Sudden Collapse in Pets Part I: Common Causes

If your pet suddenly collapses or cannot get up, these are considered “RED” – or true emergencies– on our Fast Track Triage system. We advise you seek immediate veterinary care. Please call ahead of your arrival so the veterinary team knows to expect you!

Your dog is playing in the yard and suddenly collapses. When you rush to him, he doesn’t respond. This can be a terrifying situation for pet parents, especially since the causes of collapse can range from non-life-threatening to extremely life-threatening.

If your pet collapses, it’s important to have them evaluated by your family veterinarian or local animal emergency hospital right away – to narrow down the possible causes and treat underlying issues. We hope you never have this experience, but if you do, we want you to be armed with the necessary knowledge to help your pet!

Since this is a big topic, we’ll first review common causes of why pets collapse in Part I of this blog, and then we’ll discuss what to do if your pet does collapse in Part II.

Common Causes: 

A few of the most common causes for a pet to collapse include the following medical concerns:

• Cardiovascular concerns 

  • When the heart is not pumping effectively or efficiently enough to maintain adequate blood pressure and delivery of important molecules (such as oxygen) and nutrients (such as sugar), our pets’ brains cannot function correctly, and they may lose consciousness. 
  • Causes: 
    • Abnormal heart rhythm (fast, slow, or irregular)
    • Heart valve disease
    • Heart failure
    • Pericardial effusion (fluid around the heart)
    • Blood loss (bleeding in the abdomen or hemoabdomen) 
    • Pulmonary hypertension or systemic hypertension
      • If blood pressure through the lungs or the entire body is too high, then collapse could occur due to the heart’s inability to keep up with the needs of the rest of the body. 
    • Two non-life-threatening causes of collapse are: 
      • Exercise Induced Collapse (EIC) 
        • Typically happens to Labrador dogs under three years old. A pet will suddenly become very weak or unconscious in the middle of exercising. 
      • Vasovagal Collapse (also known as neurocardiogenic collapse)  
        • It occurs when the body essentially overreacts, causing your heart rate and blood pressure to suddenly drop.
        • A similar example in people is when they faint for a few seconds due to fear or pain.

• Respiratory

  • Like the cardiovascular system, the respiratory system also plays an important role in providing enough oxygen to the body.
    • Some causes lead to upper airway obstructions, and it is the airway obstructions that cause the actual collapse. These are also typically preceded by difficulty breathing, which gets progressively worse:
      • Choking
      • Narrow upper airways (common in “smush-faced” dog breeds such as bulldogs and pugs)
      • Tracheal collapse 
    • Other possible causes:
      • Pneumonia
      • Pleural effusion (fluid around the lungs)  
      • Congestive heart failure (fluid in the lungs) 
      • Severe inflammatory airway disease, such as bronchitis 

• Shock

  • Types of shock are typically organized into three categories: 
    • Cardiogenic Shock 
      • The result of severe heart disease and subsequent failure 
    • Distributive Shock
      • Happens when the body is unable to “distribute” nutrients via blood flow/pressure to the rest of the body
      • Examples: Sepsis, heat stroke, and anaphylaxis
    • Hypovolemic Shock 
      • Happens with sudden blood or fluid loss 
      • Example of blood loss: When a tumor on the spleen bleeds and causes blood in the abdomen (hemoabdomen).
      • Example of fluid loss: When a dog or cat becomes dehydrated from severe vomiting or diarrhea.    

Can neurologic issues cause my pet to collapse? 

Most neurologic diseases/disorders do not cause sudden collapse but can look similar.  

Examples include: 

• Seizures 
• Spinal cord injuries leading to paralysis or paresis 
• Toxins such as rodenticides or insecticides 
• Neuromuscular diseases such as tick paralysis, Botulism, Tetanus, and Myasthenia Gravis 

Now that we’ve reviewed the common underlying causes of why a pet may collapse, we encourage you to head over to Part II of this blog to learn what to do if your pet does collapse.  

More Reading: 

• How to Know if Your Pet is Experiencing Respiratory Distress  
• Prevent Your Pets from Overheating 
• My Pet’s Heart Health: 5 Most Common Questions & Answers  
• The 4 Most Common Reasons Pets Visit Our Neurology Service