Heartworm Disease

In light of a recent development this seems like a good time to discuss heartworm disease.  Because of a manufacturing issue, there is currently no effective treatment to kill adult heartworms in dogs (there never was in cats).  This makes prevention of the disease more critical than ever.

So, what is heartworm disease?  Heartworm disease is caused by a nematode parasite (Dirofilaria immitis) that is spread by the mosquito.  The mosquito picks up the larvae from an infected dog or cat, and the larvae becomes infective inside the mosquito.  When the mosquito bites another dog or cat, it injects the infective larvae which migrate eventually to the pulmonary arteries. Somewhere around 6 months after the mosquito bites the dog, the worms reach adulthood and then can produce offspring (microfilaria).  These microfilaria can then be picked up by another mosquito, and the cycle continues.  As you can see, the worms are not transmitted directly from dog to dog, or from cat to cat

How do you know if your dog or cat has heartworm disease?  Often, there are no symptoms in the early stages.  It is routine for veterinarians to test dogs for heartworms at least once yearly, so frequently, the disease is detected before the disease has progressed to the point of causing overt signs.  The heartworms, though, cause damage to the pulmonary arteries, heart, and lungs, leading to pulmonary hypertension, inflammation of the lungs, thrombosis, and signs of heart failure.  The outward symptoms of this damage are coughing, weight loss, lethargy, breathing difficulty, coughing up blood, nose bleeds, and difficulty breathing.  Some dogs will even have signs of liver disease (called caval syndrome), kidney damage, and even eye disease in rare cases.  In cats, the disease is often misdiagnosed as asthma, or may cause vomiting as the only obvious sign.  Cats may die suddenly after having the disease for a long time when the worms die.

Diagnosis of heartworm disease  in dogs is usually straightforward.  There are tests that can be run at your veterinarian that usually only take about 10 minutes.  If the test is positive, treatment will be discussed.  If the test is negative, the dog is started on heartworm preventative that is given for the rest of the dog’s life. Testing should be done every six months (even if they are on heartworm preventative).  Veterinarians are frequently asked why the tests need to be done even if heartworm preventative is religiously given.  The main reason is simply that no medication or preventative is one-hundred percent effective.  Also,  some preventatives are not safe to give if the dog already has heartworm disease.  This is not necessarily true in cats.  Cats should be tested as well, but there is no risk in putting cats on preventative if they already have the infection.  Cats usually have a very small number of worms if they have the disease, and the preventative can keep them from getting more.  Keep in mind that some companies will not honor their guarantees if the testing is not done every 6 months in dogs (or if the preventative is not purchased through a veterinarian, but that is a whole other discussion!).

Veterinarians recommend that all dogs and cats take a heartworm preventative every month for the life of the pet.  There are several products on the market ranging from monthly tablets to topical products.  Some of these products also prevent fleas and intestinal parasites as well.  It is very easy and affordable to protect you pet from this disease, and prevention should be considered to be one of the “core” requirements for keeping dogs and cats healthy.  There is also an injectable product on the market that lasts 6 months, although there are some FDA restrictions on its use.  Consult your veterinarian if you are interested in this product.

That brings us at last to the treatment of heartworm disease.  The treatment in dogs typically involves the use of a drug called melarsomine (Immiticide).  It is given either as two injections in the muscles of the lower back 24 hours apart, or as one injection followed in one month by two injections.  Hospitalization is usually required.  After treatment a period of several weeks strict rest is required. The rest period helps prevent complications such as pulmonary thromboembolism and pneumonia.  If the dog has heartworm offspring (microfilaria) in his blood, an injection of ivermectin is usually given after the rest period to kill the microfilariae.  If not, the dog is tested after three months to be sure the adult worms are dead. In cats, the disease is usually managed by controlling the symptoms, often with the use of drugs such as prednisone and bronchodilators. Once again, the drug to kill heartworms in dogs is not currently available.  Veterinarians are hoping this is a problem that will be remedied soon.

The moral of the story is that the best answer to the problem is to give your dog or cat heartworm prevention monthly and have testing done twice yearly.  It may save your pet’s life.  If you have any questions, you can call 770-422-2402 and talk to one of our staff.

Arthritis in Dogs and Cats

Osteoarthritis is a progressive, permanent, degenerative disease of the joints.  The disease occurs when there is damage to the cartilage of the joints.  The cartilage acts as a shock absorber to reduce impact on the bones.  When the cartilage is damaged, it exposes underlying bone, and pain and dysfunction result. Osteoarthritis  can occur in any joint or joints, but most frequently is seen in the hip, stifle (knee), elbow, carpus, hock, or shoulder. It results from stress or wear and tear on the joints, and may be precipitated by obesity, athletic activities, trauma or diseases such as hip or elbow dysplasia.   Osteoarthritis needs to be differentiated from other joint diseases such as rheumatoid arthritis, tick-borne diseases, trauma, septic arthritis, lupus, intervertebral disc disease (back and neck pain),  and others.

