History of medical diagnosis

An Egyptian medical textbook, the Edwin Smith Papyrus written by Imhotep (fl. 2630-2611 BC), was the first to apply the method of diagnosis to the treatment of disease.[1]

A Babylonian medical textbook, the Diagnostic Handbook written by Esagil-kin-apli (fl. 1069-1046 BC), introduced the use of empiricism, logic and rationality in the diagnosis of an illness or disease.[2] The book made use of logical rules in combining observed symptoms on the body of a patient with its diagnosis and prognosis.[3] He described the symptoms for many varieties of epilepsy and related ailments along with their diagnosis and prognosis[4] which both played significant roles in the practice of Babylonian medicine.[5]

Predated by Babylonian and Egyptian medicine, traditional Chinese medicine (TCM) was described in an ancient Chinese text, the Yellow Emperor's Inner Canon or Huangdi Neijing which dates to the first[6] or second[7] century BCE. The four diagnostic methods of TCM[8] which are still being practiced today are inspection,[9] listening and smelling,[10] inquiry[11] and palpation.[12]

Over two thousand years ago, Hippocrates recorded the association between disease and heredity. In similar fashion, Pythagoras noted the association between metabolism and heredity (allergy to Fava beans). The medical community, however, has only recently acknowledged the importance of genetics and its relevance to mainstream medicine.

The Arabic physician, Abu al-Qasim al-Zahrawi (Abulcasis), wrote on hematology in his Al-Tasrif (1000). He provided the first description on haemophilia, a hereditary genetic disorder, in which he wrote of an Andalusian family whose males died of bleeding after minor injuries.[13]

The Persian physician, Ibn Sina (Avicenna, 980-1037), in The Canon of Medicine (1025), pioneered the idea of a syndrome in the diagnosis of specific diseases.[14]

the analysis of urine

Physicians used many different techniques to analyze the imbalance of the four humours in the body. Uroscopy was most widely used for diagnosing illness. Physicians would collect patients urine in a flask called “matula”.[15] The matula was specific in shape and had four regions – circulus, superficies, substantia, and fundus – that corresponded to regions of the body. The circulus corresponded to the head; the superficies corresponded to the chest; the substantia corresponded to the abdomen; the fundus corresponded to the reproductive and urinary organs. Urine was inspected based on four criteria: color, consistency, odor, and presence of precipitate.[16] Physicians analyzed the urine for the four criteria and used that to point out where there was an imbalance of the four humours based on the location in the matula.[17] Physicians also examined blood via phlebotomy, they would observe the viscosity and color of the blood as it was draining from the patient and/or contained in a vial. The color and viscosity denoted whether the patient had an acute, major, or chronic disease; which also assisted the physician with the next course of action.[18]

Physicians would also observe a patients pulse by palpation; this technique was performed by carefully noting the rate, power, and tempo of a pulsing artery. By interpreting the pulse of the physician could diagnose the type of fever the patient had.[19] Astrological diagnosis was the least used technique for diagnosing illness. Diagnosis was based on the position of the moon in relation to the constellations, which were associated with different regions of the body (head, arms, chest, etc.).[20] Physicians would diagnose illness with the combined knowledge of zodiac signs and humoral medicine.[21]

In the first half of the 19th century, the well-known British physiologist Marshall Hall emphasized the necessity of maintaining a close relationship between the theory and practice in medicine.[22] He wrote On diagnosis (1817) and The Principles of Diagnosis (1834).

The ideals of William Osler, who transformed the practice of medicine in the early 1900s, were based on the principles of the diagnosis and treatment of disease. According to Osler, the functions of a physician were to be able to identify disease and its manifestations and to understand its mechanisms and how it may be prevented or cured. For his medical students he believed that the best textbook was the patient himself—analysis of morbid anatomy and pathology were the keys. The Oslerian ideal continues today as the basis of the doctor's strategy is, "What disease does this patient have, and what is the best way for treatment?" The emphasis is on the classification of the disease in order to use the remedies available for its effects to be reversed or ameliorated. The human being in question is representative of a class of people with this type of disease; this person's biological individuality is not given any great weight.

The successor to William Osler as Regius Professor at Oxford was Archibald Garrod. Garrod echoed the observations of his Greek counterparts of two millennia ago, ...our chemical individualities are due to our chemical merits as well as our chemical shortcomings; and it is more nearly true to say that the factors which confer upon us our predispositions to and immunities from various mishaps which are spoken of as diseases, are inherent in our very chemical structure; and even in the molecular groupings which confer upon us our individualities, and which went into the making of the chromosomes from which we sprang. Because Garrod practiced in the early 1900s, well before the knowledge of DNA encoding genes that in turn encoded proteins responsible for bodily structure and functions were discovered, it took some time before medicine could fully appreciate the fundamental importance of his concept of diagnosis.

Whereas Osler laid the founding principles by which medicine should be practiced, Garrod placed these principles in a greater context of a chemical individuality that is inherited and is subject to the mechanisms of evolutionary selection. The Oslerian ideal of medical practice continues to dominate medical philosophy today. The patient is a collective of symptoms to be characterized and analyzed algorithmically in order to draw a diagnosis and subsequently produce a strategy of treatment. Medicine is about problems based solutions. In keeping with this philosophy, today's pathology reports provide a momentary snapshot of the patient's biochemical profile, highlighting the end result of the disease process.

Garrod's conception of biological individuality was confirmed with the advent of the sequencing of the human genome. Finally the subtle relationship between inheritance, individuality and environment became apparent via the variations detected in DNA. In each patient's DNA lies a script for how their bodies will change and become ill as well as how they will handle the assaults of the environment from the beginning of their life to its end. It is hoped that by knowing a patient's genes that the biological strengths and weaknesses in respect to these assaults will be revealed and disease processes can be predicted before they have the opportunity to manifest. Although knowledge in this area is far from complete, there are already medical interventions based on this. More importantly, the physician, forewarned with this knowledge can guide the patient towards appropriate lifestyle changes to anticipate and mitigate disease processes.