Internal Medicine

Internal medicine is the investigation and treatment of anything ‘inside’ the body. This means digestive disorders (gastroenterology), hormonal diseases such as diabetes and thyroid disorders, respiratory disease such as asthma, diseases of the kidneys and bladder (urology), and diseases of the immune system.

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What makes us unique

Our highly trained team of specialists with experience from around the world operating in one of Australia’s leading veterinary hospital facilities. We are one of the few facilities able to perform radioactive iodine treatment for thyroid cancer in dogs, as well as for treatment of hyperthyroidism in cats. We have access state of the art equipment including options for minimally invasive interventional techniques.

Services we offer

We offer a range of internal medicine referral services, including:

  • Investigating, diagnosing and treating a wide range of medical cases in cats and dogs.
  • We provide specialist advice and management for pets with cancer (see Oncology), respiratory disorders, blood disorders, hormonal disease, digestive and urinary disorders.
  • We only see animals that are referred by their regular veterinarian and offer services throughout the week to animals throughout Victoria and beyond.

Our dedicated Internal Medicine team are able to coordinate with our other specialist services, all of whom can assist in providing the best comprehensive care to make the best decisions for you and your pet.

See also: Small Animal Medicine referral services – What we offer


Hyperthyroidism in cats is a disease caused by the over-production of thyroid hormone by the thyroid gland. It is usually caused by a benign tumour that grows in the gland, and this may occasionally be felt as a swelling on your cat’s neck. The disease causes a variety of symptoms, including hyperactivity, weight loss (occasionally weight gain), excessive drinking and urinating, increased (often ravenous) appetite, vomiting and diarrhoea. If untreated, the disease will eventually lead to serious heart disease, kidney disease, emaciation and death. Your veterinarian will have confirmed the diagnosis of hyperthyroidism by using a blood test that measures the level of thyroid hormone in the blood, and referred you to us for treatment of the condition.

We have been using radioactive iodine to treat hyperthyroidism in cats since the late 1980’s. The treatment is extremely safe for your cat, it is not at all painful, and does not cause any serious side effects. It is considered the most effective way of treating this disease as 90-95% of cats are permanently cured with a single treatment, and is used by universities and veterinary specialist centres all over the world. It is also one of the ways that hyperthyroidism is treated in humans. We generally see appointments on Mondays to evaluate patient suitability for treatment and to discuss this in detail.

The treatment is simple, but because it involves the use of a radioactive compound, there are strict laws in Australia relating to how it is given and the subsequent management of the patient. Our facility is licenced to give this treatment. The radioactive iodine is given by mouth in a capsule by specially trained and licenced staff. We sedate your cat first to avoid any struggle (some cats don’t like taking medicines at all!) and to minimise the chance of accidental spillage of the radioactive iodine. We check carefully that the dose has been swallowed properly, and then the cat is placed in a cage in our special isolation room, here at the Clinic and Hospital. A radiation monitor is used to verify uptake of the compound by the thyroid gland.

By law, the cat must remain in isolation for at least one week following treatment and until radiation levels decline to a safe value. We usually treat on Tuesdays and your cat will be able to go home on the following Tuesday in most cases. The patient is checked regularly each day and is fed twice daily. You may supply your own tinned and/or dry food if your cat is a particularly fussy eater, but we provide good quality cat food and most patients have a very good appetite. We also provide water, bedding material and a litter tray, which is changed daily. If you do wish to provide any bedding, it will stay with your cat throughout their stay but it cannot be returned to you.

What to expect from your radioactive iodine appointment

You have been referred to U-Vet for radioactive iodine (also called radio-iodine or I131) treatment to treat your cat’s hyperthyroidism. Following is some general information which may be helpful prior to your appointment.

Before your appointment:
Treatments for hyperthyroidism (Carbimazole/Methimazole) must be stopped 5-7 days and prescription diet for hyperthyroidism (Hills y/d) must be stopped 3 weeks before radioactive iodine treatment. Other medications can generally be given as usual, but if you have questions please check with your regular veterinarian or call our direct line (see below).

Your appointment has been scheduled for a Monday morning, with treatment planned for the following day. Cats should be brought in a carrier. You can bring some familiar bedding and a light blanket or towel to cover the carrier, which will often help cats feel more comfortable during travel and veterinary appointments. If your cat does not get sick during travel then feeding them on the morning of the appointment is fine, and medications other than mentioned above can be given.

