Clinical Skills: The Detection Of Diseased Organs
Dr. P. Warren
Professor, Faculty of Medicine, University of Manitoba
What a patient experiences, their symptoms, takes them to the physician. The first role of that physician is to diagnose what is wrong before considering the prognosis and providing treatment. Accurate diagnosis is most dependent on the history obtained and physicians become skilled at questioning their patients. But at the same time the physician uses the senses, sight, touch, hearing, smell and in the past even taste to identify abnormalities in the patient.
The Grecian-Roman Era
Hippocrates had developed observation of the patient and the progress of their disease as the science of medicine. He described the appearance of the patient, felt their temperature, smelled their vomit. Although doctors became particularly skilled at examining the lumps, cuts and breaks of the body, "external" medicine, they rarely tried to examine the inside of the body. There were exceptions such as Hippocrates shook the patient with pleurisy to detect a splash when there was fluid in the pleural space; the Hippocratic Succussion Splash.
Observations are considered to be more scientific if measurement of them can be made. In Alexandria, Herophilus (300 BC) would feel the pulse and count it using a water clock. Galen (129 AD) relied heavily on touch, palpation for diagnosis an essential skill for assessing wounds and injuries. Galen had practiced sports medicine with the gladiators. He would describe the general appearance of the patient but also tasted sweat for jaundice and listen to the rumbling abdomen. Galen learnt much from feeling the pulse, which he did in both wrists using three fingers for it, was thought to reveal disorders of the organs of the body - much more than we can. There is much in common with what was understood by him from the pulse and Chinese medicine - perhaps a spread of ideas along the Silk Road. They did not measure the pulse but where said to learn many things from its feel.
The Renaissance: Early Physiology
In 1583 a medical student was bored by a sermon and observed that the swinging of the altar lamp was unvarying and that this could be used to measure time. The student was Galileo (1564-1642) who as we know gave up medicine for astronomy fame and ill fortune at the hands of the Catholic Church. Galileo's pendulum clock was adapted by Sanctorius (1620 AD) to measure the pulse with what he called the pulsilogium. Sanctorius (1561-1636) was a major physiologist for he used a thermometer for temperature and a weighing chair to measure the intake and output of food and fluid. But since there was little understanding of the function of the body since the Hippocratic Galenic belief in humours and the spirits of the body these measurements did not advance medicine. This was to change with the Italian Renaissance and the lessons of the anatomists who identified the true state of the organs of the body and set the scene for understanding their function.
The work of the Englishman William Harvey (1575-1657) who had studied in Italy described the circulation of the blood but added nothing to the diagnosis of disease. He thought the heart distributed the humours and spirits. In 1707, Sir John Floyer (1649-1743) introduced the pulse watch and thought it of more value than Harvey's work. Physicians began to count the pulse regularly and would note it in various ways. In 1731, a new dimension was added to the measurement of the body with the work of Stephen Hales (1677-1771) who studied the pressure in arteries and veins. He would insert a cannula into the vessels and measure the height of the column of blood - the blood pressure. But these advances were relatively meaningless until the understanding that diseases were often abnormalities of the structure or function of organs.
In 1761, Auenbrugger (1722-1809) who had observed his father, an innkeeper, assess how much wine was left in barrels by knocking on them introduced percussion of the chest to identify if it contained excess fluid- a pleural effusion. He wrote:
I present the reader with a new sign, which I have discovered for detecting diseases of the chest, This consists in the percussion of the human thorax, whereby according to the character of the particular sounds thence elicited, an opinion is formed of the internal state of that cavity.
But Auenbrugger's work attracted little attention for the stage had not been set for the organ-based concept of disease. This occurred in 1761 by the octogenarian Morgagni (1682-1771) publishing his observations of pathology that he had made during his lifetime of dissections. The autopsy of patients and the lessons learnt from the abnormalities in the structures of the body so revealed became the foundation of modern medicine.
Paris: The Routine of Physical Examination
Clinicians attempted to detect these diseases inside their patients. Corvisart, physician to Napoleon, (1755-1821) applied Auenbrugger's work. He used percussion to diagnose heart disease and Corvisart's lectures were recorded and published thanks to the work of one of his pupils. In the book's preface he stated "the end truly useful, is to study on the living and diseased man, the characteristics peculiar to lesions of the different organs". In 1808 Corvisart published a translation of Auenbrugger's work and percussion entered regular clinical practice. This encouraged Parisian physicians to use the other senses and in particular they began to palpate the body and listen to the sounds of the heart by applying their ear directly to the chest.
