Planning Diagnostic Examination

Two types of diagnostic examination of the patient are distinguished. One of them consists in the following. As suggested by the main or a more vivid symptom, e.g. cardiac pain, jaundice, cough, vomiting, etc., the physician examines the corresponding organs or functions. He arrives at a diagnosis from the symptom through a concise additional examination. For example, if a patient complains of right iliac pain, and palpation in this region is painful a diagnosis of appendicitis may be established (provided other signs are revealed). This method is often used for a quick diagnosis in emergency cases. But this method is effective only in simple cases and is fraught with danger of erroneous diagnosis, because the patient's general condition and all the systems of his body are not examined thoroughly. Moreover, the examination is carried out without any plan and method and the diagnosis is thus incomplete and abstract.

The other approach can be called methodical and is more complicated. All the organs and systems of the patient are examined following a certain plan. Clinical anatomy (pathological anatomy included), physiology, con­stitution (including the body make-up, functional performance, type of the nervous system, reactivity, which is important for individual diag­nosis), separate signs of the disease are studied, i.e. a physician car­ries out an analysis the purpose of which is to assess the condition of the body as a whole. This can be done by the synthesis of the findings. The study of the patient is not, however, completed at this stage. Additio­nal laboratory and instrumental studies should be carried out on the basis of the discovered symptom or syndrome in order to verify the lesion or the affected organ and to reveal the essence of the pathology, the symptoms are compared to establish connections that may exist bet­ween them, and finally all findings are put together to arrive at a final diagnosis.

Even if a diagnosis can be established at first sight (e.g. exophthalmic goitre, a wound, erysipelas, heart defect, etc.), a methodical study of the patient is also necessary. This complicated examination should end by establishing a diagnosis, not only a correct but also detailed enough in order to suggest the proper choice of therapy.

It should be noted that the diagnosis of the disease and of the patient cannot be regarded as a constant formula since it changes with the develop­ment of the disease. Under the effect of treatment or during development of complications, the condition of the patient can change markedly, and the diagnosis and prognosis will change accordingly. The diagnostic study of the patient's condition is thus continued during the entire period of

clinical observation and treatment. This is the diagnosis of the course of the disease and also verification of the initial diagnosis.

The diagnostication process can be divided schematically into iden­tification of the disease and the study of the patient during the course of the treatment. The diagnostic conclusion covering the entire period of observation and treatment is summarized in epicrisis.

Special Features of Diagnostic Examination

The first and prerequisite condition to identify a disease and assess the condition of the patient is the knowledge of medical subjects and special pathology, i.e. nosological forms of the diseases. But clinical pictures of various diseases are described in textbooks only schematically. Clinical experience shows that actual cases would usually differ from these schematic descriptions since the origin, course and clinical manifestations of the disease strongly depend on the condition of the patient and the environment.

An important diagnostic factor is that the human body responds to various stimuli or aetiological factors by a limited number of general reactions, e.g. the normal response to most infections is fever, to local irritation it responds by inflammation, etc. Moreover, the general reaction of the body to various uncommon stimuli is often the same, especially at the onset of the disease. Clinical signs themselves are not therefore sufficient for the determination of the concrete aetiological factor or for the discovery of specific changes.

Several groups of diseases are distinguished according to various responses of the body to the pathogenic cause or injury. When establishing a diagnosis, the physician first of all decides to what group of the diseases can this particular affection be attributed. In other words, the physician first decides if a particular case is an infectious disease, upset metabolism, inflam­matory process, newgrowth, allergic disease, autoallergy, upset neurohumoral regulation, etc.

Another difficulty is that various combinations of pathological processes are encountered in various patients. And finally, even in seemingly typical cases, there are always special features that do not occur in other patients.

The necessary condition to identify a disease is the professional skill of the physician to apply his knowledge in the varied and changeable conditions of life. The professional skill is acquired with experience in solving diagnostic problems. An independent practitioner is form­ed through mastering the method by which the acquired knowledge can be applied to practical cases. Correctness of the diagnosis largely depends on this skill.

