Heartworm Treatment

Signs of Heartworm Disease

Heartworm disease is a serious and potentially fatal condition that affects dogs, cats, and up to 30 other species of mammals. It is caused by parasitic worms living in the heart and the major vessels of the lungs. The scientific name for the heartworm is Dirofilaria immitis.

Adult heartworms are 6 to 10 inches long if you stretch them out, and you can imagine what would happen if your pet’s heart and lungs get clogged up with worms.  The heart is a pump, and when it gets clogged up, heart failure is the result.

Initial signs of heartworm disease in dogs and cats can be subtle. When infected, both species may develop a chronic cough. In cats, the signs may mimic feline asthma. Cats may also die suddenly without showing any prior clinical signs. Affected dogs may have lethargy (tiredness) and exercise intolerance (refusal to exercise or difficulty exercising). Most infected dogs and cats don’t show clinical signs until the disease is advanced, so testing may be the only way to identify pets with early heartworm disease.  This is why the annual heartworm test is so important for your dog.

Treatment of Heartworm in Dogs

If infection is detected early enough, canine heartworm disease can be treated before permanent damage is done to the heart, lungs, and blood vessels. However, if the infection has been present for a long time or consists of a large number of heartworms, the risk of complications and permanent damage increase. In these cases, treatment can be more expensive and complicated, and dogs may need many months to recover from the infection as juvenile and adult worms are cleared from their systems. Hospitalization may be required.

The goal of treating heartworm disease in dogs is to remove all stages of the parasite (including adult, larvae, and an immature stages known as microfilariae) and improve the pet’s condition without causing treatment complications. First, your veterinarian will conduct a series of diagnostic tests to determine which stages of heartworms are present. During this time, your veterinarian may also perform tests to reveal how much damage (if any) has already been done to your dog’s heart, lungs, and blood vessels as a result of being infected. After administering treatment for heartworm disease, your veterinarian will recommend follow-up testing to ensure that the infection has resolved. Some dogs may need to be treated more than once to clear the infection.

If significant damage to a dog’s heart, lungs, and vessels has already occurred, permanent health issues may remain, even after the heartworm infection is successfully treated. Dogs exhibiting severe clinical signs may first need to be stabilized with steroids and other medications before administration of medication to kill heartworms. Additional medications may also play a helpful role in supporting dogs whose heart and lungs have sustained permanent damage from heartworm disease.

During treatment, unnecessary stress on an infected dog’s cardiopulmonary system (heart and lungs) should be avoided as the adult worms die. Depending on your dog’s condition, your veterinarian may recommend hospitalization. When your dog comes home, exercise restriction will likely be recommended for a period of time to avoid overly stressing the cardiopulmonary system. Your veterinarian can discuss additional recommendations for monitoring and caring for your dog during and after treatment of heartworm disease.

Treatment of Heartworm in Cats

In cats, there is no safe and effective medical treatment to eliminate heartworms once they are present.  This is why prevention is so important. Your veterinarian can discuss with you how best to monitor your cat and manage the signs of heartworm disease. Antibiotics, steroids, and other medications are sometimes recommended. For cats with severe breathing problems or other complications, hospitalization may be needed.