Diabetes in Dogs
Written by Shula Berg BVSc CertAVP(GSAS) GPAdvCert(SASTS) MRCVS
Clinically reviewed by Elizabeth McLennan-Green BVM&S CertAVP(SAM) MRCVS
Table of Contents
Diabetes causes levels of glucose (sugar) in the blood to be persistently high. Normally when blood glucose levels increase, the pancreas releases a hormone called insulin which adds in a number of ways to lower the blood glucose and prevent it from getting too high. In most cases of canine diabetes, the pancreas stops producing insulin, meaning the body can’t regulate glucose levels. Less commonly, the pancreas makes insulin, but the body does not respond to it.
Any dog can develop diabetes; however, it is most common in middle aged to older dogs. It occurs more often in some breeds, such as Miniature Schnauzers, Miniature Poodles, Yorkshire Terriers and Samoyeds, suggesting there could be a genetic link. It is also seen slightly more often in dogs with a history of pancreatic disease (such as pancreatitis), or with other endocrine conditions such as Cushing’s disease.
The most common symptoms of diabetes are increased thirst and urination, weight loss, and often increased appetite. Diabetic dogs are more prone to cataract formation, which can affect the vision.
Eventually, lack of insulin prevents the body using glucose for energy. Instead, fat is metabolised, which releases molecules called ketones. These are harmful and, if they accumulate, causing a condition called ketoacidosis. Symptoms of ketoacidosis include vomiting, inappetence, weakness, and sweet-smelling breath. Ketoacidosis can make dogs very suddenly unwell and is more common in undiagnosed diabetics.
A thorough history and clinical examination will often raise a strong suspicion of diabetes. Several tests are then used in combination to confirm the diagnosis and guide treatment:
General blood tests
These will measure blood glucose as well as checking the liver, kidneys, protein levels, and blood cells. They screen for other conditions that can cause similar symptoms to diabetes or occur at the same time.
Diabetic dogs will have high levels of glucose in their urine. They may also have ketones present, especially if they are ketoacidotic. Diabetic dogs are prone to urinary tract infections so your vet may advise culturing the urine.
A single high glucose reading is not enough to confirm diabetes; we must be sure there is persistently high glucose. Concentration of the protein fructosamine reflects glucose levels over the previous two weeks. Fructosamine is measured at an external lab, so treatment is sometimes started before results are available, especially in unwell animals.
Diabetes is treated by injecting synthetic insulin once or twice daily. This needs to be done every day for the rest of the dog’s life. It is important that both mealtimes and insulin injections are regular, and that all family members who look after the dog understand the treatment required.
Dogs who are bright and well at diagnosis can often be managed as an outpatient. Dogs who are unwell, especially if ketoacidotic, often need hospitalisation. It can be very challenging to stabilise a dog who is not eating at the time of diagnosis, as regular meals are essential for accurate glucose control. As a result, it is not uncommon that unwell dogs remain in hospital for 4-7 days after diagnosis.
It is important to emphasise that treatment of diabetes is lifelong and can therefore be both costly and time-consuming. Managing a diabetic dog is a big commitment, and it’s important to consider this before embarking on treatment. Your pet will need a very regular medication and eating regime, which can be a challenge. Regular visits to the vet are very likely, as monitoring is needed to ensure the right insulin dose, and this process cannot be rushed. Furthermore, there may be other conditions that need to be managed at the same time. For some, euthanasia may be a fair option at point of diagnosis.
Diabetes in dogs has a reasonable to good prognosis. Most dogs respond well to treatment, although it’s important to note that stabilisation can take many months. A small number of dogs do not respond well to treatment and struggle to stabilise; these dogs sadly have a more guarded prognosis for long-term success.
A stable routine is key to successful management, however, even well controlled diabetics can have a changing response to medication over time and are at risk of becoming unstable. Periodic monitoring is therefore needed, even for the most stable patients. It is not uncommon for diabetics to require occasional periods of hospitalisation during their lives, as simple conditions such as a gastrointestinal upset can disrupt glucose control.
Please note that the content made available on this webpage is for general information purposes only. Whilst we try to ensure that at the time of writing all material is up to date and reflects industry standards, we make no representation, warranties or guarantees that the information made available is up to date, accurate or complete. Any reliance placed by yourselves is done so at your own risk.
Page last reviewed: 16th January 2024
Next review due: 16th January 2026