Selection of a particular scientific method depends mainly on the object of study, its pur-Pose, and the working conditions. This explains the difference between diagnostic methods and the methods that are used in other sciences. The diagnostic study is aimed at understan­ding of the patient's condition in order to change it, i.e. at determining the disease as a phenomenon that should be removed. The study should not be limited to finding the gene­ral and typical features (which is common for all theoretical sciences); the physician should direct his studies and thinking to understand any particular case which differs from all simi-'ar cases. This is the necessary condition for carrying out his objectives: prophylaxis and treatment.

An important feature of the object of study, i.e. of man, is its complexity with respect to structure and function and also with respect to connections and interactions with the environ-^ment (morphological, physiological, psychic, social features). This explains the necessity of ^Us'ng many methods. The number of methods that a physician uses to examine the patient is

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greater than the number of methods used by representatives of other sciences. The physician uses not only medical methods but those employed in other branches of science, from inquiry by questioning, chemical, physiological, biological and other methods, to very complicated and precise techniques such as electrocardiography, X-ray examination, and others.

This great variety of methods depends not only on the extreme complexity of the object of studies. It is also explained by insufficiency of the methods for complete medical understanding and by the fact that one method cannot be applied to all cases. Moreover, in some cases a certain method cannot be applied without injuring the patient. Medical examina­tion should by no means do any harm to the patient. The physician therefore has to obtain the necessary information by indirect methods and speculations (e.g. incompetence of the heart valves can be determined by percussion, auscultation, type of the pulse, etc.). These dif­ficulties account for diagnostic errors.

Finally, it should be remembered that a physician may have little time to establish a full diagnosis in urgent cases when he has to act immediately to save the patient.

These are the working conditions in which the physician should do his best to apply effi­ciently scientific methods.

Diagnostic Observation and Examination

Scientific studies (diagnostic studies included) begin with observation and are based on experience. Observation is actually an active perception of phenomena substantiated by a purpose which directs the attention of the observer to this or that aspect of the phenomenon. In an exact meaning of this word, observation is a direct perception of natural phenomena (as distinct from experiment where the observed phenomena are modified or induced by the observer).

Observation principles. The diagnostic study begins with decomposi­tion of a whole into component parts, i.e. from the study of simpler parts (analysis). The physician observes the patient by studying his systems and organs in a certain sequence. Observation is thus the first step in the study of the patient (analysis) so that the findings could be synthesized at the next stage of diagnostication. It other words, a whole will be composed from parts that were preliminarily examined separately. It follows that observa­tion provides the elements for construction of diagnosis. Since disease is a combination of affections and certain reactions of the body, it is evident that the visible signs of the disease, the symptoms, are not the disease itself. There are other symptoms that are hidden from the observer and should be revealed. On the other hand, it should be remembered that the symptom of the disease is its external sign which cannot be regarded as a separate phenomenon, existing apart from the pathological process.

The first rules of scientific observation are reliability and accuracy, in both quantitative and qualitative aspects; the second requirement is com­pleteness and comprehensiveness of observations in all their details, and finally, the requisite condition is orderly, systematic and methodic observa­tion along with classification and comparison of the observed phenomena.

Comparison of the data obtained consists in consideration of common and different features of two facts, one of which is the reference against which the other is compared.

Medical examination is not limited by observation alone; it also in­cludes some elements of experiment. By experiment we understand ar­tificially induced changes occurring in the patient's body by giving him, for example, tuberculin (Pirquet test), or special "loads" by which functional disorders can be revealed. Experiment requires a special predetermined idea and reveals the existence of certain connections between the observed phenomena. A limiting factor of the experiment is damage that might be inflicted to the patient. Experiments are therefore rarely used in clinic. But it should be remembered that only experiment can give a complete picture of the functional state and pathogenic connections between processes oc­curring in the patient. It should also be remembered that all phenomena oc­curring in the body are very complicated and interdependent and the results of the experiment should therefore be interpreted very thoughtfully.

