Hypoglycaemia in dogs: what it means and what to do

Hypoglycaemia is a potentially serious condition where a dog's glucose levels become low. If you have reason to suspect your dog's blood sugar is low, you must see a vet.

Glucose is an essential energy source for your dog and necessary for their body to function normally. Without it, your dog can become very ill. 

Here, we discuss what hypoglycaemia is, its causes, its symptoms, how vets diagnose it and your treatment options.

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What's hypoglycaemia in dogs?

Hypoglycaemia is a drop in blood glucose levels below the "normal range". A normal level is around 3.5-7mmol/L, while low blood glucose in dogs is anything below 3.3 mmol/L.

Glucose is a sugar that provides energy for all of your dog's cells, including the ones in their organs and nervous system.

A dog gets energy by digesting food and breaking it down into small molecules, including glucose. This is then absorbed into the bloodstream and used to give cells energy. So, when this is low, problems happen.

It can have numerous reasons for happening, from too few calories to insulin problems.

Symptoms of hypoglycaemia in dogs

So, what happens when glucose levels are too low and hypoglycaemia occurs?

Mild symptoms (early signs of hypoglycaemia in dogs)

• Confusion

• Incoordination (ataxia)

• Lethargy

• Tremors

• Weakness

Severe symptoms

• Collapse

• Coma

• Disorientation

• Seizures

As you can see, low glucose levels in dogs can have serious repercussions, and you must see your vet if you suspect it.

Recognising symptoms early is a cornerstone of good, preventative pet care. Always let your vet know if you see any hypoglycemic symptoms in your dog.

Causes of hypoglycaemia in dogs

Addison's disease

Addison's disease happens when the adrenal glands are damaged, leading to low levels of cortisol. Cortisol, a dog's stress hormone, is essential in managing blood sugar levels.

Excessive exercise

Too much exercise, especially when combined with too few calories, leads to very low blood sugar in some dogs.

Kidney problems

The same applies to kidneys. Severe kidney disease can cause persistent canine low blood sugar.

Liver problems

Issues with the liver, like cancer and cirrhosis, can cause hypoglycaemia.

Other glycogen issues

Some diseases, like Glycogen storage disease (GSD), can impact your dog's ability to access glycogen, their energy reserves. This leads to persistent low sugar levels in dogs and needs veterinary intervention.

Pancreatic cancer

The pancreas is essential to balancing blood sugar levels through hormone production. Any issues with the organ can cause too much or too little insulin. An insulinoma is an example of a tumour that can lead to hypoglycaemia.

Puppy or toy dog hypoglycaemia

Occurs in very young or small puppies. Their lack of fat, muscle mass and immature liver means they have very little in the way of backup energy stores (glycogen).

Poorly controlled diabetes

Diabetics don’t produce enough of their own insulin so need to be given regular injections. Being given too much insulin can cause their blood sugar to drop too low.

Starvation

Not giving your dog enough calories could cause symptoms to occur.

Sepsis

Sepsis - where the body begins to damage itself in response to serious infection - can affect various organs and hormone production, leading to hypoglycaemia.

Xylitol

Xylitol is an artificial sweetener that is very toxic to dogs, causing a rapid drop in blood sugar, which could be fatal. You must see a vet if you suspect this.

Diagnosis of hypoglycaemia in dogs

Vets diagnose hypoglycaemia with a few tests, and they monitor your dog for obvious symptoms.

Primary tests

Blood glucose test

This is where a vet draws blood to check your dog's glucose levels.

Medical history review

The vet will review your dog's medical history, like their diet, family history and pre-existing conditions.

Observation

Alongside this, your vet will observe your dog for symptoms like lethargy, tremors or weakness.

Secondary tests

Sometimes, it isn't clear what the cause of your dog’s hypoglycaemia is. If so, your vet may then order further tests like:

Blood chemistry profile test

This test looks into your dog's blood to see if their liver and kidneys are working properly.

Complete blood count (CBC)

A CBC checks for anaemia and changes in white blood cell levels that may explain the hypoglycaemia.

Imaging, like x-rays

A vet will order this if they suspect issues like tumours or liver problems.

More specific blood tests

Things like adrenal gland problems can impact your dog’s ability to control their blood sugar. These need to be analysed in more specific blood tests.

Urine analysis

This evaluates kidney function and urinary tract infections.

Treatment of hypoglycaemia in dogs

Most dogs with moderately reduced blood sugar levels will feel okay again after having some food. 

If you suspect your dog is suffering from a severe hypoglycemic episode follow these steps

1. Make sure your pet is somewhere safe if they are collapsed or having a seizure.

2. Administer some glucose orally to try and raise their blood sugar. If they are conscious and alert, you could offer some cooked pasta with some honey or corn syrup, or try offering them some of their usual pet food. If your dog collapses, you should rub some honey or corn syrup on their gums. If you don’t have either of these try some sugar dissolved in a small amount of water.  

3. Take your dog to a vet straight away for further treatment.

What will my vet do?

Your vet will provide glucose or dextrose intravenously if required. Depending on your pet’s condition, they may also need to stay on a drip, where they can be monitored closely. If the cause of your dog's hypoglycaemia is unclear, your vet could need to run some of the tests we have already discussed.

Ongoing treatment  

Ongoing treatment depends on your pet’s diagnosis. If your dog recovers from xylitol poisoning or exercise-induced hypoglycaemia then no further medication is required. 

If your dog has issues with the control of their diabetes then your vet will suggest insulin dose changes. A tumour-related condition like insulinoma could require surgery to resolve. Sadly, glycogen storage disease, advanced kidney disease, and liver failure carry poor long-term prognosis. 

Prevention of hypoglycaemia in dogs

It's not just about treating canine hypoglycaemia; it's about trying to prevent it and keeping on top of symptoms for the long term.

Avoid xylitol

Xylitol is an artificial sweetener that is extremely toxic to dogs. You need to see the vet if you suspect your dog has eaten some.

You can find xylitol in things like sugar-free peanut butter, chewing gum and human medications. Make sure any foods that contain xylitol are placed significantly out of reach and take care when using them.

Close monitoring

Paying close attention to your dog, particularly if they have a condition like diabetes, can help you keep on top of symptoms.

Proper exercise

Exercising your dog is a good thing, but it needs to be the right amount. Exercising your dog too little can cause issues like obesity or poor mental health, but exercising too much is just as bad.

Over-exercising, alongside inappropriate nutrition, can cause hypoglycaemia and glycogen issues.

Regular feeding and good nutrition

Malnutrition is a major cause of hypoglycaemia, so make sure your dog is being fed at regular intervals.

You should know how to feed your dog the right amount and with good quality food. Some dogs may require small meals fed frequently throughout the day, especially young puppies or toy breeds with little energy reserves. If you need help, your vet can point you in the right direction and advise.

Regular vet visits

Sometimes, you don't notice symptoms because they're so subtle. Or, sometimes, your dog could be in the early stages of being unwell but aren't showing any signs yet.

That's why regular vet visits are so important - they can spot things early, which always makes treatment for things like hypoglycaemia easier.

When to see a veterinarian

You must see a vet if your dog shows any signs of hypoglycaemia. It's a serious condition, and you should have a plan in place for emergencies if your dog is at risk.

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