Definition

Internal Medicine, nonsurgical medical specialty concerned with diseases of internal organs in adults. Physicians who specialize in the field, known as internists, are skilled in disease prevention and in managing complex disorders of the body. Internists may be either generalists or specialists.

General internists typically act as personal physicians, developing long-term relationships with patients. Internists give patients regular physical examinations, offer preventive care, diagnose and treat most nonsurgical illnesses, and refer serious or unusual cases to an appropriate specialist. If a patient complains of persistent stomach problems, for example, a general internist might refer the patient to a gastroenterologist, an internist who specializes in disorders of the digestive system.

Within the field of internal medicine, nine subspecialties are recognized: cardiology, the treatment of diseases of the heart and blood vessels; endocrinology, the study of glands and other structures that secrete hormones; gastroenterology, the care of conditions of the digestive tract, liver, and pancreas; hematology, the study of blood and blood-forming tissues; infectious disease, the study of severe or unusual infections; nephrology, the diagnosis and treatment of kidney diseases; oncology, the study and treatment of cancerous tumors; pulmonary disease, concerned with disorders of the lungs and other components of the respiratory system; and rheumatology, the treatment of disorders involving joints and other connective tissues. An additional subspecialty gaining prominence is geriatrics, the study of diseases affecting older adults.

The development and widespread use of many technologies have enabled internists to perform procedures that formerly were considered the responsibility of surgeons. For example, a procedure called endoscopy, performed using an illuminated tubular instrument called an endoscope, permits doctors to examine and photograph internal organs and manipulate tools inside the body without invasive surgery. Another tool, a narrow tubular device called a cardiac catheter, permits physicians to inject drugs or fluids directly into the heart.

The origins of internal medicine date back to the late 19th century, when the practices of general medicine and surgery began to split into separate disciplines. Over time, internists became hospital-based generalists who played a role somewhere between those played today by family physicians and surgical specialists. Since the mid-1900s internal medicine in the United States has shifted from a primarily generalist field to a discipline in which roughly 65 percent of all internists are certified as subspecialists.

Those seeking a career in internal medicine must obtain a medical degree and complete a three-year in-hospital internal medicine training program. Internists interested in a subspecialty must spend one or two additional years studying that discipline and must pass a certification test. The specialty board for internal medicine, the American Board of Internal Medicine, was established in 1936.