What is Diabetes Mellitus?
You’ve probably heard of a pancreas before, but not many people know about its functions in humans let alone animals. So, what does it do?
The pancreas, which sits amongst the stomach and small intestine, performs two main functions: the secretion of digestive enzymes into the small intestine to aid in digestion of food, and secretion of hormones into the bloodstream to regulate blood sugar levels.
Body cells only function normally with a constant supply of glucose, the body's primary fuel. Glucose is readily available in the bloodstream, but it is the hormone that the pancreas secretes that ensures that blood glucose enters the cells. This hormone is insulin, which essentially acts as a key to unlock the cell door to allow glucose in.
Key point: in a diabetic animal, either there is no key to unlock the door (insulin isn’t produced) or the key doesn’t work properly (insulin is produced but the body cells cannot use it correctly)
Most dogs have insulin dependent diabetes (no insulin produced) and most cats have non-insulin dependent diabetes (insulin is produced but the body doesn't respond to it). Diabetes in cats is often referred to as insulin resistant diabetes.
Without the insulin mechanism working, the body cells don’t receive enough glucose from the blood and as a result, we see a number of clinical signs/symptoms:
Constant hunger (polyphagia); Because the cells don’t receive a good supply of glucose, the body is fooled into thinking it is starving despite having high blood glucose levels. The body begins to break down fat, proteins and starch (a normal response in starvation). Normally, blood glucose levels are controlled; with this mechanism not functioning correctly, lots of glucose is passed through the kidneys into the urine (normally no glucose is filtered into the urine by the kidney). When glucose is lost this way, it pulls water with it causing excess urination (polyuria) and a result excess thirst (polydipsia) as the body tries to keep up with fluid loss.
Key Symptoms / Signs of Diabetes Mellitus
- Excessive eating
- Excessive urination
- Excessive drinking
- Weight loss
Other Signs / Symptoms may include
- Reduced appetite
- Tiredness / Lethargy
Key Point : if your pet is excessively drinking and/or excessively peeing and/or excessively eating but cannot put on weight, then please see your veterinarian.
There are a number of conditions that can cause these signs, so your vet cannot assume your pet is diabetic at this stage.
How Does Your Veterinarian Diagnose Diabetes Mellitus?
If you visit your veterinarian because of concerns of any of the above, they will almost certainly want to rule out diabetes mellitus. The following tests may be performed to help make a diagnosis
Blood tests should always be carried out to get a picture of overall organ function and internal health. The standard tests are a CBC (Complete Blood Count) and a Biochemistry Profile. Your veterinarian will be looking for evidence of dehydration and elevated blood glucose (although diabetes mellitus cannot be assumed from this alone as blood glucose can be high with stress and if your pet has recently eaten)
Urine Tests (Urinalysis)
Evaluation of the urine may show glucose, which is not present in the healthy animal. This is a key finding to help in the diagnosis of diabetes mellitus.
Urine white blood cells may be increased and blood present if an infection is active. Glucose helps the growth of bacteria, so urinary infections are common.
Ketones (which are produced by excessive breakdown of fat) can be detected in sick diabetic patients.
Fructosamine Blood Test
With a heightened suspicion of diabetes mellitus, your veterinarian will most likely take another blood sample to run a fructosamine test. Fructosamine is a protein that attaches itself to glucose in the blood. Therefore, a high blood fructosamine level correlates with a high blood glucose level. The great thing about this blood test is that it takes a few weeks for the fructosamine to get to a high level and so is a better indicator of high blood glucose being a constant issue (as in diabetes mellitus).
What Happens When Your Veterinarian Diagnoses Diabetes Mellitus?
In cats, because the most common form of diabetes mellitus is non-insulin dependent (i.e., the body cannot correctly use the insulin that is being produced), it may be necessary to rule out other conditions that are creating this “resistance” to the insulin being used properly.
If no other conditions are suspected or diagnosed, sometimes managing diet, managing your cat’s weight (if overweight) and/or oral medication can be enough to get things back on track. In most cases though, insulin injection treatment is required.
In dogs, because the most common form of diabetes mellitus is insulin dependent (i.e., the body doesn't produce enough insulin) insulin injection treatment will be required in most cases.
Your veterinarian (or support staff) will teach you how to give your pet injections under the skin and give you a detailed schedule on when to administer them. Most pets require injections twice a day, approximately 12 hours apart (after a meal) but this will depend on the type of insulin used, so it is important to follow your veterinarian's guidance exactly.
Giving injections may be intimidating at first, but most pet owners get the hang of it within a few tries, so please don't worry too much if the first few attempts don't go smoothly.
Top Tip : There is a lot of information about insulin dosages published on the internet, but please work closely with your veterinarian, as each diabetic patient is unique. There is no one solution fits all when it comes to this condition.
Weight management and diet play key roles in the treatment of diabetes, too, and your veterinarian will make recommendations. Your pet will need monitoring and treatment for life (in most cases) but diabetes is a manageable condition. Most pets go on to live long and happy lives after diagnosis if treated properly.