How to spot hypoglycaemia symptoms in cats

Petplan veterinary expert Brian Faulkner explains what hypoglycaemia is, which cats are likely to be affected, and the warning signs to look out for.

Hypoglycaemia is the medical term for low blood sugar. Glucose, or blood sugar, is the main source of energy that keeps your cat’s body functioning correctly.

If the levels of glucose in a cat’s blood drop too low, their energy will start to decrease. If left untreated, this condition can become a medical emergency. Find out what can cause hypoglycaemia, how to spot the signs, and what the treatment options are.

How do cats become hypoglycaemic?

Hypoglycaemia in cats isn’t a disease in itself, but is caused by an underlying health condition. Certain cats are at a higher risk of developing hypoglycaemia.

Cats with diabetes

One of the most common ways for cats to become hypoglycaemic is if they have diabetes. This condition is caused either by your cat’s pancreas not producing enough insulin, or by their body not responding to the insulin it does produce. Most cats with diabetes receive regular insulin injections to help control their blood sugar levels.   

Hypoglycaemia isn’t caused by diabetes itself, but by the injections of insulin. If your cat’s insulin dose is too high, or not enough time passes between injections, the excess insulin can cause your cat’s blood sugar to drop too low.


Young kittens can’t yet regulate their blood sugar levels efficiently.  Stress factors, such as being too cold, poor nutrition, and parasitic worms, can all trigger hypoglycaemia in kittens, particularly those under 12 weeks.

Other conditions  

If your cat isn’t eating enough but exercising excessively, this can cause hypoglycaemia. It is important to feed your cat enough – even more so if they are pregnant – to avoid hypoglycaemia. Some other illnesses, including liver disease and bacterial infections, can also lead to hypoglycaemia.

Hypoglycaemia symptoms in cats

Every cat is different, but if your cat’s blood sugar starts to drop, you may notice they start to develop one or more of the symptoms below: 

1. Changes to eating habits

Watch out for any signs your cat is eating more, or less, than usual. Hypoglycaemia can create food cravings in some cats, while others may eat far less if they’re feeling weak or dizzy.

2. Weakness and lethargy

Low blood sugar means there’s less fuel available to help power your cat’s muscles. This can sometimes lead to weakness, lethargy and a general reluctance to move.

3. Bumbling behaviour

Hypoglycaemia can cause blurred vision, disorientation and confusion. These issues can impact your cat’s ability to carry out normal tasks like using their cat flap or jumping onto furniture.

4. Jerking or twitching

If left untreated, a hypoglycaemic episode can lead to trembling, collapse or even seizures. These often occur just before a cat loses consciousness, a situation that should be treated as an emergency.

Treating hypoglycaemia in cats

If your cat is diabetic, or at risk of developing low blood sugar for another reason, be sure to watch out for the symptoms above. They can be subtle during the early stages of hypoglycaemia and some cats may not show any obvious signs, but just become slightly quieter than normal.

Contact your vet as soon as you notice any signs of hypoglycaemia. They will advise you on how to treat your cat at home, or ask you to take them in for tests and treatment.

Often, mild cases of hypoglycaemia can be resolved by giving your cat a small amount of sugar. You can rub honey or corn syrup into their gums or under their tongue. Then offer food every hour until your cat’s glucose levels are back to normal. Keeping your cat calm can also help, as if they’re overstimulated or stressed, this can create an increased demand for energy that can make things worse. In severe cases, intravenous dextrose may be administered at your vet practice to help increase blood sugar levels. Even if things seem to normalise after home treatment, it is always sensible to take your cat to the vet soon afterwards for a check-up.

Injecting insulin safely

If your cat is diabetic, your vet may recommend that you start measuring their blood sugar levels using a glucometer before giving an insulin injection. Doing this can help make sure you’re giving the correct dose and reduce the likelihood of hypoglycaemia.

If multiple members of your family are trained to give your cat insulin, make sure everyone communicates clearly about when an injection was last given, so the chances of giving a double dose are reduced. If your cat’s weight or eating habits change, you may need to adjust their insulin dosage to prevent hypoglycaemia or its opposite, hyperglycaemia, which is when blood sugar levels are too high. 

Hypoglycaemia in cats can be caused by a range of health conditions, with diabetes being one of the most common. Your vet can provide tips or training to help you cope with this condition.

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