Trisha Shetty (Editor)

Internal medicine

Updated on
Share on FacebookTweet on TwitterShare on LinkedInShare on Reddit

Internal medicine or general medicine (in Commonwealth nations) is the medical specialty dealing with the prevention, diagnosis, and treatment of adult diseases. Physicians specializing in internal medicine are called internists, or physicians (without a modifier) in Commonwealth nations. Internists are skilled in the management of patients who have undifferentiated or multi-system disease processes. Internists care for hospitalized and ambulatory patients and may play a major role in teaching and research.


Because internal medicine patients are often seriously ill or require complex investigations, internists do much of their work in hospitals. Internists often have subspecialty interests in diseases affecting particular organs or organ systems.

Internal medicine is also a specialty within clinical pharmacy and veterinary medicine.


Historically, some of the oldest traces of internal medicine can be traced from Ancient India and Ancient China. Earliest texts about internal medicine are the Ayurvedic anthologies of Charaka.

Internal medicine physicians have practiced both in clinics and in hospitals, often in the same day. Pressures on time have led to many internal medicine physicians to choose one practice setting, who may choose to practice only in the hospital, as a "hospitalist", or only in an outpatient clinic, as a primary care physician.


The term internal medicine originates from the German term Innere Medizin, popularized in Germany in the late 19th century to describe physicians who combined the science of the laboratory with the care of patients. Many early-20th century American physicians studied medicine in Germany and brought this medical field to the United States. Thus, the name "internal medicine" was adopted in imitation of the existing German term.

Much confusion surrounds the meaning of internal medicine and the role of an "internist." Internists are qualified physicians with postgraduate training in internal medicine and should not be confused with "interns", who are doctors in their first year of residency training (officially the term intern is no longer in use). Although internists may act as primary care physicians, they are not "family physicians," "family practitioners," or "general practitioners," whose training is not solely concentrated on adults and may include surgery, obstetrics, and pediatrics. The American College of Physicians defines internists as "physicians who specialize in the prevention, detection and treatment of illnesses in adults".

Education and training of internists

The training and career pathways for internists vary considerably across the world.

Many programs require previous undergraduate education prior to medical school admission. This "pre-medical" education is typically four or five years in length. Graduate medical education programs vary in length by country. Medical education programs are tertiary-level courses, undertaken at a medical school attached to a university. In the United States, medical school consists of four years. Hence, gaining a basic medical education may typically take eight years, depending on jurisdiction and university.

Following completion of entry-level training, newly graduated medical practitioners are often required to undertake a period of supervised practice before the licensure, or registration, is granted, typically one or two years. This period may be referred to as "internship", "conditional registration", or "foundation programme". Then, doctors may finally follow specialty training in internal medicine if they wish, typically being selected to training programs through competition. In North America, this period of postgraduate training is referred to as residency training, followed by an optional fellowship if the internist decides to train in a subspecialty. In Commonwealth countries, during that training period in internal medicine, trainees are often called senior house officers, and advance to registrar grade when they undergo a compulsory subspecialty training whilst commonly continuing service provision in the main speciality. In the United States, residency training for internal medicine lasts three years.

Certification of specialists

In the United States, three organizations are responsible for certification of trained internists (i.e., doctors who have completed an accredited residency training program) in terms of their knowledge, skills, and attitudes that are essential for excellent patient care: the American Board of Internal Medicine, the American Osteopathic Board of Internal Medicine and the Board of Certification in Internal Medicine.

United States

In the United States, two organizations are responsible for certification of subspecialists within the field: the American Board of Internal Medicine and the American Osteopathic Board of Internal Medicine. Physicians (not only internists) that successfully pass board exams get "board certified" status, and, as of 2011, earn on average an 88.8% higher salary in the USA.

American Board of Internal Medicine

The following are the subspecialties recognized by the American Board of Internal Medicine.

