Medical and Scientific

See medication, and pharmacology for the substances or medicines that are used to treat patients. This article is about the field of medical practice and healthcare.

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Medicine is a branch of health science concerned with maintaining human health and restoring it by treating disease and injury; it is both an area of knowledge, a science of body systems and diseases and their treatment, and the applied practice of that knowledge.

The practice of medical care is shared between the medical profession—physicians or doctors—and other groups of professionals, such as nurses or pharmacists (sometimes called allied health professions). Historically, only members of the medical profession proper have been considered to actually practice medicine in the strictest sense, in contrast to the allied fields of health care professionals. Clinicians can be physicians, nurses, or physician assistants -- those who provide health care or otherwise tend to their patients. The medical profession is the social and occupational structure of the group of people formally trained and authorized to apply medical knowledge. Many countries and legal jurisdictions have legal limitations on who may practice medicine or the allied medical fields.

Medicine is typically seen as composed of various specialized sub-branches, such as pediatrics, gynecology, neurology, dealing with particular body systems, diseases, or areas of health.

Systems of medical and healthcare practices have existed among human societies since at least the dawn of recorded history. These systems have developed in various ways in different cultures and regions. Medicine as understood in the modern period has historically been considered to be the mainstream tradition which developed in the Western world since the early modern age. Many other traditions of medicine and healthcare are still widely practiced throughout the world, most of which are still considered to be separate and distinct from Western medicine, also called biomedicine or the Hippocratic tradition. The most highly developed systems of medicine outside the Western system are the Ayurvedic tradition of India and traditional Chinese medicine. Various non-mainstream traditions of health care have also developed in the Western world distinct from mainstream medicine. The various other systems practiced among various cultures are sometimes practiced alongside or in cooperation with Western medicine, while sometimes being seen as competing traditions.

Medicine is also often used amongst medical professionals as shorthand for Internal Medicine.

Veterinary medicine is the practice of health care specialized for other animal species.

History of medicine

Main article: History of medicine

Medicine as it is practiced now is rooted in various traditions, but developed mainly in the late 18th and early 19th century in Germany (Rudolf Virchow) and France (Jean-Martin Charcot, Claude Bernard and others). The new, "scientific" medicine replaced earlier Western traditions of medicine, mostly based on the "four humours" and other pre-modern theories. The focal points of development of clinical medicine shifted to the United Kingdom and the USA by the early 1900s (Sir William Osler, Harvey Cushing).

Evidence-based medicine is the recent movement to link the practice and the science of medicine more closely through the use of the scientific method and modern information science.

Genomics and knowledge of human genetics is already having a large influence on medicine, as the causative genes of most monogenic genetic disorders have now identified, and the development of techniques in molecular biology and genetics are influencing medical practice and decision-making.

Practice of medicine

The practice of medicine combines both science and art. Science and technology are the evidence base for many clinical problems for the general population at large. The art of medicine is the application of this medical knowledge in combination with intuition and clinical judgment to determine the proper diagnoses and treatment plan for this unique patient and to treat the patient accordingly.

Central to medicine is the patient-doctor relationship established when a person with a health concern or problem seeks the help of a physician (i.e. the medical encounter). Other health professionals similarly establish a relationship with a patient and may perform interventions from their perspective, e.g. nurses, radiographers and therapists.

As part of the medical encounter, the doctor needs to:

• develop a relationship with the patient
• gather data (medical history and physical examination combined with laboratory or imaging studies)
• analyze and synthesize that data (assessment and/or differential diagnosis), and then
• develop a treatment plan (further testing, therapy, watchful observation, referral and follow-up)
• treat the patient accordingly
• assess the progress of treatment and alter the plan as necessary.

