Normal vs Diabetic Blood Sugar Levels
Blood sugar is the energy source that keeps everything in a cat’s body working normally. Any carbohydrate that a cat eats is broken down in the gastro-intestinal tract and is absorbed into the blood as sugar. Insulin plays a vital role in managing blood sugar as it helps sugar move from the blood into the cells of the body. Insulin unlocks the door for the blood sugar to move into cells, and without that open door, sugar builds up in the blood.
Normal blood sugar is in the range of 80-120 mg/dL for cats.
Diabetic blood sugar levels are above this range and typically higher than 200 mg/dL.
Monitoring Diabetic Cats
If your cat has diabetes, there are a few things that your veterinarian may ask you to monitor:
- Signs of diabetes
- Urine sugar
- Blood sugar
Signs of Diabetes
When your diabetic cat starts treatment, you’ll be asked to keep an eye on their appetite, and how much they are drinking and urinating. Keeping a diary is a simple way to notice slight changes over time. This will help you and your veterinarian know how well-managed your cat’s diabetes is.
Urine Sugar
Your veterinarian may ask you to check their urine for glucose (done with a simple dipstick, which is a test strip applied to the litter and may show presence of glucose).
Blood Sugar
Regular blood sugar monitoring is important when cats with feline diabetes are being treated with insulin. This can be done in a number of ways—sometimes a veterinarian will ask you to check your cat’s blood sugar just before they are given their dose of insulin (not to worry, they will show you how!), or the vet may take a blood sample to measure fructosamine. Fructosamine shows how high the blood sugar has been on average over the last two weeks.
Some veterinarians use continuous glucose monitors (eg, FreeStyle Libre) that take readings several times a day over several days.
Sometimes your veterinarian may need to see a blood glucose curve. Lots of pet owners worry about getting a blood sample from their cat, but with a little practice, it’s straightforward.
Understanding Blood Sugar Curves
A blood sugar curve tells the veterinarian how quickly the blood sugar goes down after treatment and when it starts to go back up. It gives them the information they need to help them ensure that a diabetic cat is getting just the right amount of insulin.
A blood glucose curve can be done in the clinic or at home. Unfortunately, stress affects blood sugar levels, and cats often feel stressed in the clinic environment, so blood sugar curves done in the clinic can be challenging to interpret. Running a blood sugar curve at home is therefore often preferred.
Blood Sugar Testing
Getting a blood sample at home is easier than you might think. Only a tiny drop of blood is needed, and you simply collect this into a test strip and then use a use a hand-held device called a glucometer to check the sugar levels. Your veterinarian will show you how to use a small lancet on the edge of your cat’s ear or paw pad to get just enough blood. Most cats tolerate this well, and most owners find it easy after doing it a few times.
To run a blood sugar curve, your veterinarian will ask you to take blood samples throughout the day (normally every 2-4 hours for up to 12 hours). The first sample is usually taken before the morning insulin and food. Your veterinarian will then create and evaluate the results on a chart (the “curve”) and decide whether your cat needs any more or less insulin to control their diabetes.
You should never alter your cat’s insulin treatment without checking with your veterinarian first.
Because blood sugar comes from what a cat eats, it’s important to feed an appropriate diet. The ideal food for a diabetic cat is low in carbohydrates and high in protein, to help avoid large and sudden spikes in blood sugar after eating.1 Many commercial cat foods are high in carbohydrates, so your veterinarian will often recommend a food that is specially formulated for diabetic cats.
To help keep a diabetic cat stable, they should have a very consistent feeding schedule, with the same amount and type of food given at the same time each day. Your veterinarian will help you create a feeding schedule that best fits your cat and your lifestyle.
Obesity is an important contributing factor to feline diabetes; therefore your veterinarian will give you tips on how to maintain your cat’s ideal weight so that their diabetes can be managed better.
Signs of Hyperglycemia (High Blood Sugar)
Hyperglycemia in cats occurs when the blood sugar levels are too high. This can happen when a diabetic cat hasn’t yet been diagnosed or when they aren’t getting enough insulin.
Signs to look for include:
- Excessive thirst
- Excessive urination
- Increased appetite
- Weight loss
If you notice any of these signs, contact your veterinarian so that they can assess your cat’s treatment.
Signs of Hypoglycemia (Low Blood Sugar)
Hypoglycemia in cats occurs when the blood sugar becomes too low and there is not enough energy for the cells to function normally, especially in the brain. It can happen after an insulin dose is given if either the dose is higher than the cat needs or they don’t eat enough food.
Signs to look for include:
- Lethargy
- Being wobbly on their feet
- Sometimes seizures can occur
Hypoglycemia Is Serious and Needs Urgent Treatment
If your diabetic cat seems lethargic or wobbly, then you should rub a sweet liquid on their gums, such as corn syrup, molasses, or honey. This will help increase the blood sugar quickly. This fix is only temporary; therefore, you should take your cat to your veterinarian or an emergency clinic straight away for follow-up monitoring and treatment. If you have a veterinary glucose monitor at home, get a quick reading after giving them a sweet liquid and call your veterinarian for further advice.
Feline diabetes can be managed very successfully, giving diabetic cats an excellent quality of life and helping them live many happy years with their owner. To ensure this success, regular checkups with the veterinarian are important to monitor and adjust the treatment plan as needed. Feline diabetes complications tend to occur where cats are either not diagnosed or treated, or where their diabetes isn’t well controlled. The potential long-term effects of feline diabetes are best avoided by early diagnosis, regular monitoring, and consistent treatment.
Common Long-Term Side Effects of Feline Diabetes
Nerve Damage
Uncontrolled high blood sugar can be toxic to certain cells in the body. The cells in the nervous system are particularly sensitive to this. Over time the nerves in the back legs can be affected, leading to something called a “plantigrade” stance (when a cat stands with its weight on its heels or ankles, instead of its paws).
Kidney Damage
Just like the nervous system, the kidneys are sensitive to damage from high blood sugar levels, contributing to chronic kidney disease.
Blindness
Just like diabetes in people, persistently high blood sugar can cause cataracts in diabetic cats’ eyes, leading to blindness (not common in cats).
Urinary Tract Infections
The excess sugar in the urine can predispose cats to developing urinary tract infections, which may require antibiotics to treat the infection.
Diabetic Ketoacidosis (DKA)
When the body can’t use sugar as a fuel, it turns to fat and proteins instead. The breakdown of excess fats produces ketones that cause the blood to become acidic and results in electrolyte imbalances in the blood.
Signs of DKA include:
- Vomiting
- Lethargy or weakness
- Reduced appetite
- Dehydration
- Sweet smell to breath
- Breathing faster
- Drinking more
- Urinating more
Key Takeaways
Diabetes can be successfully managed with a little care and knowledge.
Early diagnosis and regular monitoring are key to avoid complications.
Some signs of possible diabetes to watch out for include drinking and urinating more, eating more, and weight loss.
Blood glucose curves help with diabetic monitoring and can be easily run at home.
Recognizing the signs of hypoglycemia quickly (lethargy, wobbly on legs, seizures), giving sugar, and contacting your veterinarian without delay will help to keep your diabetic cat safe.
