Internal Medicine

Our internal medicine specialists, Dr. Tobin and Dr. Elliott, have an in depth understanding of how your pets internal body systems function and are capable and experienced in diagnosing and treating the most serious diseases that affect these body systems.  Over many years in practice as an internal medicine vets, our specialists have built a reputation for applying their extensive knowledge in a kind and considerate manner.  


While your family veterinarian is qualified to handle many aspects of your pet's care, sometimes a specialist's expertise is needed. Just as your own primary care physician may consult with or refer you to a specialist for certain conditions, your primary care veterinarian may turn to a veterinary internal medicine specialist to help diagnose or treat  your pet’s especially complicated medical problems.


At Sunstone Veterinary Specialists, we are able to provide diagnostic testing and treatments right at our offices. Should your pet require CT or MRI, we can arrange an appointment for you at one of several regional hospitals.  Your pet will receive the highest level of care at Sunstone, for his or her condition, in a comfortable environment where you and your pet will feel welcome. 


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    Internal Medicine    Joshua Elliott, DVM, DACVIM (SAIM)         M   T   W   TH

    Internal Medicine    Regina Tobin, DVM, DACVIM (SAIM)          M   T   --    TH



Please call 503-505-7255 to schedule an appointment at Sunstone Veterinary Specialists with one of our internal medicine veterinarians, Dr. Joshua Elliott or Dr. Regina Tobin.






Internal Medicine

Joshua Elliott, MA, DVM, DACVIM Internal Medicine Specialist




Dr. Joshua Elliott is a board certified veterinary internal medicine specialist. This distinction means that he has undergone additional extensive training after completing a two-year master's degree in biology and four years of vet school. Becoming a Diplomat of the American College of Veterinary Internal Medicine requires a one-year internship and a three-year internal medicine residency followed by rigorous examinations in which he was required to demonstrate his expertise in internal medicine.  




"l love getting to know my clients and patients. l know l can make a difference in the quality of my patients lives." - Josh Elliott



Internal Medicine

Regina Tobin DVM, DACVIM

Internal Medicine Specialist


Dr. Regina Tobin attended veterinary school at Cornell University. Following her graduation in 1994, she completed a one-year internship in small animal medicine and surgery at Angell Memorial Animal Hospital in Boston. Dr. Tobin then spent a year in general practice in the Boston area before starting her small animal internal medicine residency at UC Davis. She became board certified in small animal internal medicine in 1999. Dr. Tobin has worked in clinical practice in Oregon since 1998, with the exception of a two year period when she worked as a consultant for a major diagnostic lab. 



"I honestly just love animals, even the ones that are trying to bite me! I love the challenge of determining what is wrong with my patients, developing a plan that helps them, addressing my client's concerns and doing my utmost to provide a positive outcome." - Regina Tobin






Internal Medicine Patient Management and Care


  • Acute Heart Failure, Arrhythmias and Cardiac Emergencies
  • Addison’s Disease
  • Complicated and Atypical Cushing’s Syndrome
  • Complicated Diabetes Mellitus
  • Chronic and Acute Kidney Failure
  • Chronic Gastro-Intestinal Diseases
  • Infectious Gastro-Intestinal Disease
  • Inflammatory Bowel Disease
  • Exocrine Pancreatic Insufficienc
  • Pancreatitis
  • Liver Disease
  • Immune-Mediated Diseases
  • Hemolytic Anemia
  • Hepatitis
  • Joint Disease
  • Systemic Lupus Erythematosus
  • Thrombocytopenia
  • Medical Management of Portosystemic Shunting
  • Persistent Respiratory Disease
  • Chronic Recurrent Pneumonia
  • Feline Asthma
  • Chronic Bronchitis
  • Seizures and Neurologic Emergencies
  • Treatment and Diagnostics for Other Endocrine Disorders
  • Complicated Thyroid Diseases
  • Diabetes Insipidus
  • Hypo/Hyper Parathyroid


Internal Medicine Tests and Procedures

After reading through your pet’s complete medical history, meeting with you and performing a thorough examination, your pet's internist will discuss their findings with you.  At that time he or she may recommend more diagnostics (tests and procedures). These diagnostics will help give them a more complete picture and provide necessary information to accurately assess your pet’s current condition. Our specialists will carefully choose tests and procedures to recommend that will provide the most information and be the most beneficial to assessing your pet’s current condition. The diagnostics recommended are based on the problems identified.  While every patient has an examination and consultation, election of further diagnostics are based on finding a plan that best fits each family . Proceeding with any additional tests and procedures is always at the discretion of the pet’s family.



