What is Diabetes Mellitus?
The cells of the body require a sugar known as glucose for food and they depend on the bloodstream to bring glucose to them. The cells need insulin to absorb and use this glucose. Insulin is produced by the pancreas. When the body does not have enough insulin, glucose levels in the blood stream become extremely elevated (because it can’t move to cells) leading to production of life threatening ketones. This is Diabetes Mellitus.
The main clinical signs of diabetes mellitus are:
- Excessive eating
- Excessive drinking
- Excessive urination
- Weight loss
Diagnosis can be made at the time of consult with a few inhouse pathology tests however often your vet will request a broader blood panel including a few specific additional tests to determine the diagnosis. Quite frequently a secondary symptom of Diabetes Mellitus is a urinary tract infection so we may also request a culture of your pet’s urine.
Type I and Type II Diabetes Mellitus
In humans, diabetes occurs in two forms: Type I and Type II. These are also referred to as juvenile onset and adult onset diabetes, or insulin dependent and non-insulin dependent diabetes. In short, Type 1 is the type where the pancreas produces no insulin at all, and in Type 2 the pancreas produces some insulin but not enough. Virtually all dogs have insulin dependent diabetes and must be treated with insulin. Most cats have non-insulin dependent diabetes. This means cats have the ability to resolve their diabetes if the pancreas starts producing insulin. However, they will need injections and diet control at least initially.
What happens once a diagnosis is reached
Once a diagnosis is achieved your vet will discuss with you the treatment and monitoring processes. Your pet will be started on twice daily insulin injections and whilst this may initially seem daunting, it is quite achievable in most cases. Whilst some pets may gain control of their Diabetes quite quickly (e.g. over a few weeks), others may take longer and require more intense monitoring so it’s important you discuss with your vet all possible outcomes and the cost of undertaking management of a Diabetic patient before commencing treatment.
Some Diabetic pets may initially present with ketoacidosis which is when excessive fat metabolism occurs due to poor glucose regulation leading to the production of ketones causing severe metabolic derangement. Patients that present in this state require around-the-clock intensive care to stabilise their glucose and electrolyte levels before proceeding to general diabetic treatment.
Once stablised all diabetic patients will need to start on twice daily subcutaneous injections. Usually the pet spends the first 24-48 hours of treatment in hospital so vets can monitor their glucose levels and see their response to the insulin treatment. Following this the patient is discharged and owners are shown how to provide ongoing care. The most common cause of poor diabetic control is inappropriate administration of insulin by owners so it’s important you listen to your vets’ instructions carefully and ask questions.
Insulin must be purchased from the vet. You will also need syringes and a bottle of insulin to begin home treatment. Insulin syringes are marked in insulin units so the insulin syringes must match the insulin concentrations (either U-100 syringes for 100 unit/cc insulins or U-40 syringes for 40 unit/cc insulins.) Always double check these numbers whenever you receive more supplies. Insulin and supplies can be ordered from your vet regularly (without having to bring your pet in each time) however you will be required to have regular rechecks which likely will include blood glucose monitoring.
Never alter the insulin dose recommended by your vet unless specifically told to do so. To determine whether dose adjustments are needed (or if a different type of insulin is more appropriate), your pet will need a glucose curve where blood sugar levels are monitored every 2 to 4 hours or so for 12 to 24 hours. This kind of testing tells the doctor how long the insulin injection is lasting as well as what the lowest and highest glucose levels of the day are. It is important to find out when your pet’s curve is due. Often in the beginning, it takes several dose selections and several curves before the right dose is determined.
Some pets do not cope well with a full day of hospitalization for glucose monitoring so an alternative test may be recommended called a Fructosamine test. This gives us an idea of diabetic control over the previous few weeks.
Ketostix are used to detect ketones in urine and can be obtained at any drug store. If it is not difficult to access your pet’s urine, a first morning test is helpful. Remember, finding ketones occasionally is not a problem but a positive dipstick three days in a row is a criterion for a vet visit.
Some clients choose to monitor blood glucose levels at home or even perform entire curves at home. This is achievable with a home glucose kit and pricks to the paw or ear. Your vet can discuss this option with you.
Your pet will probably require regular monitoring, the frequency of which is based on how well controlled they are and whether they are exhibiting any symptoms. Even the well-controlled diabetics should have a blood glucose curve performed every 6 months.
Bring your pet in for a recheck and glucose curve if your pet:
- seems to feel ill
- is losing weight
- has a ravenous appetite or loses its appetite
- seems to be drinking or urinating excessively
- becomes disoriented or groggy
- has ketones in the urine for three days in a row.
It is important for diabetic pets to have their teeth cleaned annually. Dental tartar seeds the body with bacteria and when blood sugar levels run high, infections in important organs can take root. The kidneys and heart are particularly vulnerable. This clean is performed under general anaesthetic.
If your pet appears wobbly or “drunk”, the blood sugar level may have dropped too low. This occurs after an insulin overdose. First try to get your pet to eat. If the pet will not eat, administer 1 tablespoon of honey or sugar-water. If no improvement occurs, immediately see your veterinarian for emergency treatment. When your pet is more stable, a glucose curve will be needed to determine why this happened and what a more appropriate insulin dose might be. In severe cases insulin shock may present as full body tremors or even seizures. This is an emergency and you should take your pet to the vet immediately for treatment.
Occasionally control of Diabetes is difficult and an underlying cause for this may include:
Improper administration of insulin. Your vet will get you to demonstrate how you administer the insulin and discuss how it is stored and drawn up.
Rapid insulin metabolism. Insulin wears off quickly in some animals. Your pet may require a different type of insulin or a second injection during the day or even additional injections during the day.
Insulin overdose may lead to elevated glucose levels (and clinical signs of diabetes mellitus). In this situation, too much insulin brings the blood glucose too low and other hormones respond to bring it back up (and generally over-do it).
Steroid administration (such as prednisone, prednisolone, etc.) will interfer with insulin.
Progesterone, a female hormone, also interferes with insulin. Entire female diabetics should be desexed once they are sufficiently regulated.
Feeding a diabetic cat
Regulation is achieved via a balance of diet, exercise, and insulin. Realizing that therapeutic diets are not always attractive to pets, there are some ideal foods which should at least be offered.
The most up-to-date choice for cats is a low carbohydrate high protein diet. These diets promote weight loss in obese diabetics and are available in both canned and dry formulations such as Science Diet m/d. Talk to your veterinarian to select an appropriate choice for your pet.
Avoid soft-moist diets as sugars are used as preservatives. Avoid breads and sweet treats. If it is not possible to change the pet’s diet, then regulation will just have to be worked out around whatever the pet will eat.