The medical encounter is documented in a medical record, which is a legal document in many jurisdictions. One method that is used is called the problem-oriented medical record (POMR), which includes a problem list of diagnoses and a "SOAP" method of documentation for each visit:

• S - Subjective, the medical history of the problem from the point-of-view of the patient.
• O - Objective, the physical examination and any laboratory or imaging studies.
• A - Assessment, is the medical decision-making process including the differential diagnoses and most probable diagnoses.
• P - Plan, the way resolve the problem and monitor progress

Healthcare delivery systems

Medicine is practiced within the medical system, which is a legal, credentialing and financing framework, established by a particular culture or government. The characteristics of a healthcare system have significant effect on the nature and format of how medical care is delivered.

Financing framework has the greatest influence, as it defines who pays the cost and how medical practitioners are compensated. Aside from tribal cultures, the most significant divide in developed countries is that between universal health care and the market based health care (such as practiced in the U.S.). Universal healthcare might allow or ban a parallel private market. The latter case is described as single-payor system.

Patient-doctor relationship

The doctor-patient relationship and interaction is a central process in the practice of medicine. There are many perspectives from which to understand and describe it.

An idealized physician's perspective, such as is taught in medical school, sees the core aspects of the process as the physician learning from the patient his symptoms, concerns and values; in response the physician examines the patient, interprets the symptoms, and formulates a diagnosis to explain the symptoms and their cause to the patient and to propose a treatment. In more detail, the patient presents a set of complaints or concerns about his health to the doctor, who then obtains further information about the patient's symptoms, previous state of health, living conditions, and so forth, and then formulates a diagnosis and enlists the patient's agreement to a treatment plan. Importantly, during this process the doctor educates the patient about the causes, progression, outcomes, and possible treatments of his ailments, as well as often providing advice for maintaining health. This teaching relationship is the basis of calling the physician doctor, which originally meant "teacher" in Latin. The patient-doctor relationship is additionally complicated by the patient's suffering (patient derives from the Latin patiens, "suffering") and limited ability to relieve it on his own. The doctor's expertise comes from his knowledge about, or experience with, other people who have suffered similar symptoms, and his presumed ability to relieve it with medicines or other therapies about which the patient may initially have little knowledge.

The doctor-patient relationship can be analyzed from the perspective of ethical concerns, in terms of how well the goals of non-maleficence, beneficence, autonomy, and justice are achieved. Many other values and ethical issues can be added to these. In different societies, periods, and cultures, different values may be assigned different priorities. For example, in the last 30 years medical care in the Western World has increasingly emphasized patient autonomy in decision making.

The relationship and process can also be analyzed in terms of social power relationships (e.g., by Michel Foucault), or economic transactions. Physicians have been accorded gradually higher status and respect over the last century, and they have been entrusted with control of access to prescription medicines as a public health measure. This represents a concentration of power and carries both advantages and disadvantages to particular kinds of patients with particular kinds of conditions. A further twist has occurred in the last 25 years as costs of medical care have risen, and a third party (an insurance company or government agency) now often insists upon a share of decision-making power for a variety of reasons, reducing freedom of choice of both doctors and patients in many ways.

The quality of the patient-doctor relationship is important to both parties. The better the relationship in terms of mutual respect, knowledge, trust, shared values and perspectives about disease and life, and time available, the better will be the amount and quality of information about the patient's disease transferred in both directions, enhancing accuracy of diagnosis and increasing the patient's knowledge about the disease.

In some settings, e.g. the hospital ward, the patient-doctor relationship is much more complex, and many other people are involved when somebody is ill: relatives, neighbors, rescue specialists, nurses, technical personnel, social workers and others.

Clinical skills

Main articles: Medical history, Physical examination.

A complete medical evaluation includes a medical history, a physical examination, appropriate laboratory or imaging studies, analysis of data and medical decision making to obtain diagnoses, and treatment plan.

