Stage 4. There is a large mass of worms which physically blocks the blood flowing back to the heart. This stage is life-threatening and requires quick surgical removal of the heartworms. However, surgery is risky and even with surgery, most dogs in this stage die.
Stage 4 – Heartworms have caused severe damage to the animals heart, lungs, liver, and kidneys. In this stage, Caval syndrome is likely. Caval syndrome is when there is such a large amount of worms blocking blood flow to the heart that it creates a sudden life-threatening problem in need of quick surgical intervention.
Adult heartworms have been known to survive inside a dog's heart for 7 years before they die on their own. Your dog does not spit them up, poop them out, or dissolve them on his own. The adult worms will live a long, productive life inside your dog's heart wreaking havoc on his heart and lungs.
As heartworm disease progresses, pets may develop heart failure and the appearance of a swollen belly due to excess fluid in the abdomen. Dogs with large numbers of heartworms can develop a sudden blockages of blood flow within the heart leading to a life-threatening form of cardiovascular collapse.
Prognosis: heartworm treatment success rates
With the three-dose adulticide protocol described above, in conjunction with doxycycline and macrocyclic lactones as recommended by the American Heartworm Society, 98% of dogs will be cleared of heartworm infection.
Dogs with no signs or mild signs of heartworm disease, such as cough or exercise intolerance, have a high success rate with treatment. More severe disease can also be successfully treated, but the possibility of complications is greater.
Treatment for heartworm can cause serious complications for your pet's health and can be potentially toxic to the dog's body. Many dogs experience soreness and swelling at the site of their injections. The most severe side effects are related to a large number of worms suddenly dying.
As heartworm disease progresses, pets may develop heart failure and the appearance of a swollen belly due to excess fluid in the abdomen. Dogs with large numbers of heartworms can develop a sudden blockages of blood flow within the heart leading to a life-threatening form of cardiovascular collapse.
With heartworm disease treatment can be extremely difficult even for the young otherwise healthy dogs but our senior dogs can see more severe side effects and death if progressed disease is present. Know that 1 in 10 dogs will develop some form of heart disease as they age.
For those who are not on heartworm prevention, it's never too late to visit your veterinarian, get tested, and start on heartworm prevention at any time.
Not all dogs with heartworm disease develop caval syndrome. However, if left untreated, heartworm disease will progress and damage the dog's heart, lungs, liver, and kidneys, eventually causing death.
Dogs that have a high number of heartworms often develop symptoms such as pronounced and persistent coughing, difficulty breathing, and exercise intolerance. In more severe cases, dogs may also experience fainting or collapse, pale mucous membranes, weakness, elevated heart rate (tachycardia) and severe lethargy.
Discussion. Hemoptysis (expectoration or coughing up of blood) has been reported as a consequence of severe heartworm infection in dogs,2-6 although it remains a relatively uncommon finding. Even fewer reports exist of dogs coughing up or vomiting up adult heartworms.
Stage 4. There is a large mass of worms which physically blocks the blood flowing back to the heart. This stage is life-threatening and requires quick surgical removal of the heartworms. However, surgery is risky and even with surgery, most dogs in this stage die.
A complication of heartworm infection, known as caval syndrome, leads to shock-like symptoms and sudden death.
Heart Worm Facts
The mosquito is the only known vector for transmitting heartworm. The average lifespan of heartworms in untreated pets is 5-7 years in dogs and 2-3 years in cats. Virtually 100% of dogs exposed to infective heartworm larvae become infected; in cats, this number drops to 61% to 90%.
Average Cost of Treatment. The average cost of heartworm treatment for dogs is often around $1,000. However, it can range from $500 to $1,100 or even more depending mainly on the size of your dog, veterinary bills, and the stage of the disease.
The L5 larvae will penetrate the small arteries in the outer parts of the lungs on their way to the heart and eventually become adult heartworms.
It is important to realize, however, that cardiogenic pulmonary edema results from left-sided heart failure, which is often caused by mitral regurgitation in veterinary patients. Heartworm disease, on the other hand, affects the right heart.
The options for a dog that remains positive after treatment depends on the animal's health status and the stage of disease at the time of diagnosis. According to some veterinary cardiologists the treatment options are either to continue a monthly preventive for six months and retest, or do another round of treatment.
After treatment, the adult worms die and are carried by the blood to the lungs where they lodge in small blood vessels. There they decompose and are absorbed by the body over a period of several months.
Allowing vigorous activity at any time in these 8 weeks can cause the weakened heartworms to shatter, causing a clot of worm fragments that blocks off blood flow to the lungs, brain, or other organs (“shaking the tree” phenomenon). This causes a stroke or sudden death.
Dogs with heartworm infections will feel weaker, and will find it harder to remain active, even in low-energy activities. Weight loss and loss of appetite. In more advanced stages of heartworm infections, your dog will find it hard to complete normal physical tasks like eating.
Is heartworm painful? - Animal Hospital of Statesville. It's not painful, per se, but they feel sick, uncomfortable, and they're likely having difficulty breathing. They're not perfusing very well, so they don't feel well.