Examination and Consultation

Prior to your pet’s initial consultation, your pet's internal medicine doctor will review your pet's entire medical history.  This includes a review of all medical records and previously performed tests. Our Internists always perform a thorough physical examination of their patients during their consultations.  This is a very important step in formulating a diagnostic and treatment plan for your pet.  


Our internal medicine specialists will always thoroughly review their findings with you and make recommendations to you to manage and care for your pet’s health.  Each patient and each family is unique.  Rest assured, these doctors and their teams will work with you to put together a plan that will address your pet’s needs.


Blood Tests and Urinalysis

Blood and urine tests are common tests that are often recommended when a pet is ill. Samples are easily collected, and results of these tests give a broad understanding of organ function and general health. Basic blood and urine panels are common starting points. Specialized blood and urine testing may also be recommended based on these results and on your pet’s overall signs.


Diagnostic Imaging (X-rays and Ultrasound)

Diagnostic imaging creates pictures of the internal organs and body which provides additional information. These images go beyond what can be identified from a physical exam alone. X-ray imaging and ultrasound are the most common imaging modalities used to evaluate the internal organs in veterinary patients. Ultrasound provides more in depth and detail oriented information, but does not provide the overview that x-rays allow. Ultrasound also does not image healthy bone, lung tissue or other gas filled organs while x-ray does. Because of these differences, x-rays and ultrasound are frequently recommended in the same patient to gain the maximum amount of information.



Endoscopy is a group of procedures that allows for minimally invasive evaluation of the interior of a hollow organ or cavity of the body with an instrument called an endoscope. Endoscopes come in a variety of sizes and are either a rigid or flexible tube with a tiny camera and a light source that projects images from inside the area being examined onto a video screen for the doctor to visualize. Common areas examined with endoscopy include the gastrointestinal tract, (stomach/small intestine or large bowel), airway (bronchoscopy), bladder (cystoscopy), nasal passages (rhinoscopy) and joint endoscopy.  Gastrointestinal endoscopy allows us to visually inspect the wall of the stomach, small intestine or colon to identify irregularities such as ulcers, masses, polyps, strictures or areas of inflammation.  Biopsies are generally collected from any affected areas.


Joint Taps

Infectious or immune-mediated types of arthritis can cause painful swellings of the joints, lameness and difficulty walking. A variety of systemic diseases can influence and affect one joint or multiple joints. Clarifying between the different possible causes of joint disease is critical to guiding treatment. If your pet is having signs suggestive of joint disease, arthrocentesis (“joint tap”) may be recommended. This would be to obtain a fluid sample for lab evaluation.


Bone Marrow Aspirates and Core Biopsies

Red blood cell, white blood cell, and platelets all grow and develop in the bone marrow of the body. Evaluation of the bone marrow can allow interpretation of changes in these numbers. Cancer, infectious diseases, and other disease processes can specifically infiltrate or damage the bone marrow.  Any of these can be life-threatening because of secondary damage to the blood cell lines. Bone marrow aspirates and core biopsy helps guide treatment and therapy to each patient.


Management of Addison’s Disease

Addison’s disease is a deficiency in hormone(s) that are produced by the adrenal glands. Typically there are deficiencies of cortisol and mineralocorticoid hormones. Some patients will initially experience an “Addisonian crisis.” A fraction of cases known medically as “Atypical Addison’s disease”  result from a deficiency in only cortisol. Addison’s disease can be easily managed with supplemental hormone(s) following diagnosis. Both Dr. Elliott and Dr. Tobin can provide guidance in the diagnosis and treatment of these patients.


Management of Chronic Gastrointestinal Disease

The mouth, esophagus, stomach, intestine, and pancreas are all organs that make up the digestive tract. Vomiting, diarrhea, poor appetite, weight loss, drooling, straining to defecate, and blood or mucous in the stool are all symptoms of stomach and intestinal disease. Eating inappropriate things can cause acute but generally temporary signs, however, chronic or ongoing symptoms should be investigated. Referral to an internal medicine specialist should be recommended for additional testing and more advanced care.