The components of the medical history are:

• Chief complaint (CC) - the reason for the current medical visit.
• History of present illness (HPI) - the chronological order of events of symptoms. A mnemonic PQRST is sometimes helpful in obtaining the history:
  • Provocative-palliative factors - what makes a symptom worse or better.
  • Quality - description of the symptom
  • Region - which part of the body is affected
  • Severity - what is the intensity of the symptom; using a scale of 0-10 (10 worst)
  • Timing - what is the course of the symptom
• Current activity - occupation, hobbies, what the patient actually does.
• Medications - what drugs including OTCs, and home remedies, as well as herbal remedies such as St. John's Wort. Allergies are recorded.
• Past medical history (PMH/PMHx) - other medical diagnoses, past hospitalizations and operations, injuries, past infectious diseases and/or vaccinations, history of known allergies.
• Review of systems (ROS) - an outline of additional symptoms to ask which may be missed on HPI, generally following the body's main organ systems (heart, lungs, digestive tract, urinary tract, etc).
• Social history (SH) - birthplace, residences, marital history, social and economic status, habits (including diet, medications, tobacco, alcohol).
• Family history (FH) - listing of diseases in the family that may impact the patient. A family tree is sometimes used.

The physical examination is the examination of the patient looking for signs of disease. The doctor uses his senses of sight, hearing, touch, and sometimes smell (taste has been made redundant by the availability of modern lab tests). Four chief methods are used: inspection, palpation, percussion, and auscultation; smelling may be useful (e.g. infection, uremia, diabetic ketoacidosis). The clinical examination involves study of:

• Vital signs include height, weight, body temperature, blood pressure, pulse, respiration rate, hemoglobin oxygen saturation
• General appearance of the patient
• Skin
• Head, eye, ear, nose, and throat (HEENT)
• Cardiovascular - heart and blood vessels
• Respiratory - lungs
• Abdomen and rectosigmoid
• Genitalia
• Spine and extremities - musculoskeletal
• Neurological and psychiatric

Laboratory and imaging studies results may be obtained, if ncessary.

The medical decision-making (MDM) process involves analysis and synthesis of all the above data to come up with a list of possible diagnoses (the differential diagnoses), along with an idea of what needs to be done to obtain a definitive diagnosis that would explain the patient's problem.

The treatment plan may include ordering additional laboratory tests and studies, starting therapy, referral to a specialist, or watchful observation. Follow-up may be advised.

This process is used by primary care providers as well as specialists. It may take only a few minutes if the problem is simple and straightforward. On the other hand, it may take weeks in a patient who has been hospitalized with multi-system problems, with involvement by several specialists.

On subsequent visits, the process may be repeated in an abbreviated manner to obtain any new history, symptoms, physical findings, and lab or imaging results or specialist consultations.

Settings where medical care is delivered

See also clinic, hospital, and hospice

Medicine is a diverse field and the provision of medical care is therefore provided in a variety of locations.

Primary care medical services are provided by physicians or other health professionals who has first contact with a patient seeking medical treatment or care. These occur in physician's office, clinics, nursing homes, schools, home visits and other places close to patients. About 90% of medical visits can be treated by the primary care provider. These include treatment of acute and chronic illnesses, preventive care and health education for all ages and both sex.

Secondary care medical services are provided by medical specialists in their offices or clinics or at local community hospitals for a patient referred by a primary care provider who first diagnosed or treated the patient. Referrals are made for those patients who required the expertise or procedures performed by specialists. These include both ambulatory care and inpatient services, emergency rooms, intensive care medicine, surgery services, physical therapy, labor and delivery, endoscopy units, diagnostic laboratory and medical imaging services, hospice centers, etc. Some primary care providers may also take care of hospitalized patients and deliver babies in a secondary care setting.

Tertiary care medical services are provided by specialist hospitals or regional centers equipped with diagnostic and treatment facilities not generally available at local hospitals. These include trauma centers, burn treatment centers, advanced neonatology unit services, organ transplants, high-risk pregnancy, radiation oncology, etc.

Modern medical care also depends on information - still delivered in many health care settings on paper records, but increasingly nowadays by electronic means.

Branches of medicine

Working together as an interdisciplinary team, many highly trained health professionals besides medical practitioners are involved in the delivery of modern health care. Some examples include: nurses, laboratory scientists, pharmacists, physiotherapists, speech therapists, occupational therapists, dietitians and bioengineers.

