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-

General Part

Chapter 4. General Methodology of Diagnosis

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.