PART 1Introduction to Clinical MedicineC H A P T E R 1The Practice of MedicineThe Editors_ THE MODERN-DAY PHYSICIANNo greater opportunity, responsibility, or obligation can fall to thelot of a human being than to become a physician. In the care of thesuffering, [the physician] needs technical skill, scientific knowledge,and human understanding. Tact, sympathy, and understandingare expected of the physician, for the patient is no mere collectionof symptoms, signs, disordered functions, damaged organs, anddisturbed emotions. [The patient] is human, fearful, and hopeful,seeking relief, help, and reassurance . Harrisons Principles of Internal Medicine , 1950The practice of medicine has changed in significant ways since thefirst edition of this book appeared more than 60 years ago. Theadvent of molecular genetics, molecular biology, and molecularpathophysiology, sophisticated new imaging techniques, andadvances in bioinformatics and information technology havecontributed to an explosion of scientific information that has fundamentallychanged the way physicians define, diagnose, treat, andprevent disease. This growth of scientific knowledge is ongoing andaccelerating.The widespread use of electronic medical records and the Internethave altered the way doctors practice medicine and exchange information.As todays physician struggles to integrate copious amountsof scientific knowledge into everyday practice, it is important toremember that the ultimate goal of medicine is to prevent diseaseand treat sick patients. Despite more than 60 years of scientificadvances since the first edition of this text, it is critical to underscorethat cultivating the intimate relationship between physician andpatient still lies at the heart of successful patient care.The science and art of medicineDeductive reasoning and applied technology form the foundationfor the solution to many clinical problems. Spectacular advances inbiochemistry, cell biology, and genomics, coupled with newly developedimaging techniques, allow access to the innermost parts of thecell and provide a window to the most remote recesses of the body.Revelations about the nature of genes and single cells have openedthe portal for formulating a new molecular basis for the physiology ofsystems. Increasingly, physicians are learning how subtle changes inmany different genes can affect the function of cells and organisms.Researchers are beginning to decipher the complex mechanisms bywhich genes are regulated. Doctors have developed a new appreciationof the role of stem cells in normal tissue function and in thedevelopment of cancer, degenerative disease, and other disorders,as well as their emerging role in the treatment of certain diseases.The knowledge gleaned from the science of medicine has alreadyimproved and undoubtedly will further improve physiciansunderstanding of complex disease processes and provide newapproaches to disease treatment and prevention. Yet, skill in themost sophisticated application of laboratory technology and in theuse of the latest therapeutic modality alone does not make a goodphysician.When a patient poses challenging clinical problems, an effectivephysician must be able to identify the crucial elements in a complexhistory and physical examination; order the appropriate laboratory,imaging, and diagnostic tests; and extract the key results fromthe crowded computer printouts of data to determine whether totreat or to watch. Deciding whether a clinical clue is worthpursuing or should be dismissed as a red herring and weighingwhether a proposed test, preventive measure, or treatment entailsa greater risk than the disease itself are essential judgments that askilled clinician must make many times each day. This combinationof medical knowledge, intuition, experience, and judgment definesthe art of medicine , which is as necessary to the practice of medicineas is a sound scientific base._ CLINICAL SKILLSHistory-takingThe written history of an illness should include all the facts of medicalsignificance in the life of the patient. Recent events should begiven the most attention. The patient should, at some early point,have the opportunity to tell his or her own story of the illness withoutfrequent interruption and, when appropriate, receive expressionsof interest, encouragement, and empathy from the physician.Any event related by the patient, however trivial or seeminglyirrelevant, may provide the key to solving the medical problem. Ingeneral, only patients who feel comfortable with the physician willoffer complete information, and thus putting the patient at ease tothe greatest extent possible contributes substantially to obtaining anadequate history.An informative history is more than an orderly listing of symptoms;by listening to patients and noting the way in which theydescribe their symptoms, physicians can gain valuable insight intothe problem. Inflections of voice, facial expression, gestures, andattitude, i.e., body language, may reveal important clues to themeaning of the symptoms to the patient. Because patients vary intheir medical sophistication and ability to recall facts, the reportedmedical history should be corroborated whenever possible. Thesocial history also can provide important insights into the typesof diseases that should be considered. The family history notonly identifies rare Mendelian disorders within a family but oftenreveals risk factors for common disorders, such as coronary heartdisease, hypertension, and asthma. A thorough family history mayrequire input from multiple relatives to ensure completeness andaccuracy, and once recorded, it can be updated readily. The processof history-taking provides an opportunity to observe the patientsbehavior and watch for features to be pursued more thoroughlyduring the physical examination.The very act of eliciting the history provides the physician withan opportunity to establish or enhance the unique bond that formsthe basis for the ideal patient-physician relationship. This processhelps the physician develop an appreciation of the patients perceptionof the illness, the patients expectations of the physician andthe health care system, and the financial and social implications ofthe illness to the patient. Although current health care settings mayimpose time constraints on patient visits, it is important not to rushthe history-taking since this may lead the patient to believe thatwhat he or she is relating is not of importance to the physician and,therefore, may withhold relevant information. The confidentialityof the patient-physician relationship cannot be overemphasized.Physical examinationThe purpose of the physical examination is to identify the physicalsigns of disease. The significance of these objective indications ofdisease is enhanced when they confirm a functional or structuralchange already suggested by the patients history. At times, however,the physical signs may be the only evidence of disease.