The scope and sciences underpinning human medicine overlap many other fields. Dentistry and psychology, while separate disciplines from medicine, are sometimes also considered medical fields. Physician assistants, nurse practitioners and midwives treat patients and prescribe medication in many legal jurisdictions. Veterinary medicine applies similar techniques to the care of animals.

Medical doctors have many specializations and subspecializations which are listed below.

Basic sciences

• Anatomy is the study of the physical structure of organisms. In contrast to macroscopic or gross anatomy, cytology and histology are concerned with microscopic structures.
• Biochemistry is the study of the chemistry taking place in living organisms, especially the structure and function of their chemical components.
• Biostatistics is the application of statistics to biological fields in the broadest sense. A knowledge of biostatistics is essential in the planning, evaluation, and interpretation of medical research. It is also fundamental to epidemiology and evidence-based medicine.
• Cytology is the microscopic study of individual cells.
• Embryology is the study of the early development of organisms.
• Epidemiology is the study of the demographics of disease processes, and includes, but is not limited to, the study of epidemics.
• Genetics is the study of genes, and their role in biological inheritance.
• Histology is the study of the structures of biological tissues by light microscopy, electron microscopy and immunohistochemistry.
• Immunology is the study of the immune system, which includes the innate and adaptive immune system in human, for example.
• Microbiology is the study of microorganisms, including protozoa, bacteria, fungi, and viruses.
• Neuroscience is a comprehensive term for those disciplines of science that are related to the study of the nervous system. A main focus of neuroscience is the biology and physiology of the human brain.
• Nutrition is the study of the relationship of food and drink to health and disease, especially in determining an optimal diet. Medical nutrition therapy is done by dietitians and is prescribed for diabetes, cardiovascular diseases, weight and eating disorders, allergies, malnutrition and neoplastic diseases.
• Pathology is the study of disease - the causes, course, progression and resolution thereof.
• Pharmacology is the study of drugs and their actions.
• Physiology is the study of the normal functioning of the body and the underlying regulatory mechanisms.
• Toxicology is the study of hazardous effects of drugs and poisons.

Diagnostic specialties

• Clinical laboratory sciences are the clinical diagnostic services which apply laboratory techniques to diagnosis and management of patients. In the United States these services are supervised by a Pathologist. The personnel that work in these medical laboratory departments are technically trained staff, each of whom usually hold a medical technology degree, who actually perform the tests, assays, and procedures needed for providing the specific services.
  • Transfusion medicine is concerned with the transfusion of blood and blood component, including the maintenance of a "blood bank".
  • Cellular pathology is concerned with diagnosis using samples from patients taken as tissues and cells using histology and cytology.
  • Clinical chemistry is concerned with diagnosis by making biochemical analysis of blood, body fluids and tissues.
  • Hematology is concerned with diagnosis by looking at changes in the cellular composition of the blood and bone marrow as well as the coagulation system in the blood.
  • Clinical microbiology is concerned with the in vitro diagnosis of diseases caused by bacteria, viruses, fungi, and parasites.
  • Clinical immunology is concerned with disorders of the immune system and related body defenses. It also deals with diagnosis of allergy.
• Radiology is concerned with imaging of the human body, e.g. by x-rays, x-ray computed tomography, ultrasonography, and nuclear magnetic resonance tomography.
  • Interventional radiology is concerned with using imaging of the human body, usually from CT, ultrasound, or fluoroscopy, to do biopsies, place certain tubes, and perform intravascular procedures.
  • Nuclear Medicine uses radioactive substances for in vivo and in vitro diagnosis using either imaging of the location of radioactive substances placed into a patient, or using in vitro diagnostic tests utilizing radioactive substances.

