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Do you know the 11 sub-specialties of internal medicine?


One of the first places people go to find a specialist is to their insurance company website. Yet, the may not understand the different specialties and refer themselves to the wrong specialist.  This could result in a delayed diagnosis, the wrong diagnosis, the wrong treatment plan or simply wasting your time and money.

To get started in the right direction, you need to be able to find the type of doctor that corresponds to your particular symptom or condition.  There are several types of doctor specialties, however this article will address the sub-specialties of Internal Medicine. 

An Internal Medicine physician is a ‘general doctor for adults.’  Internal Medicine doctors may also be referred to as ‘General Internist,’ ‘Generalist,’ ‘Internist’ or ‘Primary Care Physician’ (PCP).  They are not surgeons.  They do not perform operations.  They listen to patient histories, perform physical exams, make a diagnosis and often prescribe medications to treat a condition or disease.  They often treat aches and pains, sore throats, colds and allergies, high blood pressure, diabetes, indigestion, perform annual physical exams and coordinate some preventive screenings.

Internal Medicine Training

The physician’s training determines the specialty.   After medical school, doctors must complete a residency.  That residency can last anywhere from three to nine years and can be in various areas of medicine—for example, Pediatrics, Ob/GYN and Internal Medicine—are three different types of residencies a doctor can perform.  Often after residency, the doctor wants to further sub-specialize—that is, focus even more on one particular area.  To sub-specialize, the doctor must then complete what is called a fellowship.  That fellowship is an additional two to four years of training.

The sub-specialties of Internal Medicine 

  1. Pulmonology—Pulmonologists are lung doctors that focus on conditions like asthma and emphysema/chronic bronchitis (also called COPD).  Interestingly, they are also experts in sleeping problems (often sleeping problems are related to breathing) with one of their significant focuses being a condition called sleep apnea.
  2. Endocrinology—Endocrinologists are hormone and gland doctors.  These doctors focus on diseases of the thyroid gland (either over or under-active thyroid), diabetes and other hormone conditions.  Diabetes can be confusing because most people with diabetes see their PCP, but there are instances where it may be preferable to see an endocrinologist for diabetes.
  3. Cardiology—Cardiologists are heart and blood vessel doctors.  These doctors focus on preventing heart attacks and treating patients who have had heart attacks.  They also see patients that have a condition called Congestive Heart Failure (or CHF), where the heart does not pump as strong as it should and as a result, patients with CHF tend to retain fluid in their legs and lungs.
  4. Gastroenterology—Gastroenterologists are doctors of the digestive system (esophagus, stomach, small intestine, large intestine, pancreas, and liver).  Gastroenterologist is a rather long word, so it is often just abbreviated as GI doctor (for ‘Gastro-Intestinal’ doctor).  They see patients who have problems with severe or chronic heartburn, indigestion, stomach pain, chronic diarrhea or constipation and a condition called irritable bowel syndrome.
  5. Hepatology—Hepatologists exclusively focus on the liver.  While GI doctors can also see patients with liver problems, Hepatologists typically see patients that have chronic or severe liver conditions. These conditions include Hepatitis A, B or C or people who have liver failure and may need a liver transplant.
  6. Hematology/Oncology—Hematologist/Oncologists see patients with blood disorders and cancer.  These two sub-specialties are often combined, and Hematologist/Oncologists will usually see patients with blood disorders like anemia (low blood count) or cancer – such as breast, lung, and colon.  These doctors are not surgeons.  If a cancerous tumor needs to be surgically removed, this type of doctor will not perform the surgery.  If required, the Hematologist/Oncologist will typically administer the chemotherapy to treat cancer.  Often people with cancer see multiple types of doctors, and the Hematologist/Oncologist is just one of them.
  7. Nephrology—Nephrologists are kidney doctors.  They treat patients that have partial kidney damage (referred to as renal insufficiency) and kidney failure.  When a person has kidney failure, they may require dialysis to control the electrolytes (sodium, potassium, and calcium), water and waste products in their bodies.  Nephrologists are the doctors that manage the dialysis.  Another type of kidney doctor is a Urologist, but this specialty is not part of Internal Medicine, and they treat different types of kidney problems—such as kidney stones.
  8. Rheumatology—Rheumatologists treat conditions called ‘Autoimmune Diseases.’  An autoimmune disease is when the body’s immune system attacks itself instead of an outside bacteria or virus.  Examples of autoimmune diseases are rheumatoid arthritis and lupus.  Autoimmune diseases often cause pain and swelling in the joints, so rheumatologists are also joint experts and treat various joint conditions (e.g., gout).  However, rheumatologists are not surgeons, and they typically do not see patients that have joint injuries from sports or overuse—Orthopedic Surgeons usually see those types of patients.
  9. Allergy/Immunology—Allergist/Immunologists perform allergy testing to see what substances or foods a person may be allergic to (e.g., pollen, mold, nuts). They administer allergy shots to desensitize a person to those substances, making their allergies less severe.  They can also treat immune deficiency conditions. These are rare conditions where the body’s immune system is under-functioning.
  10. Infectious Disease—Infectious Disease doctors treat chronic and severe infections.  Common infections that these doctors treat are HIV/AIDS, bone infections and severe skin infections.  Fortunately, most infections that people have are short-lived, mild and are usually handled by their primary care physician—not an Infectious Disease doctor (e.g., strep throat, sinus infection).
  11. Geriatrics—Geriatricians are doctors for the elderly.  There is not a specific age where a person should start seeing a geriatrician, but these doctors typically see patients that are age 80 and above.  They specialize in helping people with dementia (Alzheimer’s and other types) maintain their quality of life and are good at coordinating the many medications that the elderly take—preventing drug interactions and minimizing side-effects.  Geriatricians may visit nursing homes to see their patients or even make house calls.

How do you relate these sub-specialties of internal medicine to listings on an insurance website?

If you look up a doctor and the website lists two specialties:

  • Internal Medicine and Pulmonology (then this doctor is a Pulmonologist, not a General Internist and a Pulmonologist)
  • Internal Medicine and Cardiology (then this doctor is a Cardiologist, not a General Internist and a Cardiologist)

In these examples, these doctors have gone on to specialize in Pulmonology or Cardiology, and they are not a General Internist or primary care physician (PCP).

  • If you are looking for a General Internist or PCP, then the doctor listed on the insurance website needs to indicate only Internal Medicine with no additional specialty listed.

Avoid confusion when looking for a Primary Care Physician

At Alight, our Health Pro Consultants deal with employees who face this challenging situation. They may have tried to look up a PCP on the insurance website, and when they visit the office, they learn that the doctor is actually a cardiologist. As a result, they have wasted their time and now need to find another doctor.

With healthcare navigation services like those from Alight, having a good understanding of the different sub-specialties, you can increase the likelihood of finding the right kind of high-quality doctor from the start.

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