Dog or cat that has collapsed

Recognise the signs

• Sudden inability to stand or hold weight
• Lying on side, possibly unresponsive
• Open-mouth breathing or no breathing
• Pale, blue, or muddy gums
• Loss of bladder or bowel control
• Stiff, paddling legs (suggests seizure)
• Cats with sudden hindlimb paralysis and crying out — saddle thrombus, true emergency

First aid steps

1. Phone the emergency vet — speakerphone while attending to the pet.
2. Check airway — gently extend the head and neck, clear any vomit or saliva from the mouth with a finger or cloth.
3. Check breathing — watch chest movement for 10 seconds.
4. Check pulse — feel high on the inner thigh (femoral) for both dogs and cats.
5. If breathing and conscious, lay on right side with head slightly extended, cover with a blanket.
6. If not breathing and no pulse, start CPR (see pet-cpr) while travelling to the vet.

While transporting to the vet

• Continue monitoring breathing and pulse.
• Keep warm but not overheated.
• If suspected heat stroke, cool with damp towels and AC instead.
• Phone ahead so emergency drugs and oxygen are ready.

Common causes

• Heart disease or arrhythmia
• Internal bleeding (splenic mass rupture, trauma)
• Severe anaemia
• Heat stroke
• Hypoglycaemia (low blood sugar — small breeds, diabetics, puppies)
• Addisonian crisis
• Bloat / GDV (dogs)
• Saddle thrombus (cats)
• Seizure recovery (post-ictal collapse)
• Severe allergic reaction (anaphylaxis)
• Poisoning

What the vet will need to know

• Time of collapse
• What the pet was doing immediately before
• Duration of collapse and recovery
• Any seizure activity, vomiting, or distress
• Known medical conditions and current medications
• Last meal — relevant for diabetics and small breeds at risk of low blood sugar
• Any known toxin access

Aftercare

• Diagnostics typically include bloods, ECG, ultrasound, and X-rays.
• Treatment depends on cause — fluids, transfusion, oxygen, specific drugs.
• Cardiac collapse may need long-term medication.
• Diabetic emergencies need home glucose monitoring discussion.

Prevention

• Annual checks with bloods and where indicated, an ECG for older or breed-prone pets.
• Treat known conditions (heart disease, diabetes, Addison's) consistently — never stop medication suddenly.
• Avoid heat stroke triggers in summer.
• Keep emergency vet number and route saved on phone.

Breed-specific notes

• Cardiac collapse: Cavalier King Charles Spaniel, Doberman, Boxer, large/giant breeds.
• Splenic mass rupture: large/giant breed older dogs (German Shepherd, Golden Retriever, Labrador).
• Saddle thrombus: cats with underlying cardiomyopathy, especially Maine Coon and Ragdoll.

Frequently asked questions

Related topics

• How to do CPR on a dog or cat
• Pale or white gums in dogs and cats
• Dog with bloat or suspected GDV (twisted stomach)
• Cat with sudden hindleg paralysis (saddle thrombus)