My Dog Has Heartworms
By Dr. Max E. Ficken

We all know that it shouldn’t happen, but it does. Now what do we do? A positive test for heartworms is not a death sentence. New treatment methods allow us to treat many of these cases quite effectively with an excellent chance for return to normal. As with most medical conditions, the earlier the disease is diagnosed the better the chances for a good outcome.

Heartworms2Treatment involves first determining the stage of the disease and developing the best treatment plan for each case. This is called staging the disease. Staging involves a complete history from the owner, e.g., weight loss, coughing, exercise intolerance, exposure level, change in physical condition. A complete physical exam along with laboratory tests to determine the condition of the liver and kidneys and a blood count as well as radiographs to evaluate the size of the heart and changes that have occurred in the lungs and blood vessels in the chest. Depending on the findings, a decision is made to administer the treatment in a series of two injections 24 hours apart in the case of an animal with no significant signs of heartworm disease; or if the infection is more severe, a single injection is given, followed by two injections a month later. The drug “Immiticide” that is used is a derivation of arsenic which kills the heartworms over a period of 14 to 21 days.

The dead worms pass from the heart into the lung tissue where the body breaks them down and removes them from the body. During this time symptomatic treatments may be needed to control symptoms and keep the pet comfortable. During the recovery phase, activity is limited and the pet closely monitored for signs of breathing problems, coughing which could indicate pneumonia, or reactions to the worms as they die. Coughing, loss of appetite and vomiting should be reported to your veterinarian immediately. The overall success rate for the treatment of heartworm infections in this area seems to be in the range of 95%. This does not include cases that are manifesting severe clinical symptoms because of advanced heartworm disease.

There is an uncommon form of heartworm disease that involved severe liver damage following acute infections with large numbers of parasites. This form of disease carries a very poor chance for survival and is not included in the above treatment series.