  • Adolescent medicine
  • Allergy, Asthma and Immunology, concerned with the diagnosis, treatment and management of allergies, asthma and disorders of the immunology system.
  • Cardiology, dealing with disorders of the heart and blood vessels*
  • Clinical cardiac electrophysiology
  • Critical care medicine
  • Endocrinology, dealing with disorders of the endocrine system and its specific secretions called hormones
  • Gastroenterology, concerned with the field of digestive diseases
  • Geriatric medicine
  • Hematology, concerned with blood, the blood-forming organs and its disorders.
  • Hospital medicine
  • Infectious disease, concerned with disease caused by a biological agent such as by a virus, bacterium or parasite
  • Interventional cardiology
  • Medical oncology, dealing with the chemotherapeutic (chemical) treatment of cancer
  • Nephrology, dealing with the study of the function and diseases of the kidney
  • Pulmonology, dealing with diseases of the lungs and the respiratory tract
  • Rheumatology, devoted to the diagnosis and therapy of rheumatic diseases.
  • Sleep medicine
  • Sports medicine
  • Transplant hepatology
  • American College of Osteopathic Internists

    The American College of Osteopathic Internists recognizes the following subspecialties:

  • Allergy/Immunology
  • Cardiology
  • Critical care medicine
  • Endocrinology
  • Gastroenterology
  • Geriatric medicine
  • Hematology/Oncology
  • Infectious diseases
  • Nuclear medicine
  • Nephrology
  • Pulmonology
  • Rheumatology
  • United Kingdom

    In the United Kingdom, the three medical Royal Colleges (the Royal College of Physicians of London, the Royal College of Physicians of Edinburgh and the Royal College of Physicians and Surgeons of Glasgow) are responsible for setting curricula and training programmes through the Joint Royal Colleges Postgraduate Training Board (JRCPTB), although the process is monitored and accredited by the General Medical Council (which also maintains the specialist register).

    Doctors who have completed medical school spend two years in foundation training completing a basic postgraduate curriculum. After two years of Core Medical Training (CT1/CT2) and attaining the Membership of the Royal College of Physicians, physicians commit to one of the medical specialties:

  • Acute medicine (with possible accreditations in stroke medicine or pre-hospital emergency medicine)
  • Allergy
  • Audiovestibular medicine
  • Cardiology (with possible accreditation in stroke medicine)
  • Clinical genetics
  • Clinical neurophysiology
  • Clinical pharmacology and therapeutics (with possible accreditation in stroke medicine)
  • Dermatology
  • Endocrinology and diabetes mellitus
  • Gastroenterology (with possible accreditation in hepatology)
  • General (internal) medicine (with possible accreditation in metabolic medicine or stroke medicine)
  • Genito-urinary medicine
  • Geriatric medicine (with possible accreditation in stroke medicine)
  • Haematology
  • Immunology
  • Infectious diseases
  • Medical oncology (clinical or radiation oncology falls under the Royal College of Radiologists, although entry is through CMT and MRCP is required)
  • Medical ophthalmology
  • Neurology (with possible accreditation in stroke medicine)
  • Nuclear medicine
  • Paediatric cardiology (the only pediatric subspecialty not under the Royal College of Paediatrics and Child Health)
  • Palliative medicine
  • Pharmaceutical medicine
  • Rehabilitation medicine (with possible accreditation in stroke medicine)
  • Renal medicine
  • Respiratory medicine
  • Rheumatology
  • Sport and exercise medicine
  • Tropical medicine
  • Many training programmes provide dual accreditation with general (internal) medicine and are involved in the general care to hospitalised patients. These are acute medicine, cardiology, clinical pharmacology and therapeutics, endocrinology and diabetes mellitus, gastroenterology, infectious diseases, renal medicine, respiratory medicine and often, rheumatology. The role of general medicine, after a period of decline, was reemphasised by the Royal College of Physicians of London report from the Future Hospital Commission (2013).

    Medical diagnosis and treatment

    Medicine is mainly focused on the art of diagnosis and treatment with medication, but many subspecialties administer procedural treatment:

  • Cardiology: angioplasty, cardioversion, cardiac ablation, intra-aortic balloon pump
  • Critical care medicine: mechanical ventilation
  • Gastroenterology: endoscopy and ERCP
  • Nephrology: dialysis
  • Pulmonology: Bronchoscopy
  • References

    Internal medicine Wikipedia