Internal medicine is the branch of medicine that deals with treating the whole patient. An internal medicine physician, also called an internist, can treat many illnesses and conditions, and is skilled in treating a patient who has several illnesses or disorders at the same time. This internist, who can be a primary care physician, emphasizes disease prevention and wellness, but can treat problems of the eyes, ears, skin, nervous system and reproductive organs, along with mental health or substance abuse issues.

The internal medicine physician can also treat cancer or diseases of the heart, blood, kidneys, joints, and digestive, respiratory and vascular systems, while concentrating on the wellness of the patient as a whole.

Physicians in this specialty treat patients suffering from numerous diseases and illnesses, but some of the most common are Emphysema, Broncho-Esophagology, Bronchitis, Pneumonia, Osteoarthritis , Hyper / Hypoglycemia, cystic fibrosis, Diabetes, Asthma, pectus excavatum, osteoporosis, Macular Degeneration, cancer, infection, Autism, Congestive heart failure, Herpes, Hypertension, Heart Attack, and Anemia.

Once properly diagnosed, practitioners can perform numerous procedures on patients including Lithotripsy, Endoscopic retrograde cholangiopancreatography (ERCP, dialysis, angioplasty, mechanical ventilation, endoscopy, cardioversion, Endoscopic retrograde cholangiopancreatography (ERCP), cardiac ablation, and intra-aortic balloon pump.

To diagnose patients with possible illnesses and diseases, specialists will often perform one of many tests including FAA-Flight Physicial, physicial / check up, Bone density test, dialysis, physicial examination, Computed Axial Tomography (CT or CAT Scan), Magnetic Resonance Imaging (MRI), ultrasound, x-ray, biopsy, Blood Test, Electrocardiogram (ECG or EKG), Upper GI (Barium Swallow), electrolyte test, Lower GI (Barium Enema), stool test, pH probe test, and microbiological culture.

Doctor density varies by specialty and location. Illinois has 5,588 practicing internal medicine doctors. Broken out by city, internal medicine doctor density in Alton is 56, in Aurora is 69, in Batavia is 9, in Belleville is 34, in Berwyn is 45, in Bloomington is 64, in Blue Island is 20, in Braidwood is 2, in Burbank is 24, in Calumet City is 19, in Canton is 6, in Carbondale is 12, in Carlyle is 3, in Carmi is 3, in Centralia is 8, in Champaign is 43, in Chicago is 2,209, in Chicago Heights is 32, in Christopher is 3, in Cicero is 13, in Collinsville is 5, in Crystal Lake is 40, in Danville is 36, in Darien is 13, in Decatur is 36, in Dekalb is 12, in Des Plaines is 77, in Dixon is 7, in Edwardsville is 11, in Effingham is 16, in Elgin is 55, in Elmhurst is 64, in Eureka is 2, in Evanston is 242, in Fairview Heights is 5, in Freeport is 21, in Galesburg is 7, in Geneva is 7, in Granite City is 12, in Harvard is 3, in Harvey is 16, in Herrin is 5, in Hickory Hills is 3, in Highland is 6, in Highland Park is 43, in Jerseyville is 9, in Joliet is 78, in Kankakee is 26, in Kewanee is 6, in Lake Forest is 37, in Lincoln is 4, in Lockport is 3, in Loves Park is 7, in Marion is 28, in Mattoon is 19, in Mchenry is 23, in Moline is 39, in Momence is 3, in Morris is 11, in Mount Vernon is 18, in Murphysboro is 3, in Naperville is 86, in Normal is 33, in North Chicago is 44, in Oak Forest is 33, in Oakbrook Terrace is 10, in Olney is 3, in Ottawa is 7, in Palos Heights is 30, in Palos Hills is 13, in Paris is 3, in Park Ridge is 73, in Pekin is 10, in Peoria is 170, in Peru is 4, in Pinckneyville is 1, in Princeton is 3, in Quincy is 20, in Red Bud is 2, in Rochelle is 2, in Rock Island is 15, in Rockford is 90, in Rolling Meadows is 10, in Sandwich is 4, in Silvis is 14, in Springfield is 173, in Sterling is 9, in Sycamore is 8, in Taylorville is 3, in Urbana is 114, in Vandalia is 3, in Washington is 5, in Watseka is 4, in Waukegan is 28, in Wheaton is 27, in Wilmington is 6, in Wood Dale is 2, in Woodstock is 23, in Yorkville is 8, and in Zion is 9.

Most people think that Chicago, because of its size and popularity, is Illinois’ capital city, but that distinction belongs to Springfield, home of the Abraham Lincoln Museum. Illinois has hundreds of museums, numerous yearly art and ethnic festivals, a lakeshore bordering Lake Michigan, and the many national forests and parks that offers visitors camping, horseback riding, biking, kayaking, and fishing. Chicago is home to the Sears Tower, the Shedd Aquarium, the Art Institute of Chicago, the Adler Planetarium, the Museum of Science and Industry, and other cultural opportunities and restaurants in the Navy Pier area.

According to 2005 Census estimates, Illinois has a population of 12,763,371. Of this population, 3,172,677 are under the age of 18 and 1,523,937 are at or above the age of 65.