Causes Of Collapse In Dogs

Updated September 3, 2021

Emergency facts (details below):

When a dog suddenly falls over or cannot use their back legs, it is usually an emergency. You should travel to a vet.

On the way, take a video if you can. Here are some things to look for:

  1. Is there muscle movement? This is common in seizures or poisonings.
  2. Is the dog unconscious? Look for a lack of response and passing urine or faeces.
  3. Are the eyes moving? Vestibular disease causes nystagmus or eye flicking.
  4. Is the heart rhythm normal? Place your hand on the chest and try to feel it.
  5. How long does it last? Fainting and airway issues usually only last for seconds.
  6. Is recovery quick? After seizures, dogs commonly appear incoordinated for some time.
  7. What was the dog doing beforehand? Cardiac, respiratory and thermal problems are more common after exercise.

Cardiac arrest is an extremely uncommon cause, and therefore it is not recommended to try CPR. You will see that most causes either recover by themselves or require treatment that only a vet can give.

Now let’s dive deeper into each of these causes…

Cardiac Causes Of Collapse

Collapse would make people immediately think of the heart, and they’d mostly be right. Any heart disease can cause collapse due to fainting or syncope, which is essentially ‘blacking out’ from a lack of oxygen in the brain.

Cardiac collapse most often occurs after excitement or exercise, and might only last a few seconds each time. In our clinic, the following heart diseases are more likely to cause collapse:

  • rhythm disturbances (arrhythmias such as heart block, Boxer cardiomyopathy)
  • late stage mitral insufficiency
  • pericardial effusion

Many causes are treatable. Read more about these in our page on heart diseases.

Shock & Bleeding

The most common cause of acute shock is bee sting in dogs.

Low blood volume or anaemia can cause collapse that looks just like cardiac disease. The best clue is very pale, almost white gums. Perhaps the one we see most is rat bait poisoning, which causes internal bleeding. Two autoimmune diseases which have similar signs are platelet deficiency and haemolytic anaemia.

Another common cause of sudden collapse due to internal bleeding is a tumour of the spleen called haemangioma or haemangiosarcoma. It is seen mostly in older large breed dogs. Spleen removal can be curative but an ultrasound exam is best done first to look for tumour spread.

Rapid fluid shifts in the body cause shock, of which by far the most common cause is any severe and sudden gastroenteritis. In these, body fluids go from the blood vessels into the gut faster than they can be replaced and the circulation collapses. The treatment is of course prompt restoration of the fluids via a drip.

Respiratory Causes Of Collapse

Any problems of the airways or lungs can cause collapse due to hypoxia. Here are some of the ones we see more often.

Brachycephalic Obstructive Airway Syndrome or BOAS occurs in dogs with short faces, like Bulldogs and Pugs. When there’s a need to breathe quickly, the soft palate that lies over the larynx in some dogs will block enough airflow to cause collapse. This can be complicated by a narrow trachea (windpipe) and small nasal openings.

If a brachycephalic breed has noisy breathing even when at rest, or gets tired easily, they almost always benefit from airway surgery. Acting proactively can save a life.

Collapsing trachea is a common cause of a honking or harsh dry cough in older small breeds. When they get hot or excited, the airflow through the flattened windpipe sometimes can’t keep up with demand and the dog might collapse for a few seconds. Treatment involves various medication combinations, weight loss, avoiding excitement, and surgery as a last resort.

dog tracheal collapse xray
Tracheal collapse

Laryngeal paralysis is a similar problem mainly seen from middle age in medium and large breeds. Instead of a cough, they have harsh, raspy breathing that gets louder with exercise or temperature. Collapse most commonly occurs in warm conditions, but can be prevented by timely surgery.

Pulmonary hypertension is a rarer disease of the lungs secondary to many problems, such as heartworm, birth defects in the heart and a specific disease of West Highland White terriers. It can also happen when blood clots are formed associated with immune-mediated haemolytic anaemia, protein-losing diseases and Cushing’s disease.

Neurological Causes Of Collapse

Any poison that affects the nervous system can cause a dog to collapse. In Australia, the most common are:

Three neurotoxins found in Australian animals also deserve special mention: tick paralysis, cane toads, and snake bite, which often causes immediate collapse followed by a short-lived recovery. Other toxins are ethyl glycol in engine coolant, bromethalin in rat baits outside Australia, insecticides and herbicides.

What about deliberate dog baiting? It’s rare, but does happen. Read more at the link.

Any injury or trauma to the brain or spinal cord can cause collapse. The best example of this is intervertebral disc disease, which is especially common in dogs like Dachshunds.

Seizures can also be a cause of collapse. Usually they’re easy to identify by paddling leg movements, jaw champing and salivation, but sometimes these aren’t obvious. That’s especially true for partial seizures where the dog remains conscious throughout.

A portosystemic shunt is an abnormal blood vessel that sends unprocessed blood from the gut directly to the brain, bypassing the liver. It can cause collapse especially not long after a meal. A shunt would be high on the list in a young adult of a susceptible breed such as the Maltese.