The following conditions are requisite for a successful diagnostic obser­vation. 1. Sufficient skill of clinical observation which is decisive for reliability and accuracy of the data obtained. 2. Accurate knowledge of all symptoms. 3. Comparison of the corresponding indices in norm and pathology. This requires adequate knowledge of anatomy, physiology, and the human body on the whole. This enables the physician to decide definitely whether a given phenomenon is a pathological symptom or a sign of a disease. Comparison can be made on the patient himself, e.g. com­parison of the structure and function of symmetrical joints. 4. Determining the degree of probability of this or that disease. First considered should be the probability of a more dangerous or common, or an epidemic disease (e.g. influenza); the probability of endemic disease should also be con­sidered in certain geographical zones; the season is essential for the in­cidence of some infectious diseases, for relapses of gastric ulcer; patient's age is another important factor (diseases of childhood, diseases occurring mostly in old patients, etc.). Sex, occupation, modus vivendi, constitution, and heredity are important in the sense of the predisposition of the patient to this or that disease. 5. Conditions and organization of medical examina­tions and confidence of the patient in his doctor are other important fac­tors.

Accuracy and reliability of medical observation depend on (a) use of special tools and apparatus and also accurate recording of the changes oc­curring during the course of observation. The knowledge of the degree of accuracy and of the error limits for each method are very important; (b) the ^rule of double and triple verification of the symptom observed; the rule consists in that a given symptom, sign, or any finding are repeatedly check-

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ed by various methods (e.g. the lower border of the stomach can be deter-1 mined by percussion, palpation, and percussive palpation; the gallop rhythm is determined by auscultation, palpation, and phonocardiography, etc.). Coincidence of data obtained by various methods ensures accuracy and reliability in assessment of a given symptom; (c) relationships between the discovered symptom and other related (casually dependent) phenomena which strengthen the probability of accurate observations (like detalization of the symptom). Abstractly stated symptom (e.g. pain in the abdomen) is not important diagnostically in itself. The picture is quite different if the intensity, localization and character of this pain, and the accompanying signs can be determined as well. Concretization of the symptom gives suffi­cient material for a correct diagnosis.

Completeness of observation cannot always be ensured because the clinical forms and picture of a disease vary with time (under the influence of the therapy in particular). Medical observation is thus a continuous pro­cess that lasts for the entire time of contact between the physician and the patient. It is especially difficult to apply the "necessary and sufficient" principle to emergency cases where the grave condition of the patient im­poses limitations to examination procedures, but requires an urgent deci­sion. Profound knowledge and vast experience can only help in such cases.

In grave cases, and in conditions of limited possibilities, the first rule that should be followed by the physician in his observations is the examina­tion of vitally important organs. This is necessary to assess the degree of danger to the patient's life. Prognostic evaluation is first of all required. Next the disease should be diagnosed, because the first task of the physi­cian is to save the patient (which is sometimes possible without a detailed diagnosis, for example in shock, coma, acute abdomen, uraemia, etc.). Here the purpose of medical examination is to assess the gravity of the pa­tient's condition and to give the appropriate treatment. This is the first and preliminary measure that should be followed by treatment based on a more detailed diagnosis.

A complete observation is only possible with a follow-up observation of symptoms and determination of the direction in which a given pathology develops since otherwise clinical observation is useless for the diagnostic and therapeutic purposes. Despite the great multitude of methods available observation is never complete. The cause of possible error is the absence of system in observations and erroneous interpretation of findings or unawareness of their clinical importance. Absence of adequate knowledge and experience can be the cause of underestimation of some important observation methods and overestimation of others. Moreover, accumula­tion of facts and symptoms without proper synthesis of the collected data is another factor that can give a diagnostic error.