Molly,* a chocolate lab, lay in the oxygen cage, laboring to breathe. The night before, we had carried her into our hospital on a stretcher, because she was too weak to walk. Her gums were blue, and she was coughing up blood. Molly had been at our hospital only two weeks before, for the adulticide stage of her heartworm treatment.

Gentle Touch Animal Hospital wants your pet never to experience the life-threatening distress that Molly endured. Read on to learn how this emergency arose, and how to ensure this does not happen to your dog.

How did Molly get heartworms?

When Molly was a little chocolate fur-ball lab puppy, her family started her on heartworm preventive, as our team recommended. But, as the years went by, Molly’s family got busier and busier, and they stopped giving her heartworm medicine. Mosquitoes transmit heartworms to pets, and as you may have experienced, mosquitoes are active much of the year in Denver. One bite from a carrier mosquito, and Molly was infected with heartworms in their microscopic, larval form. Because Molly was not protected by a preventive, the worms migrated through her body over a six-month period and had matured into adult heartworms by the time they reached her heart and pulmonary (i.e., lung) arteries.

What were Molly’s heartworm disease signs?

At first, Molly showed no infection signs, but the heartworms grew, bred, and multiplied into hundreds of thin, string-like worms as long as a foot that traveled to her heart and main pulmonary artery, and she developed a cough. The owners did not notice that Molly was gradually worsening until she had reached stage 2 heartworm disease. They knew Molly was not as active as usual, and fortunately brought her to our hospital. On her physical exam, our team found Molly had pale gums, which indicated decreased oxygenation and anemia, harsh breathing, and weight loss. If Molly had gone undiagnosed, her heartworm disease would have progressed to stage 3 and she would have shown congestive heart failure signs, such as fluid in the abdomen and lungs. Dogs in stage 4 heartworm disease have organ system failure, and often do not survive.

How was Molly’s heartworm disease diagnosed?

Our veterinary team ran a quick, pet-side antigen test that required only a few drops of Molly’s blood, and showed positive for the presence of adult worms in her heart and lungs. A microfilaria test also showed that immature worms were living in her bloodstream. Additional testing—a complete blood count, chemistry panel, and urinalysis—was needed next, to stage her disease. Our team performed digital X-ray and ultrasound in our hospital, so Molly did not experience the added stress of referral to another facility. 

How was Molly’s heartworm infection treated?

Canine heartworm treatment is a months-long, multi-step process. Each dog’s case is unique, so our veterinarians and staff customize individual treatment plans. For Molly, we first prescribed a tetracycline antibiotic for 30 days to weaken the heartworms. We began medication to kill the immature worms, along with an anti-inflammatory to minimize reactions. Later, we hospitalized Molly to administer injections to kill the adult worms (i.e., adulticide). For most dogs, a heartworm antigen test at the six-month mark confirms treatment was successful, but additional treatment is required to fully clear the worms in rare cases. A crucial component of Molly’s treatment plan was exercise restriction, to decrease the chance of a severe complication called verminous (i.e., worm) pulmonary embolism.

Why was Molly so sick during her heartworm treatment?

Molly’s heartworm disease unfortunately progressed to verminous pulmonary embolism, which caused labored breathing, coughing blood, and collapse. Her family restricted her activities to kennel rest and leash walks, but an embolism complication occurs in a small percentage of dogs, despite the lack of strenuous exercise. The complication risk is highest in the weeks following the adulticide injections, when the adult worms are dying. Most dogs recover after 48 hours of intensive care, and although Molly was extremely sick, because our hospital team is committed to Fear Free methods, we were able to keep her stress and anxiety to a minimum throughout her testing, diagnosis, and treatment.

How can I prevent heartworms from infecting my pets?

The good news is that heartworm prevention is simple, easy, and 100% effective. Many pet owners use monthly oral or topical medications that also prevent fleas and intestinal worms. Families whose schedule makes monthly prevention methods difficult can choose an injectable heartworm preventive that lasts six or 12 months. Check with our team, and order heartworm preventive at your convenience at our online store. By using our website’s easy prescription refill page, you never need to let your pet’s heartworm preventive lapse. 

Whether your dog has always—or never—been on heartworm prevention medication, our Gentle Touch Animal Hospital team urges that you call us. You can tour our hospital virtually before your visit, and check our website for coupons and promotions. Together, we can ensure that your pet never experiences Molly’s stress and pain.

*Molly was not a real canine patient, but heartworm cases like hers are seen every day in veterinary hospitals in Colorado and across the United States.