Clinical disciplines

• Anesthesiology (AE), Anaesthesia (BE), is the clinical discipline concerned with providing anesthesia. Pain medicine is often practiced by specialised anesthesiologists.
• Dermatology is concerned with the skin and its diseases.
• Emergency medicine is concerned with the diagnosis and treatment of acute or life-threatening conditions, including trauma, surgical, medical, pediatric, and psychiatric emergencies.
• General practice, Family practice, family medicine or primary care is, in many countries, the first port-of-call for patients with non-emergency medical problems. Family doctors are usually able to treat over 90% of all complaints without referring to specialists.
• Hospital medicine is the general medical care of hospitalized patients. Doctors whose primary professional focus is hospital medicine are called hospitalists.
• Internal medicine is concerned with systemic diseases of adults, i.e. those diseases that affect the body as a whole , (restrictive ,current meaning) or with all adult non-operative somatic medicine (traditional , inclusive meaning) , thus excluding pediatrics , surgery , gynaecology & obstetrics and psychiatry. There are several subdisciplines of internal medicine:
  • Cardiology is concerned with the heart and cardiovascular system and their diseases.
  • Critical care medicine is concerned with the therapy of patients with serious and life-threatening disease or injury. Intensive care medicine employs invasive diagnostic techniques and (temporary) replacement of organ functions by technical means. Also known as Intensive care medicine. This field is often associated with Pulmonology.
  • Endocrinology is concerned with the endocrine system, i.e. endocrine glands and hormones, usually Diabetes or Thyroid diseases.
  • Gastroenterology is concerned with the alimentary tract.
  • Geriatrics is concerned with medical care of the elderly.
  • Hematology (or haematology) is concerned with the blood and its diseases.
  • Hepatology is concerned with the liver and biliary tract, and is usually a part of Gastroenterology
  • Infectious diseases is concerned with the study, diagnosis and treatment of diseases caused by biological agents.
  • Nephrology is concerned with diseases of the kidneys.
  • Oncology is devoted to the study, diagnosis and treatment of cancer and other malignant diseases, and is often grouped with Hematology.
  • Pulmonology (or chest medicine, respiratory medicine or lung medicine) is concerned with diseases of the lungs and the respiratory system.
  • Rheumatology is devoted to the diagnosis and treatment of inflammatory diseases of the joints and other organ systems, such as arthritis.
• Neurology is concerned with the diagnosis and treatment of nervous system diseases.
• Obstetrics and Gynecology (often abbreviated as Ob/Gyn) are concerned respectively with childbirth and the female reproductive and associated organs. Reproductive medicine and fertility medicine are generally practiced by gynecological specialists.
• Palliative care is a relatively modern branch of clinical medicine that deals with pain and symptom relief and emotional support in patients with terminal diseases (cancer, heart failure).
• Pediatrics (or paediatrics) is devoted to the care of infants, children, and adolescents. Like internal medicine, there are many pediatric subspecialities for specific age ranges, organ systems, disease classes and sites of care delivery. Most subspecialities of adult medicine have a pediatric equivalent such as pediatric cardiology, pediatric endocrinology, pediatric gastroenterology, pediatric hematology, and pediatric oncology, pediatric ophthalmology, and neonatology.
• Physical medicine and rehabilitation (or physiatry) is concerned with functional improvement after injury, illness, or congenital abnormality.
• Preventive medicine is the branch of medicine concerned with preventing disease.
  • Community health care or public health is an aspect of health services concerned with threats to the overall health of a community based on population health analysis.
  • Occupational medicine's principal role is the provision of health advice to organisations and individuals to ensure that the highest standards of health and safety at work can be achieved and maintained.
• Psychiatry is a branch of medicine that studies and treats mental disorders. Related non-medical fields are psychotherapy and clinical psychology. There are several subdisciplines of Psychiatry:
  • Child & adolescent psychiatry focuses on the care of children and adolescents with mental/emotional/learning problems (i.e., ADHD, Autism, family conflicts).
  • Geriatric psychiatry focuses on the care of elderly people with mental illnesses (i.e., dementias, post stroke cognitive changes, depression).
  • Addiction psychiatry focuses on substance abuse and its treatment.
  • Forensic psychiatry focuses on the interface of psychiatry and the Law.
• Radiation therapy is concerned with the therapeutic use of ionizing radiation and high energy elementary particle beams in patient treatment.
• Surgical specialties - there are many medical disciplines that employ operative treatment. Some of these are highly specialized and are often not considered subdisciplines of surgery, although their naming might suggest so.
  • General surgery is traditionally defined as the specialty of surgery of the skin, endocrine glands, and abdomen (and, sometimes, the mammary glands). In some countries, it is still deemed a pre-requisite training prior to progression to training in certain sub-specialties, but lately has evolved into its own sub-specialty.
  • Cardiovascular surgery is the surgical specialty that is concerned with the heart and major blood vessels of the chest.
  • Neurosurgery is concerned with the operative treatment of diseases of the nervous system.
  • Maxillofacial surgery is concerned with the operative treatment of deseases, deformities and other conditions of lower and middle one-third of face, including oral cavity and teeth (technically a subspeciality of dentistry)
  • Ophthalmology deals with the diseases of the eyes and their treatment.
  • Orthopedic surgery consists on surgery of the locomotor system.
  • Otolaryngology (or otorhinolaryngology or ENT/ear-nose-throat) is concerned with treatment of ear, nose and throat disorders. The term head and neck surgery defines a closely related specialty which is concerned mainly with the surgical management of cancer of the same anatomical structures.
  • Pediatric surgery treats a wide variety of thoracic and abdominal (and sometimes urologic) diseases of childhood.
  • Plastic surgery includes aesthetic surgery (operations that are done for other than medical purposes) as well as reconstructive surgery (operations to restore function and/or appearance after traumatic or operative mutilation).
  • Surgical oncology is concerned with curative and palliative surgical approaches to cancer treatment.
  • Urology focuses on the urinary tracts of males and females, and on the male reproductive system. It is often practiced together with andrology ("men's health").
  • Vascular surgery is surgery of "peripheral" blood vessels, i.e. those outside of the chest (usually operated on by cardiovascular surgeons) and of the central nervous system (treated by neurosurgery).
• Urgent Care focuses on delivery of unscheduled, walk-in care outside of the hospital emergency department for injuries and illnesses that are not severe enough to require care in an emergency department.