Low blood sugar also causes neurological signs. Collapse in a diabetic dog is most often due to a high insulin dose suppressing blood glucose levels, but we also see it with insulinoma, Addison’s disease and very young puppies not getting adequate nutrition.

The last item on the nervous system list is vestibular disease. This refers to any disorder that affects the balance organs in the inner ear and brain. These dogs have a head tilt, fast flicking in the eyes, and usually can’t stand up. The most common is Idiopathic Vestibular Syndrome, but you can read all the common causes of vestibular disease here.

Musculoskeletal Causes

As a young vet, I didn’t believe it when I first saw simple arthritis cause a dog to collapse. Why would a long-term disease known for slow worsening lead to sudden collapse? Now I understand that these dogs have been putting up with pain until they couldn’t any longer.

We see this mainly in larger breeds, and especially German Shepherds. Often they will be howling or crying and brought in on a stretcher. Good intravenous drugs (especially cortisone) can do wonders to get them up again but they really need long-term pain control to keep them going.

Of course, we should view these dogs as our own failure. To do it right would be to identify and treat their pain before it gets too much.

Exercise-Induced Collapse

Let’s finish up with two unusual conditions. Hyperthermia or heat stroke won’t often cause outright collapse, but it can cause an unsteady gait and vacant expression. The clue is that it should happen after prolonged exercise or excitement especially in warm weather.

We see heat stroke most in dogs obsessed by ball-chasing, or overly excitable dogs, but there may also be a genetic influence in some breeds such as Spaniels. For many dogs, the solution is to realise that dogs don’t know when to stop and that you need to regulate their exercise and keep them calm.

Exercise induced collapse is a genetic fault found in Labradors, Border Collies and others. It causes muscle weakness, incoordination and life-threatening collapse after intense exercise. The genetic mutation in Labradors is now understood and screening by many breeders should reduce the incidence.

This list is by no means complete but all the common reasons for collapse should be found here. Diagnosis will require your vet using the history you give them, taking a physical exam and choosing the right tests to confirm their suspicion. Good luck.

Have something to add? Comments (if open) will appear within 24 hours.
By Andrew Spanner BVSc(Hons) MVetStud, a vet in Adelaide, Australia. Meet his team here. The information provided here is not intended to be used as a substitute for going to the vet. If your pet is unwell, please seek veterinary attention.

24 Replies to “Causes Of Collapse In Dogs”

  1. My sweet girl Chloe just fell slowly collapsed and defected & peed herself tonight when we were done with our walk about to go inside and just lay there on her belly with her legs sprawled out to her sides. Her eyes were open but she seemed out of it and I was terrified she was dying. I picked her up and she was like dead weight very limp and brought her inside to clean her up and her gums were pale and she had slobber also on her mouth. I don’t know why this happened but I gave her water with a syringe and let her rest and within an hour she was standing and drinking on her own. She is on medication for arthritis cuz she’s 14.5 years old but I don’t know what’s causing this to happen to her because this is her second time this happened. I woke up one night a few weeks ago to my other dog grunting and found Chloe on her belly same situation defected and peed and couldn’t stand up. I don’t know what is happening because she just bounces back to pretty normal.

    1. Hi Jennifer. The most likely explanation will be a heart problem, since this is exactly what it looks like, and it often occurs around the time of excitement or exercise. Only a checkup with a vet can answer the question properly, but there is good treatment if you get the diagnosis.

    2. My 17 year old dog does the same and originally when I took him to the vet they said it was pancreatitis. So I really limit his meals one small meal in the morning, one at night with his meds and a carrot fo me a treat during the day. The only time this happens now is if he gets into a bag or a plate of food someone has left around the house but he’s a beagle

  2. I hav A 12-year-old Maltese that has been diagnosed with congestive heart failure started out as a murmur he’s fainted now on me like eight or nine times and it’s usually when he chases a cat or a duck he collapses in a pile With his eyes open. he’s still breathing but can not move . Finally his tail will start to move because I sitting there talking to him. Hoping he comes out of this state. There was one time where his front leg was stiff And it always takes awhile for him to recover enough to get up.
    He’s on medicine and I have him on supplements .
    I really wish these things could be fixed. I can not prepare myself for what’s coming. I just hope he doesn’t struggle ar suffer in any way . I don’t want to have to make that call to put him down. That will tear me apart.
    Whenever he drinks water he will cough and then gag big. When he wakes up and stretches he does the same thing and when I have been gone and come home he’ll get excited and cough , shake his head and gag. It’s getting worse daily I feel like . He has a vet appt Friday. I hope we make it til Friday . ER s are so expensive Along with his meds.
    I must say ; reading all these posts o diffrent subjects really hit home . So many people are having these episodes and don’t understand or know what to do next . I’m glad I found this page . Maybe I can understand and do something to help my next pet. Because I v learned a lot about medicine , the food we feed, the vaccines they wa nt to give so much of . That’s wrong.
    If only they could live forever.

  3. I have a 4 year old frenchie that has lost function by in both rear legs for about 90 seconds. The legs are super stiff and will relax once the episode passes. Would love any insight!

