Low blood sugar in dogs: signs, what to do, and causes

Low blood sugar in a dog: what to do right now

If you think your dog's blood sugar is low, treat it as an emergency. Don't stop to search, take a reading or wait for a reply to a message. Do these in order:

First, if he's awake and can swallow, rub something sugary your vet has approved, such as honey or syrup, onto his gums and the inside of his cheek. Keep your fingers clear of his teeth. How much sugar to give is your vet's call, not mine.

Then call your vet or an emergency clinic now, or have someone call while you stay with him. Tell them he's diabetic, the name of his insulin, and when he last ate and last had insulin.

Never pour liquid into his mouth, and don't try to feed a dog who can't swallow properly. It can go into his lungs. Once you see signs, don't take him for a walk to see if he improves, because exercise uses up sugar.

If he's awake, steady on his feet and wants his food, you can offer him a little of his usual food while you watch him. Call your vet anyway and ask what to do next.

If he has collapsed, won't respond or is having a seizure, go to a vet now and ring ahead on the way. The emergency page has the same steps in one place, ready for your phone.

Even if he perks up quickly, follow what your vet tells you. A low can come back while the insulin is still working.

My dog's sugar runs high. Why would he go low?

It's the diabetes that makes the sugar high. A low comes from the treatment.

Insulin moves sugar out of the blood and into the body. On a normal day his dose is matched to his meals and his usual activity. If, on one day, there's more insulin working than his food and activity can match, his sugar can fall too far. That's why any dog on insulin can have a low, however high his readings usually are.

A low can come on fast, so it's worth knowing the signs before you ever need them. If you've already been through one and can't stop worrying, living with fear after a low is for you.

Signs of low blood sugar in dogs, from mild to severe

Early or mild signs are easy to miss. He seems tired or quieter than usual, restless, unusually hungry, a bit shaky or trembling, or just not himself. In an older dog who sleeps a lot, a mild low can look exactly like a nap.

As it gets worse you may see wobbling or walking as if he's drunk, weak back legs, twitching, confusion or staring, vomiting, trouble seeing or bumping into things, and finally a seizure or collapse.

Your dog doesn't need to show all of them. One is enough to call your vet. If you're not sure, call anyway. You know your dog best.

Lows tend to happen when the insulin is working hardest, which is often some hours after the shot rather than straight after it, and after an unusually long walk or a lot of play. Ask your vet when his insulin works hardest, so you know when to watch him most closely. A low can happen at night too. See low blood sugar at night.

After a low: the next insulin dose

Don't give the next insulin shot until you've spoken to your vet. Many vets lower the dose after a low. That's their decision to make.

Never raise the dose yourself, and never give extra insulin to bring down a high reading after a low. If you're not sure a shot went in, or it might have been given twice, don't give another. Call your vet. What to do if the insulin may have been given twice covers this.

Write down what happened while it's fresh: the time, what you saw, when he last ate and had insulin, what you gave and when, and what the vet said. Then ask the clinic for a written plan for lows, in their words, so next time you're not searching in a panic. You can take questions for the vet to that visit.

What usually causes a low in a diabetic dog, and how to prevent it

Most lows in diabetic dogs come back to the same few things.

He ate less, or vomited, after his insulin. Most vets want the meal eaten before the shot for exactly this reason. If he ate only part of it, call your vet before you do anything else. See my diabetic dog ate only part of the meal.

The insulin was given twice. This happens more easily than you'd think when more than one person looks after him. Keep one chart by the insulin that everyone ticks straight after the shot.

Much more exercise than usual. A long walk, a run or an afternoon of play burns sugar. Keep walks a similar length and time each day. How walks work for a diabetic dog has more, and if he's weak or wobbly after a walk, stop and call your vet.

A change in food, treats or routine, an illness, or a different insulin. Talk to your vet before you change any of them, and watch him more closely for the first few days after any change.

His insulin needs drop. Some dogs need less insulin over time, for example as another illness like pancreatitis settles, or rarely in remission. A dose that used to be right can become too much. Repeated mild signs are a reason to ask your vet for a recheck.

What to keep ready for a low

It's much easier to stay calm in a low if you've planned for it on a good day. Ask your vet what sugary thing to keep, how to give it and where to go afterwards, and keep it both in the house and in your walking bag. There's a fuller checklist on what to keep ready in case your dog goes low.

Next to it, keep your vet's number, the nearest late-night clinic's number and the route, and a card with his insulin name, his food and the time of his last shot, ready to read out on the phone. Show everyone who looks after him where it all is.

A high reading after a low

Sometimes a dog's sugar swings high after a low, because the body releases hormones to push it back up. Vets call this a rebound, or the Somogyi effect. It's thought to be less common than people once believed, but it's one reason a single high reading doesn't mean he needs more insulin.

If you see a high reading after a low, or after a day when he seemed off, tell your vet and leave his insulin as it is until they say otherwise. Questions to ask about a rebound helps you prepare for that call.

Low blood sugar in a dog without diabetes

Low blood sugar isn't only a diabetes problem. Very small breeds and young puppies can go low if they miss meals, and hard-working dogs can go low during long days of hunting or running. In older dogs, a tumour of the pancreas called an insulinoma, liver disease, Addison's disease and severe infections can all cause it.

Xylitol, a sweetener in some sugar-free gum, sweets, peanut butters and baked goods, can make a dog's sugar drop sharply. If your dog has eaten anything that contains it, call your vet or an emergency clinic straight away, even if he seems fine.

If your dog isn't diabetic but seems weak, wobbly or confused, or has a seizure, the steps are the same: call your vet now, and go in if he collapses.