon treatment, and in very many instances form the sole guide to the management of the case.
Haemopliilia is also an important hereditary affec- tion, and, where this exists in a family, evidence of it is usually obtained, as the repeated and often fatal hsemorrhages are facts which strongly impress the laity. It must be remembered that inquiry is to be mainly directed to the male members of the family, as it affects them only, although it is transmitted through the females. The faulty metab- olism manifested ia gout is often inherited, as is also the tendency to congenital deformities. Acholuric jaundice is another disease, now surgical in cliaracter, which is definitely inherited.
Tuberculosis, whether of lungs, bones, or glands, is not inherited, but a predisposition to tlie disease certainly is. Evidence of this predisposition to tubercle in a family is usually readily obtained, for ])hthisis, diseases of bones and joints, ]n]nis, and lymj)hatic nUiiiduIar enlargements are too obvious, too chronic, and too serious in their results to be overlooked or forgotten.
I] HISTOEY OF THE AFFECTION
It is a common belief among tlie laity that a similar predisposition to cancer may be inherited, but real evidence for this is wanting, and a family history never influences the diagnosis of the nature of a tumour.
Personal history. — The points in the personal history of the patient which assist in the diagnosis are : 1, Race, e.g. the greater frequency of diabetes and hfemophilia among the Jews. 2, Age : many conditions can only occur when the skeleton is im- mature, e.g. separation of epiphyses, while others, such as rodent ulcer, only after the period of full maturity has arrived. 3, Sex : apart from the diseases of the distinctive sexual organs, there are certain diseases which are more common in one sex than in the other, e.g. hsemophilia in the male, mov- able kidney in the female. 4, Civil state, whether single, married, or widowed ; if married, whether nulliparous or parous. .5, Habits, particularly as to the consumption of alcohol and tobacco, and lack or ex-cess of exercise. 6, Occwpalion : for example, working in phosphorus, mercury, lead, parafBn, tar, the handling of hides or horses, exposure to wet and cold or to severe strain, kneeling, constant standing, mining, and contact with soot. 7, Residence abroad, by exposing the patient to special infections, e.g. schistosomiasis (bilharziosis) in Egypt, hydatid disease in Australia, filariasis in tropical Africa. 8, Previous diseases : the common afEections liable to be followed by sequelte of surgical importance are venereal diseases, enteric, dysentery, scarlet fever, measles, and phthisis.
History o£ the alfeetion. — Plaving obtained an account of the supposed origin of the affection, note carefully its exact course, and the order, mode, and tunc of development of any changes in it, tooelher
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SURGICAL DIAGNOSIS [chap.
with the effects of any treatment that may have been adopted. And first comes the influence of injury. A large class of cases, such as wounds, fractures, sprains, are commonly described as " injuries." But, among diseases, injury plays an important part by admitting infective organisms to the tissues, and also by converting tissues into a suitable nidus for the growth of organisms, and so localizing infective diseases. There is reason to think that injury plays some part as an exciting cause of the growth of tumours. An injury is often the means of attract- ing the patient's attention to a pre-existing morbid state. A blow alleged to be the exciting cause of a tumour of the breast may merely have led a patient to make an examination of the part and detect a lump which, not being painful or prominent, had previously escaped observation. The only way of avoiding this error is to ascertain as accurately as possible the succession of events and the time- relation of the injury and any signs or symptoms of disease.
The mode of progress of the disease may be an important factor in diagnosis, for while any disease may steadily advance, only certain forms are capable of spontaneous recession, e.g. a bruise or an inflamed gland ; or of an intermittent or remittent course, for instance appendicitis, hernia, and movable kidney. The mere duration of an affection may exclude some forms of disease, as for instance malignant growths and acute inflammation.
The sequence of symptoms is sometimes of import- ance, as, for example, where renal colic is followed by signs of vesical calculus, or where the apparent reduction of a hernia is attended with no relief to, but rather an increase in, the severity of the signs of strangulation of the bowel. The relative intensity
ij METHODS OF DIAGNOSIS
7
of various symptoms may aid iu the diaguosis ; thus, the absence of paiu may exclude acute inflam- mation, or the frequency and amount of vesical ha3morrhage may clearly connect any other urinary symptoms with the presence of a tumour in the bladder. Lastly, the time-relation of any constitu- tional state, such as antemia, wasting, jaundice, or cachexia, may indicate whether it is the cause or the result of some local morbid state.
