An internist evaluates, diagnoses and manages diseases of the heart, lungs, kidneys, blood, lymph nodes, endocrine glands, muscles, bones, joints, intestines and liver. Internists also serve as primary care physicians evaluating common ailments such as rashes, upper respiratory infections, urinary tract infections, back pain, abdominal pain, headaches, depression, anxiety, etc. Usually, an internist is the first doctor you should consult when feeling ill. The reason for this is that often times a problem which may seem to be related to one organ may actually be coming from another. An internist is trained to evaluate for all the possible causes.
For example, chest pain may be from the heart, blood vessels, lungs, intestines or blood disorders. If one concentrates only on one of these organs, a problem in another organ system could be ignored. The vast majority of problems can be diagnosed and managed by an internist. In some cases, an internist will diagnose the condition and refer the patient to a sub-specialist for further management if necessary. Internists also perform routine preventive and annual physical examinations.