If your cat is currently taking any medication (other than routine parasite preventatives), please bring it with you. If your cat is on a particular diet, please let us know prior to the appointment so that we can check to see if we keep it in stock. If it is a diet we do not routinely stock, we may ask you to bring a supply for your cat. If your cat has a chronic medical condition which will require treatment during their time in hospital (e.g. diabetes) please call us prior to the appointment to discuss.

Please check in at reception and take a seat in the waiting room. One of the medicine nurses will show you to a consultation room for the appointment.

The consultation:
A final year veterinary student may start your appointment by taking a history (including asking questions about your pet and the reason for the visit, symptoms, current medications) and performing a physical examination. In most cases, we will have already received records from your regular veterinary clinic about your pet’s recent history, however it is important for us to ask these questions and examine your pet ourselves.

The student will then meet with the vet who will be taking care of your pet to discuss the history and physical examination with them, then the vet will come into the consultation room. The vet may ask additional questions if there are things that need to be clarified and will also perform a physical examination.

Each appointment is typically scheduled for one hour. If you have any time constraints please let our nurse know when you check in.

The vet will discuss the radioactive iodine treatment, including success rate, potential side effects, and cost. Students are involved in the care of pets treated at U-Vet, and are always supervised by a veterinarian.

A blood pressure check is usually performed as part of the initial appointment. In cats where there is concern for potential heart disease, for example because of a heart murmur or other abnormal heart sounds, an ultrasound of the heart may be recommended prior to radioactive iodine treatment. This procedure is not mandatory, but will help to determine if there is a greater risk with sedation or hospitalisation. This may require re-scheduling radioactive iodine treatment.

If you decide to go ahead with treatment, your cat will be admitted from your appointment for treatment on Tuesday. Cats are sedated for treatment and will be fasted from Monday night. The radioactive iodine is given in a capsule, and after it is given the cats are scanned to make sure the radioactive material is in their stomach.

After treatment, cats are kept in an isolation ward because they are slightly radioactive. They are checked twice daily for feeding, water changes and litter box cleaning, but cannot otherwise be handled during their time in isolation. They are typically hospitalised for one week. You are not able to visit your cat during their hospitalisation, but we will update you every day. If you bring bedding or toys, these can stay with your cat during hospitalisation but cannot be returned to you.

An appointment will be made for you to pick up your cat once the isolation period is over (normally on a Tuesday). A vet will meet with you and you will receive written notes. Handling precautions at home are required after treatment as the radioactivity takes some time to dissipate completely.
Precautions include limiting close contact time, so if your cat normally sleeps with you at night alternative arrangements may need to be made.
We also advise that children and pregnant women are not in contact with your cat for these two weeks.

Payment: Payment is due when your pet leaves the hospital. In cases where pets are admitted to hospital for procedures or for treatment, a 50% deposit is required at the time of admission. The vet will go through the estimated costs with you at the initial appointment and throughout hospitalisation. U-Vet does not offer payment plans, however, Vet Pay offers payment plans – approval is required.

If you have questions about your appointment, please call our direct line (03) 9731-2054. If it is not answered, please leave a message and we will return your call as soon as possible. In case of an emergency, please call the main reception on (03) 9731-2000 and choose option 1.

After discharge from the hospital

1. As your cat will still be excreting small amounts of radiation, we recommend that you limit close (less than one metre) and prolonged (more than 20 minutes per day) contact with your cat for another two weeks. That means limited lap time and not sleeping on the bed at night. This is particularly important for children and pregnant women, and we recommend that they have no contact with the cat during this time. You should also wear gloves to empty litter trays, and double bag any soiled litter before disposal. After the two weeks, you can return to handling your cat normally.

2. Please arrange for your regular veterinarian to check your cat and take a blood sample to check the thyroid hormone level ONE MONTH after discharge from here. This will allow us to check how the treatment has worked. Kidney function is checked at the same time. Transient low thyroid hormone levels are not uncommon initially. Some cats will also initially have high thyroid hormone but this returns to normal over a few months. Therefore, the final effect of treatment is decided at THREE-FOUR months. For most cats, the signs of hyperthyroidism usually resolve over the first few weeks at home. Most cats are cured by a single treatment, but 5-10% may require re-treatment and 2.5% of cats can need treatment for low thyroid hormone in the long term.