Interdisciplinary fields

Interdisciplinary sub-specialties of medicine are:

• Aerospace medicine deals with medical problems related to flying and space travel.
• Bioethics is a field of study which concerns the relationship between biology, science, medicine and ethics, philosophy and theology.
• Clinical pharmacology is concerned with how systems of therapeutics interact with patients.
• Conservation medicine studies the relationship between human and animal health, and environmental conditions. Also known as ecological medicine, environmental medicine, or medical geology.
• Diving medicine (or hyperbaric medicine) is the prevention and treatment of diving-related problems.
• Evolutionary medicine is a perspective on medicine derived through applying evolutionary theory.
• Forensic medicine deals with medical questions in legal context, such as determination of the time and cause of death.
• Medical humanities includes the humanities (literature, philosophy, ethics, history and religion), social science (anthropology, cultural studies, psychology, sociology), and the arts (literature, theater, film, and visual arts) and their application to medical education and practice.
• Medical informatics and medical computer science are relatively recent fields that deal with the application of computers and information technology to medicine.
• Nosology is the classification of diseases for various purposes.
• Sports medicine deals with the treatment and preventive care of athletics, amateur and professional. The team includes specialty physicians and surgeons, athletic trainers, physical therapists, coaches, other personnel, and, of course, the athlete.
• Therapeutics is the field, more commonly referenced in earlier periods of history, of the various remedies that can be used to treat disease and promote health [1] [2].
• Travel medicine or emporiatrics deals with health problems of international travelers or travelers across highly different evironments.

Medical education

See also Medical doctor (BE), Physician (AE), and Medical school.

Medical training involves several years of university study followed by several more years of residential practice at a hospital. Entry to a medical degree in some countries (such as the United States) requires the compl