In reference to the results of treatment, special significance is to be attached to the influence of general tonic treatment, of rest, of counter-irritation, of surgical operations, and of the usual antisyphilitic remedies.
The general method of diagnosis varies with different surgeons : some prefer first to obtain a complete history of the case, and then to make their examination of the lesions presented ; while others first make their examination, and then in- vestigate the history of the case. Eor beginners, however, the former and more laborious plan is the better, lest important points be overlooked ; and it is only safe to practise the more direct method when clinical experience has developed the instinct which enables a surgeon to elicit just those points in the history of a case that have a real bearing upon the diagnosis.
The particular methods of diagnosis vary with the general character of the case, and with the locality of the affection. We shall try to indicate these in their proper places, and would here only mention that there are many plans which may be adopted, and possibly with equal advantage.
Nothing will conduce more to correct diagnosis than the practice of note-taking and of commlttinrr to writing the diaguosis of a case and the reasons
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SURGICAL DIAGNOSIS [chap.
to be urged in support of it. We would venture to press this point upon the attention of students, and to assure them that any time so spent will yield them a full reward in the readiness, confidence, and accuracy in diagnosis it will produce.
The results of our examination of the patient are the most important facts for purposes of diagnosis ; for the evidence so obtained is mostly, if not wholly, objective, and is also skilled evidence. To show how the data thus obtained, combined with others, enable us to diagnose various morbid states is the chief purpose of the following chapters.
The examination of the patient should in all cases be as complete and careful as possible, no point being omitted because of its apparent want of bear- ing upon the case. The interest and practical im- portance of local lesions is so great that there is a grave danger lest in our view of the disease we lose sight of the subject of it, and fail to complete the local examination by a comprehensive survey of the patient as whole.
The examma'tion should be systematic, precise, and purposive ; the investigation of symptoms should be conducted in some regular order, and each question, each manipulation, each part of the examination, should have some definite object. To conduct an examination in this way not only promotes accuracy of diagnosis, but also tends to facilitate and expedite it, because it necessitates the surgeon using his mind and his senses together. Its value is often con- spicuously seen in the way two men will examme a tumour : one of them in a few moments will have learnt all its characters, while the other, after a more prolonged examination, will have ascertained little or nothing about it, and will be unable to speak definitely and with assurance as to its nature ; and
I] EXAMINATION OF PATIENT 9
this may be not so much from want of absolute knowledge as from ineptitude and the want of a definite aim and purpose in the examination.
Students from the first should form the habit of taking single precise observations, and not trust to mere repetition for ensuring accuracy.
Whenever the results of examination can be stated in numbers, this should be done, as in the case of the temperature, pulse, respiration, measure- ments of all kinds, number of fits, fi-equency of micturition, etc.
Care is required in making even the simplest observation, such, for instance, as counting the pulse, or measuring the length of a Umb. Where a single observation leaves a doubt upon the observer's mind it must be cleared up by repeating the observation, but we should like to insist upon the great im- portance of forming the habit of relying upon a single observation. It is only too common to see the manipulation for the detection of fluctuation repeated several times before the observer is sure of the result ; similarly, a patient with a scrotal tumour is made to cough several times before it is decided whether the act causes an impulse in the swelling or not; and it would be easy to multiply similar examples.
As far as possible, objective phenomena must be observed by the surgeon himself. For instance, a patient's statement that he cannot swallow must not be accepted until his attempt and failure to do it have been seen ; in this, as in many Uke cases, pain in an act is often spoken of by the sufferer as in- ability to perform it. Subjective symptoms must be separately investigated and their true value carefully appraised.
Further, in an increasing variety of morbid con-
10 SURGICAL DIAGNOSIS
ditions help is afEorded by X-ray examination, chemical, cytological, or bacteriological investiga- tion. And the examination is not to be considered complete until the appropriate investigations have been made. The results must be interpreted in the light of the clinical examination in arriving at the final diagnosis.