Is a diagnostic procedure that allows the assessment of some internal organs, via natural openings (such as the mouth or nose). An endoscope is a sophisticated fibreoptic camera, with which the surface of internal organs can be examined, photographed or videotaped.

Endoscopy is useful for diagnosing underlying disorders of the breathing system (such as nose bleeding or nasal discharge, coughing or breathing problems), digestive system (such as vomiting or diarrhea) or urinary system (such as urinary incontinence). In these instances, endoscopy may be recommended to you.

Endoscopy is a minimally invasive procedure, that is, there is usually only a very short recovery period from the procedure, and there are usually no surgical wounds or sutures. Your pet is often able to be discharged from the hospital within one or two days. In some instances, a preparation period before the procedure is necessary – we will advise you if that is the case.

To assure that your pet is comfortable during the procedure, anaesthesia is required. Once your pet is asleep, the endoscope is introduced into the mouth, nose or urinary tract, and passed along the natural passages, such as trachea (windpipe), oesophagus (food pipe) or urethra (urine tube) to reach internal organs, such as the nose, stomach, lungs or urinary bladder.

During the procedure, we will inspect the internal surface of the respective organs, and note abnormalities, such as ulceration, thickening or masses, foreign bodies, swelling or abnormal discharge. In many instances, we are able to remove foreign bodies. We will often take biopsies or fluid samples from the respective organs. These samples are sent to the laboratory services (microbiology, cytology and/or histopathology), and may help us to diagnose the underlying disease in your pet. The time to receive an answer from the laboratory (turn-around-time) may vary based on the sample that was taken and the tests requested, but is usually between 2 and 4 working days.

In most cases there is minimal risk of complication from the procedure. In the case of nasal biopsies, some sneezing or bleeding from the nose is common but usually improves within 1-3 days. In the case of airway investigations (bronchoscopy and bronchoalveolar lavage) there may be some increased coughing for a few days

Is the endoscopic examination of the airways (i.e. larynx (or voicebox), trachea (or windpipe) and bronchi). After the inspection of the airways, we often taken fluid samples called BAL (see below).

During or after bronchoscopy, a small amount of sterile fluid is flushed into the airways. It will mix with the airway secretions. This “mix” is then aspirated back. The sample is sent to the laboratory to identify microorganisms and cells within the sample. Results of this procedure may help to identify infection, inflammatory diseases (such as feline asthma), and sometimes neoplasia (cancer). Some pets cough more after bronchoscopy and BAL. The coughing usually improves within few days.

Is the endoscopic examination of the food pipe. This is often done in an attempt to remove foreign bodies (such as bones, fish hooks, stones or toys). This procedure may also be suggested if your pet is bringing up food repeatedly.

Is the endoscopic examination of the stomach and the first part of the small bowel. It may be recommended to remove foreign bodies in the stomach, or if your pet suffers from weight loss, vomiting and/or diarrhoea. During the procedure tissue samples are often taken.

Is the endoscopic examination of the urinary tract. This procedure may be recommended when your pet has urinary leakage, or has pain or discomfort when urinating. During this procedure, urine samples and/or tissue samples may be taken. In some instances, this procedure may be followed up directly by surgery. We would inform you before the procedure if we consider it likely that a surgical procedure will follow.


Is an advanced imaging procedure. It is similar to traditional radiographs, in that similar rays are deployed. However, compared to traditional radiography, CT is more sensitive. That is, it allows the detection of smaller structures, and it provides more detail of the specific structure. In addition, contrast agents may be injected to highlight certain structures and vessels. A powerful computer reconstructs the images obtained and allows construction of 3D images. Preliminary results are usually available shortly after the procedure, and the final report is often available within 24 hours.

CT can be useful in many different situations; we often suggest this procedure to obtain detailed information about structures in the nose, bones, chest or abdomen.

Your pet often requires sedation or anaesthesia during this procedure. We recommend sedation or anaesthesia because it will make your pet comfortable, and avoid artefacts that may arise when your pet moves. It also protects your pet, our staff and students from excessive radiation.

We work closely with the diagnostic imaging and anaesthesia services when performing CT.

This is another advanced imaging technique, which enables us to get very detailed information about internal structures and organs. MRI provides different information when compared to traditional radiographs and CT.

