Internal medicine is a medical specialty in which physicians apply scientific knowledge and clinical expertise to diagnose and treat adults with a very broad range of health concerns and diseases. Physicians who specialize in internal medicine are called internists or general internists.
Internal medicine is the study, diagnosis, and treatment of conditions that affect the internal organs — conditions such as heart disease, hypertension, diabetes, obesity, and lung disease. Internal medicine specialists often care for people with complex, chronic, and multisystem disorders.
Based on their subspecialties, internists may work with doctors in other medical specialties or consult on patients referred by another specialist.
Internal medicine trainees gain experience working in areas that include:
- Endocrinology
- Rheumatology
- Infectious diseases
- Pulmonary diseases
- Cardiovascular diseases
- Critical care medicine
- Hematology
- Oncology
- Gastroenterology
- Nephrology
- Neurology
- Psychiatry
- Dermatology
- Ophthalmology
- Gynecology
- Otorhinolaryngology
- Non-surgical orthopedics
- Palliative medicine
- Sleep medicine
- Geriatrics
- Rehabilitation medicine
Recognized internal medicine subspecialties include:
- Allergy and Immunology (immune system)
- Cardiovascular Disease (heart and vascular system)
- Advanced Heart Failure and Transplant Cardiology
- Interventional Cardiology (heart health)
- Critical Care Medicine (patients with organ system failures)
- Clinical Cardiac Electrophysiology (heart rhythm)
- Endocrinology, Diabetes, and Metabolism (diabetes and other glandular and metabolic disorders)
- Gastroenterology (gastrointestinal system, liver, and gallbladder)
- Transplant Hepatology (liver)
- Hematology (blood)
- Infectious Disease (bacterial, viral, fungal, and parasitic infections)
- Nephrology (kidneys)
- Oncology (cancer)
- Pulmonary Disease (lungs and respiratory system)
- Rheumatology (joints and musculoskeletal system)
Treating a Broad Range of Internal Medicine Conditions
Internal medicine doctors diagnose, manage, and treat a wide range of conditions. These include cancer, infections, and conditions affecting the heart, blood, kidneys, joints, and the digestive, respiratory, and vascular systems. Examples of conditions treated by internists include:
- Abnormal liver biochemical and function tests
- Abnormal uterine bleeding
- Acid peptic disease associated with upper gastrointestinal bleeding
- Acquired thrombotic thrombocytopenic purpura (TTP)
- Acquired von Willebrand syndrome
- Acute aortic dissection
- Acute aortic regurgitation
- Acute bacterial meningitis
- Acute bronchitis
- Acute calculous cholecystitis
- Acute cholangitis
- Acute colonic diverticulitis
- Acute decompensated heart failure
- Acute diverticulitis
- Acute exacerbations of asthma
- Acute ischemic stroke
- Acute liver failure
- Acute lower extremity ischemia
- Acute mesenteric arterial occlusion
- Acute migraine
- Acute myocardial infarction
- Acute pancreatitis
- Acute pericarditis
- Acute pharyngitis
- Acute pulmonary embolism
- Acute respiratory distress syndrome
- Acute sinusitis and rhinosinusitis
- Acute variceal hemorrhage
- Acute viral gastroenteritis
- Adrenal insufficiency
- Airway foreign bodies
- Allergic rhinitis
- Anal fissure
- Angioedema
- Aseptic meningitis
- Aspiration pneumonia
- Atrial fibrillation
- Bacterial brain abscess
- Balanitis and balanoposthitis in children and adolescents
- Bell's palsy
- Bleeding peptic ulcers
- Cancer pain
- Cardiac arrest
- Cardiogenic shock complicating acute myocardial infarction
- Cellulitis and skin abscesses
- Chronic complications and age-related comorbidities in people with hemophilia
- Chronic limb-threatening ischemia
- Clostridial myonecrosis (“gas gangrene”)
- Clostridioides difficile (“C. Diff”) infection (formerly Clostridium difficile)