Management of Complicated Diabetes Mellitus

Diabetes mellitus is a common disease defined by deficiency of the hormone insulin. Most dogs and cats are easily managed with twice daily insulin injections and dietary modifications. Concurrent disease processes can cause production of hormones that block and influence insulin function. These types of counter regulatory hormones can make diabetic control difficult. If your pet has diabetes but is not well controlled, referral to Dr. Elliott or Dr. Tobin for further testing and evaluation may allow additional options for better control.


Management of Cushing’s Syndrome

Cushing’s Syndrome is a group of diseases that cause an overproduction of one of the adrenal hormones, cortisol. Many patients who develop Cushing’s syndrome are easily regulated and managed with medication. However, some patients with Cushing’s syndrome have concurrent disease processes that lead to poor regulation and on-going signs. When more than one disease is present, it can be challenging to identify and difficult to guide therapy. Our internists specialty and training have prepared them to address these types of complications.


Management of Immune-Mediated Disease

“Auto-immune” or “immune-mediated” diseases occur when the immune system starts to attack one’s own body inappropriately. This can lead to severe organ and tissue damage. Signs include fever, lethargy, poor appetite, joint pain, joint swelling and a variety of others. The most common of these diseases is the damage/destruction of red blood cells, platelets, joints and the entire body. Diagnosis is challenging. Treatment is long term, sometimes life-long, so ongoing management by an internal medicine specialist may be recommended.  Complicated cases requiring multiple medications and additional therapies can still provide prolonged quality of life for many poorly responding cases.


Management of Kidney Failure

Kidney failure is a common disease that occurs in dogs and cats. Acute kidney failure is often caused by toxins, infections and other sudden impacts. It occurs quickly and can sometimes be reversed with treatment of the underlying cause. Chronic kidney failure is the destruction of kidney tissue over time and is permanent. However, it can be managed with appropriate therapy. There are up to a dozen different types of therapy that can be instituted to try and delay further kidney damage/destruction. Dr. Elliott and Dr. Tobin are well versed in these options and can help guide recommendations on your pet’s individual needs. The goal of this treatment regimine is to stabilize the disease and improve quality of life.


Management of Liver Disease

The liver works to filter and remove harmful toxins and by-products of digestion. Even relatively “simple” abnormalities of the liver can cause severe and life-threatening complications. If your pet is icteric, jaundiced or has blood test changes that are concerning for liver disease, referral for additional diagnostics and long-term therapy and recommendations may be beneficial.


Management of Other Endocrine Disorders

Endocrine diseases are hormonal diseases. This is a broad category of disease defined by secretion of hormones into the bloodstream to influence metabolism, growth, development, and organ function. Common endocrine disorders, including diabetes mellitus and diseases of the adrenal glands, are discussed elsewhere on this page. Thyroid disease, parathyroid disease and diabetes insipidus are additional hormonal abnormalities that can occur in veterinary medicine. Parathyroid disease, diabetes insipidus and some other rare endocrine diseases can be very difficult to diagnose or control. Referral to Dr. Elliott or Dr. Tobin may be suggested.


Management of Persistent Respiratory Disease

The nose, nasal cavity and sinuses, larynx, pharynx, trachea (windpipe), bronchi, and lungs are all organs that make up the respiratory tract. Signs of respiratory disease include coughing, nasal discharge, sneezing, reverse sneezing, “voice” change, increased respiratory effort, and “snoring” or noisy breathing. When these signs are persistent and have not responded to medications other therapies, further investigation is warranted. It may be recommended that your pet be evaluated by an internal medicine specialist for advanced diagnostics and chronic care.


Nutrition and Placement of Feeding Tubes

Nutrition is an important part of daily care that we provide for our pets. Many healthy pets thrive on almost any balanced and complete, commercial diet. Special prescription diets, dietary supplements and feeding tubes (in extreme circumstances) can be recommended to assist with the management of a variety of chronic disease processes. Dr. Elliott and Dr. Tobin are well-trained in veterinary nutrition and can provide recommendations. If necessary, consultation with a board-certified veterinary nutritionist can be arranged.