The technique utilizes the magnetic resonance of atomic nuclei, particularly protons (H+). Images are created by altering magnetic fields around the body, and recording the response of protons to these magnetic field changes. 2D or 3D images are constructed from the responses by a computer. The content of protons differs between individual organs; which enables us to identify normal organ borders and abnormalities.

MRI is very useful when investigating diseases associated with the brain and spine, muscles, heart or abdominal organs. Preliminary results are usually available shortly after the procedure and final reports are often available within 24 hours.

During MRI, your pet has to be completely still, and handling or holding of the patient in the machine is not possible. MRI is also associated with considerable noise. To allow your pet to be comfortable and to obtain great images, anaesthesia is required. Your pet will be monitored carefully during this procedure.

We work closely with the diagnostic imaging and anaesthesia services when performing MRI.

Abdominal ultrasound involves using an ultrasound machine to see the organs within the abdomen via sound waves. The animal’s hair over the abdomen is clipped so a good image can be obtained. Alcohol is used to clean the skin, followed by covering the abdomen with gel, which helps transmission of the sound waves. The probe of the ultrasound is gently pressed again the skin of the abdomen. This procedure is performed by specially trained veterinary radiologists at our hospital. Dogs and cats are usually sedated for this procedure and gently restrained as required.

Abdominal ultrasound is used to investigate disorders of all organs within the abdomen. Abdominal ultrasound is often used to investigate abdominal pain, vomiting, diarrhoea, fever, anorexia, abdominal masses, organ enlargement, and abdominal fluid. Ideally animals are fasted (no food, water only) for 12 hours before ultrasound so gas and food in the stomach don’t interfere with the images.

The ultrasound scan takes about 30-60 minutes and preliminary results are known at the end of the scan, with the final report usually available within 24 hours. Abdominal ultrasound is a fast, safe, non-invasive and cost effective way to examine the abdomen without surgery or x-rays.

Abdominal ultrasound can also be used to help direct a small needle through the body wall into an area of interest to collect cells and / or fluid. These samples are then examined by a veterinary pathologist, and cell examination (cytology) and fluid analysis results are usually known within 24 hours. Samples for bacterial growth usually take 2-4 days to return. This is a safe, fast, minimally invasive way to help establish a diagnosis with few and rare complications.

Echocardiography involves using an ultrasound machine to see how the heart is working via sound waves. Small patches of hair over both sides of the chest and sternum are clipped so a good image can be obtained. The skin over the chest is cleaned with alcohol, before gel is applied to help transmission of the sound waves. The probe of the ultrasound is gently pressed against the skin of the chest and two dimensional images of the heart in black and white are produced. This procedure is performed by specially trained internists or radiologists in our hospital. Dogs and cats are usually not sedated for this procedure, and gentle restraint is used as required. Colour is used to help determine the direction and speed of blood flow within the heart.

Echocardiography can provide a wealth of helpful information, including the size, shape and function of the heart and valves, pumping and relaxation capacity, and the location and extent of any tissue damage. Echocardiography is used to investigate heart murmurs, coughing, congenital heart defects, congestive heart failure, and abnormal heart rhythms. Echocardiography is sometimes used to monitor the treatment of heart disease. It is a safe, noninvasive test with no known risks, contraindications or side effects. Echocardiography usually takes 30-60 minutes and preliminary results are known at the end of the scan, with the final report usually available within 24 hours.

The bone marrow lies in the central canal of bones and produces the cells of the blood like red and white blood cells. Bone marrow examination is helpful in the diagnosis of disordered of bone marrow such as when there is non-regenerative anaemia (low red cell counts), low white cell counts, low platelet counts and unexplained high calcium levels.

Bone marrow aspiration or biopsy involves collection of tissue samples from within the bone marrow. Animals are either heavily sedated and local anaesthetic is used, or they are fully anaesthetised, so that no pain is felt. A special needle is used for collection after inserting through the skin and bone into the central marrow cavity. This is a sterile procedure and the area is carefully prepared prior. The humerus (upper arm) is the usual site of collection. A small stich or tissue glue is used to close the small skin incision. The procedure usually takes about 5-15 minutes.

The bone marrow fluid or tissue is sent to a veterinary pathologist for analysis along with a sample of circulating blood. Aspirate results are usually available within 24 hours, and biopsy results take usually 2-4 days to return. There are few contraindications to this procedure, even in the presence of bleeding disorders. While mild discomfort is common after collection (and can be successfully managed by pain relief), serious complications are extremely rare.

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