    1. Hi Diana. This one will require a check up and even then it will be hard to work out. Take in a video of the episode and try to work out whether it happened after exercise or at rest.

  4. hi so my dog has been collapsing but it’s only when he gets a little excited. My dog is about 5 years old i would say and he just now has this problem this day and he’s never had a problem with this. It’s already happened twice today and it’s a little scary. So i was wondering if you any things that u would recommend me to do.

    1. Hi star. You should find answers within the article, but if collapse occurs during excitement, you need to think of problems with oxygen delivery, such as involving the circulation, lungs or heart.

  5. I have a 10 year old boxer that recently started snoring a lot louder. She has now started to made a sound like it hard to breathe in her sleep for a few seconds and then collapses. During this time she pees herself. This lasts for around a min the she gets up and is fine. I’m not sure if she is fainting or have a seizure ? I took her to the vet where they did a full blood workup, urinalysis and chest and spine X-ray. They did not find anything wrong. They prescribed her seizure medicine which I have not yet started. I’m afraid it may be her heart and have been trying to get into a cardiologist. Please any advise or suggestions would help! Should I try the seizures medication? I have a video. If you can possibly view it.

    1. Hi Ashley. You should look up the common cardiac arrhythmia of boxers, as this is probably the most common reason we see for collapse in the breed.

  6. My 15 year-old cockapoo was diagnosed two years ago with a mitral valve murmur and has been on pimobendan ever since. his disease seems to be stable or progressing very slowly but in the last 10 months he has started to have episodes of passing out. some have occurred when he has gotten too excited. but the majority have occurred in the middle of the night when he has been sleeping. He starts to cough (or sound like he is going to vomit) he starts to shake rather violently and then lets out a high pitched sound and passes out (sometimes he passes urine sometimes not) he is out for 30 seconds to a minute and then seems fine. Is this related to his heart? his medication?? or some other cause?

    1. Hi Carolyn. That sounds like a worsening of the heart disease. I’m unsure if other medications would help, but they are definitely worth a try in addition to the pimobendan.

  7. Okay. I have a rescue puppy that just wondered up out of no where. Had him for roughly 2 weeks and he has these little episodes where he loses his balance with his head tilted and he runs around jumping and yelping at my husband and myself like he’s crying for help. When these happen they could last hours or minutes, he gets very weak, he can’t hardly stand up and if he does he’s very off balance and almost seems like he’s going to faint. He had no wounds tha we could see when he was rescued. He has no been to the vet because we are not rich by any means but I can’t just let this little guy suffer. Any ideas on what it could he amdhow to help him are extremely appreciated. Thank you! We have no idea what type of dog or how old, he’s a small breed almost like a jack Russell mix with chaihawa maybe. He is peeing and pooping normal and his appetite has no changed even during these episodes.

    1. Hi Hunter. The only way to prevent the suffering is to go to a vet as soon as possible. It sounds most likely to be a middle or inner ear infection.

  8. Hi!
    My 14 year, then 13, old girl collapsed for the first time in August last year. We were playing on the beach, not long at all and not so warm weather, snd she just collapsed On her side. She did not move or shake , just laying down with open eyes. I lifted her immediately and dhe was very heavy and weak in her legs. After maybe a minute or two she was back to her normal self again, continuing running and playing. It was so scary to experience. The vet checked her the day after and couldn’t find anything wrong.
    The same thing happened a couple months later again, during winter and colder weather. We were playing fetch and when she was running back she suddenly slowed down and then collapsed again. Everyrhing the same as first time, helped her up and back on her legs soon and nothing strange after…behaving otherwise completely normal.

    The third time it happened was a couple of months later once again. However this time she was weak for a couple of minutes longer and after vomited.
    This time we went to the vet and they examined her again, because after she also had fever, and they diagnoaws rhat she had developed lymphoma stage 5 (in the spleen and in the blood). She stopped eating too the day after.

    Now, could it really be the same reason she collapsed in August and December and then get diagnosed with lymphoma because bad bloodwork first time in march? Or is just this collapse and the last one same symptoms of different problems? I have read somewhere thst brain tumors also can cause collapses, but can one have a braintumor for more then 6 months and live normally otherwise…? They never found anything wrong with her heart, other then slight murmur sometime

    I am so conflicted and confused. Unfortunately my dog deteriorated very quickly from lymphoma snd is not with us anymore, but the questions about all these collapses are still there…

    1. Hi Marko. In my opinion, the collapse and the lymphoma are separate problems. It’s very unlikely that lymphoma could be present for so long without showing more signs.

      1. Hi,
        I also think they are two separate problems. My beloved dog died todas with a collapsed tranchea. He was also treating câncer.

  9. My dog collapsed this morning and died. He was 13 and had a heart murmur, liver disease, chronic arthritis and a collapsed trachea.

  10. My westie has been having class 4 laser treatment for WLD or APF could this cause any adverse effect culminating in legs collapsing. The vet mentioned arthritis and a lack of blood supply to the legs. My dog was 15 and was taking medication for her joints

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