When Heartworms Become a Pet Emergency: Recognizing the Signs

Heartworm disease is often a slow-developing condition, but in advanced stages, it can turn into a true emergency. At Small Animal Emergency Hospital of Westfield, we know how quickly a seemingly manageable issue can escalate into a life-threatening situation. Understanding the signs of heartworm complications—and when to act fast—can be the difference between life and death for your pet. During National Heartworm Awareness Month, we want to help pet owners recognize urgent symptoms of heartworm disease and know when to seek emergency care.

What is Heartworm Disease?

Heartworms are parasitic worms that live in the heart, lungs, and blood vessels of affected pets. Heartworm disease primarily affects dogs, though cats can be infected, too. The disease is spread by mosquitoes and can go unnoticed for a long time. However, once symptoms appear, especially in unprotected pets, the situation can deteriorate quickly.

In the early stages, heartworm disease may show no symptoms at all or cause only mild coughing or fatigue. But as the worms multiply and block major blood vessels, it puts extreme strain on your pet’s heart and lungs. Left untreated, the condition can become life-threatening.

Emergency Signs of Heartworm in Pets

When these symptoms appear, time is critical. Emergency care for heartworm may include oxygen therapy, IV fluids, or medications to stabilize heart and lung function. The earlier the intervention, the better the outcome. If your pet displays any of the following heartworm symptoms, it's time to seek urgent or emergency veterinary care.

• Sudden Collapse or Fainting: This may indicate cardiovascular collapse caused by a large number of worms obstructing blood flow.
• Labored Breathing or Wheezing: Difficulty breathing is a sign that the lungs are under severe stress, often from inflammation, fluid buildup, or embolism.
• Pale Gums or Blue-Tinted Tongue: These are signs of poor oxygenation and circulation—an emergency that could lead to shock or organ failure if not treated quickly.
• Swollen Abdomen: A distended belly can signal congestive heart failure caused by severe worm load, resulting in fluid buildup.
• Sudden Lethargy or Disinterest in Normal Activities: A normally active dog that suddenly becomes weak or unresponsive may be experiencing heart failure or embolism.

How to Prevent Heartworm Emergencies

The best way to avoid a heartworm emergency is to prevent heartworm disease in the first place. Year-round heartworm prevention, annual testing, and prompt treatment of early signs can drastically reduce the risk of complications.

For pets already undergoing heartworm treatment, it’s important to:

• Strictly limit physical activity
• Follow your vet’s instructions closely
• Monitor for adverse reactions to medication

If your pet is being treated and suddenly begins to show any of the emergency signs listed above, bring them to an emergency vet clinic immediately.

Save Your Pet from a Heartworm Emergency with Small Animal Emergency Hospital of Westfield

When not caught early, heartworm disease can become a critical emergency, and knowing what to look for can save your pet’s life. Small Animal Emergency Hospital of Westfield is here to handle the urgent needs of pets in crisis. Don’t wait and wonder—if your pet is struggling to breathe, collapses, or shows signs of distress, come see us right away. We serve Westfield, Carmel, Noblesville, and nearby areas with urgent and emergency care for cats and dogs. If your pet is showing sudden or severe signs of illness related to heartworms or any other condition, call us for assistance. We’re ready to provide life-saving care when every second counts.