1819 was a seminal date in medicine with the publication by the Parisian Laennec of "L'auscultation mediate". Laennec (1781-1826) who made major studies of the pathology of lung and heart disease, correlated this with clinical observations. He described his discovery thus:
In 1816, I was consulted by a young woman labouring under general symptoms of diseased heart, and in whose case percussion and the application of the hand were of little avail on account of a great degree of fatness. The other method (direct auscultation) being rendered inadmissible by the age and sex of the patient, I happened to recollect a well-known fact in acoustics, and fancied, at the same time, that it might be turned to some use on the present occasion... I rolled a quire of paper into a sort of cylinder and applied one end to my ear and the other over the heart.
Thus was borne the instrument that Laennec named the stethoscope.
Laennec studied the correlation of what he heard with what he subsequently found at post mortem and so learnt to visualize the abnormalities in the heart and lungs. Internal medicine was born for now the diseases of inside the body could be identified.
The stethoscope was soon adopted by the many young physicians who had studied in Paris that at that time was the place to go for postgraduate studies. Thomas Hodgkin of Hodgkin's Disease brought it to London and Pierre Beaubien brought it to Montreal in 1822. Studies of animal models and isolated organs made the art of auscultation firmly based on scientific observation. Changes in breath sounds would detect tuberculosis while heart murmurs would reveal the damage of rheumatic fever to the heart valves. But the experience and the ability of the physician determined the accuracy of the diagnosis and variability between patients and between physicians was a problem.
Meanwhile measurement in physiology was advancing. Lavoisier (1743-94) aided in his experiments by his wife Marie had discovered oxygen and studied its uptake in man under different conditions. Humphrey Davy (1778-1829) measured the volume of his own lungs using hydrogen. In 1844, Hutchinson published his studies of the size of a maximum breath in over 1200 men using the spirometer; a measurement he called the Vital Capacity. He showed that reductions in vital capacity would detect tuberculosis before signs of it were revealed with the stethoscope. Hutchinson pointed out that measurements of the lungs were not only more sensitive but more importantly "it permitted doctors, whether able or inept, to make accurate judgements. No exquisite sensory training was required to obtain or understand the data". The certainty of measurement is to be favoured over the art. It is of historical interest that Hutchinson published no measurements on women - this was not another example of male physicians ignoring the health of women. It was the practical fact that the fashions of that period with tight lacing of women's bodies produced artificially low vital capacities.
Measurement of the circulation was developed. In 1896, Riva Rocci (1863-1936) introduced the modern sphygmomanometer - a cuff of a pneumatic band attached to a mercury manometer. In 1906, Korotkoff identified the value of listening to the arterial sounds as the cuff was inflated and deflated.
At the end of the nineteenth century came the greatest advance in the physician's ability to see inside the body with the discovery of x-rays by Roentgen (1845-1923). He was experimenting as a physicist with rays and detected some that would penetrate solid material and the "shadow" created recorded on photographic film. Amongst other objects he x-rayed his wife's hand on December 22, 1895, and revealed the structure of the bones. Very quickly the news of his discovery spread around the world and in many locations the apparatus was made and used. The x-ray was first used for medico-legal evidence in Montreal at a trial on February 7, 1896 to find a bullet in a leg.
In the twentieth century x-rays were used for chest disease and by administration of barium for the gut and the injection of dyes more and more organs revealed. Sound waves, with the experience of sonar for detection of submarines in the war, were harnessed through ultra-sound to depict body structures. In due course the further application of physics has provided the Computerized Axial Tomographic (CAT) scan and Magnetic Resonance Imaging (MRI).
In 1901, Einthoven (1860-1927) recorded the electrical function of the heart and the electrocardiogram was born. The electrical impulses could be sent a distance and so physicians did not have to be present to learn much information about their patient.
The science of physical examination, which as a skill is viewed as the art of medicine, has been mainly replaced by the technology of imaging and measurements. However both are scientific based on principles of physics although at different levels of sophistication. Today ultrasound has replaced percussion to a large extent for accurate definition of effusions. Science and measurement enhances the certainty and reproducibility of the observation and improves the accuracy of diagnosis.