- Cognitive impairment and dementia
- Colonic ischemia
- Constrictive pericarditis
- Convulsive status epilepticus in adults
- Corneal abrasions and corneal foreign bodies
- Cushing's syndrome
- Diabetic ketoacidosis and hyperosmolar hyperglycemic state in adults
- Disseminated intravascular coagulation
- Dysphagia in adults
- Electrocardiographic abnormalities suggesting myocardial ischemia and infarction
- Emergency contraception
- Epilepsy and electroencephalogram (EEG)
- Esophageal disease
- Exacerbations of chronic obstructive pulmonary disease (COPD)
- Exercise-associated hyponatremia
- External otitis
- Failed fibrinolysis (thrombolysis) or threatened reocclusion in acute ST-elevation myocardial infarction
- Fasting ketosis and alcoholic ketoacidosis
- Gastrointestinal infections
- Giant-cell arteritis
- Gout flares
- HELLP syndrome (hemolysis, elevated liver enzymes, and low platelets)
- Hepatic encephalopathy
- Hereditary thrombotic thrombocytopenic purpura (TTP)
- Hyperkalemia
- Hypotonic hyponatremia
- Infections of cerebrospinal-fluid shunts and other devices
- Ingested foreign bodies and food impactions in adults
- Intestinal ischemia
- Intracranial epidural abscess
- Invasive group A streptococcal infection and toxic shock syndrome
- Lactic acidosis
- Lower gastrointestinal bleeding
- Lyme disease
- Malignancy-related superior vena cava syndrome
- Massive hemoptysis
- Mechanical colorectal obstruction
- Mechanical small-bowel obstruction
- Mesenteric venous thrombosis
- Metabolic acidosis
- Metabolic acidosis in chronic kidney disease
- Metabolic alkalosis
- Mineral and bone metabolism
- Mitral-valve prolapse and flail mitral leaflet
- Moderate to severe hypertensive retinopathy and hypertensive encephalopathy
- Myopericardial disease
- Narrow QRS complex tachycardias
- Necrotizing soft-tissue infections
- Neoplastic epidural spinal-cord compression
- Neuromuscular disease
- Neuropathies
- New-onset atrial fibrillation
- Non-HIV viral infections
- Non-sustained ventricular tachycardia
- Nonocclusive mesenteric ischemia
- Open-angle glaucoma
- Osmotic demyelination syndrome (ODS) and overly rapid correction of hyponatremia
- Osteonecrosis (avascular necrosis of bone)
- Ovarian and fallopian-tube torsion
- Pelvic inflammatory disease
- Perianal and perirectal abscess
- Peripheral nerve and muscle disease
- Pneumothorax
- Pregnancy complications
- Prerenal disease and acute tubular necrosis in acute kidney injury
- Pulmonary infections
- Retinal detachment
- Rhabdomyolysis
- Right-sided native-valve infective endocarditis
- Second- and third-degree atrioventricular blocks
- Secondary spontaneous pneumothorax
- Segmental colitis associated with diverticulosis
- Severe Crohn’s disease
- Severe hypovolemia or hypovolemic shock
- Severe ulcerative colitis
- Sickle cell disease
- Simple and mixed acid-base disorders
- Sinus bradycardia
- Spinal epidural abscess
- Spontaneous bacterial peritonitis
- Staphylococcal toxic shock syndrome
- Stevens-Johnson syndrome and toxic epidermal necrolysis
- Streptococcal pharyngitis
- Subacute kidney injury
- Supraventricular arrhythmias after myocardial infarction
- Suspected acute coronary syndrome (myocardial infarction, unstable angina)
- Suspected nephrolithiasis
- Suspected nonvertebral osteomyelitis
- Sustained monomorphic ventricular tachycardia in patients with structural heart disease
- Symptomatic aortic stenosis
- Syncope
- Thoracic aortic aneurysm
- Thyroid storm
- Transient ischemic attack (TIA)
- Tubo-ovarian abscess
- Tumor lysis syndrome
- Unexplained thrombocytopenia
- Unstable angina and non-ST elevation myocardial infarction
- Upper gastrointestinal bleeding
- Urinary tract obstruction and hydronephrosis
- Ventricular arrhythmias
- Ventricular arrhythmias during acute myocardial infarctio
- Vertigo
- Viral encephalitis
- Wide QRS complex tachycardias
