Meet the Veterinary Specialists: The Internist
April 25, 2005
Editor's Note: As people have become more health-conscious, and bonds between humans and their pets have deepened, the demand for veterinary specialties such as dermatology, behavior, pathology, and surgery has risen. The following is part of a series exploring these specialties and the University of Illinois veterinarians who practice and teach them.

Internal medicine specialists, or internists, are the "jacks of all trades" of both human and veterinary medicine. They treat a broad range of body systems and a diverse array of diseases. Internal medicine may be considered the hub of specialties, since it deals with conditions that overlap with all other specialties.

The American College of Veterinary Internal Medicine includes the subspecialties of cardiology, neurology, and oncology as well as general internal medicine. According to Dr. Steven Marks, veterinary internist and chief of small animal medicine at the University of Illinois Veterinary Teaching Hospital in Urbana, general internists have specialized training in all the organ systems in the body cavity and work closely with other specialists in the areas of dermatology, cardiology, neurology, oncology, and surgery when cases require this expertise.

Internists address diseases of the kidney, liver, respiratory system, gastrointestinal system, urogenital system, endocrine system (hormones), and immune system, as well as blood disorders and all infectious diseases.

With their broad range of medical training, internists are often the first specialists to see confounding or serious cases referred by general practice veterinarians. While some generalists have the equipment and skills to perform advanced diagnostics, such as endoscopy and ultrasonography, others don't and may refer patients to an internist, especially in cases where the source of a problem is unclear. Internists have broad knowledge of the body systems and disease and have the skills to perform a very thorough evaluation.

All board-certified internists have had a year-long internship or equivalent practice experience and 2 to 3 years of formal residency training in addition to the 4-year veterinary degree. This training is almost identical to human physician training. Specialists also have more specific experiences since they see advanced and unusual cases on a more regular basis.

Since internists deal with diverse diseases, they work closely with other specialists. For example, the endocrine disease diabetes can predispose an animal to cataracts, so an internist may work with an ophthalmologist treat a diabetic patient. In addition to treating serious or unusual cases of disease, internists also play a central role, along with critical care specialists, anesthesiologists, and surgeons, in emergency and critical care medicine.

Internists also see many geriatric patients, since older pets often have multiple, overlapping conditions involving multiple organ systems.

Dr. Marks explains that internists often consult other veterinarians long-distance regarding complex cases. "Being in university setting, we're not just here to see cases, but to also help other veterinarians with their cases. The specialists provide consultations for general practice veterinarians from around the country who call with unusual cases." Dr. Marks and his colleagues regularly consult with practitioners via phone, faxed lab results, and email, providing additional expertise for clients who cannot travel to the hospital in Urbana.

The American College of Veterinary Internal Medicine currently has 800 members, and the University of Illinois currently has three residents in its internal medicine training program.

For more information about the veterinary internal medicine, cardiology, neurology, and oncology specialties, visit the Web site of the American College of Veterinary Internal Medicine at and click on "Pet owners & Public."

An archive of pet columns from the University of Illinois College of Veterinary Medicine is on the Web at