Signs of arthritis may range from very subtle to obvious.  Some dogs and cats may just be edgy and withdrawn, or might not be able to walk as far.  Others may have limping, stiffness, difficulty getting up, licking of joints, swelling of joints, or pain when touched.  Some can even become aggressive.  It is important to remember that animals do not necessarily show pain like people do, and some may even instinctively hide pain.  Therefore, it is important that your pet have regular veterinary visits, especially as they get older (although arthritis is not limited just to older pets).

Diagnosis of osteoarthritis starts with a thorough physical exam by your veterinarian.  Radiographs (x-rays) may be done next to determine which joints are involved, how severe the disease is, and to help rule out other causes of joint disease.  Usually, a blood profile is run to screen for preexisting diseases, since some of the drugs used to treat arthritis can affect organs such as the liver and kidneys. Other tests may be done if deemed necessary, such as joint taps and tests for tick-borne diseases and other less common causes of arthritis.

Radiograph of a dog with severe arthritis of the hips

Treatment of osteoarthritis depends on the severity of the disease and the underlying cause(s), and may include some or all of the following.

1.  Weight loss if your pet is overweight.  Keep this in mind- studies have shown that dogs who are normal to slightly thin may live up to two years longer than overweight dogs.

2.  Glucosamine/ chondroitin sulfate supplementation.  These products provide building blocks for joint repair, and may be anti-inflammatory as well.  They can be found alone or in combination with other supplements believed to be beneficial.

3.  Fatty acid supplementation.  Omega 3 fatty acids may decrease joint breakdown in dogs.  Several prescription diets are available with high concentrations of fatty acids.

4.  Adequan injections.  This product also provides components that are building blocks for joint repair.  The results may be faster than oral glucosamine supplementation in severely affected pets.

Products commonly used in the treatment of arthritis

5.  Controlled exercise.

6.  Therapeutic laser therapy.  Laser therapy can relieve pain, swelling, and inflammation, and increase range of motion.  It is safe, painless, and quick.  Usually it is done as a series of six treatments over three weeks, with follow-up treatments as needed.

Laser therapy being performed on a dog

7.  Non-steroidal anti-inflammatory drugs (NSAID’s) and/or other pain killers.  These drugs are a mainstay of arthritis therapy because they decrease inflammation, control pain, and increase mobility.  The risk of side effects is higher than with other treatments (they can affect the liver and kidneys, and can cause gastrointestinal ulceration), but the benefits often outweigh the risks.  Other drugs are pain killers only and may be safer in some cases, but lack the anti-inflammatory effects of the NSAID’s. Be sure to discuss the benefits and risks of drug therapy with your veterinarian.

8.  Acupuncture.

9.  Surgery.  Surgery is used to manage arthritis from cranial cruciate ligament rupture (known as “ACL tear” in people), hip dysplasia, and elbow dysplasia.

While there is no cure for osteoarthritis, significant advances have been made in slowing the progression and treating symptoms.  If you have questions, you can call and talk to one of our staff or doctors at 770-422-2402, or e-mail us at averillanimalhospital@yahoo.com.

My dog has bad breath!

One of the most common symptoms veterinarians see when performing physical exams is halitosis, which means foul odor to the breath.  When we ask pet owners if they’ve noticed their pet’s bad breath, they often say they thought it was just normal “doggie breath.”  Now,  we realize that most dogs don’t have the greatest breath, but their breath should never be foul, or fetid, as this is usually a sign of disease.

So,  what kinds of diseases can cause halitosis?  Most of the time, the cause is periodontal disease.  Other serious diseases can also cause bad breath, though, including kidney disease, diabetes, gastrointestinal disease, oral tumors, oral foreign bodies, oral injuries, and many others.  Sometimes, the problem may not be obvious on physical exam, and your veterinarian may need to run laboratory or other tests to determine the cause.  In this discussion we will focus mainly on bad breath caused by periodontal disease, and how to treat and prevent it.

Periodontal disease progresses through four stages.  Normal gingiva is pink and smooth.  In stage one periodontal disease you will see redness of the gums and some plaque and calculus buildup on the teeth (plaque is bacteria, calculus begins to form several days after plaque buildup).  In stage two, inflammation increases, and there is plaque below the gum line.  In these first two stages, professional dental cleaning and good prophylaxis can reverse the process.  In the third stage, there will be deepening of the gingival pockets around the teeth, severe inflammation, and recession of the gums (or hypertrophy in some cases).  In the last stage, there is bone loss, pus, and possibly loose teeth.  In both stage three and four, x-rays of the mouth will show bone loss.

If you suspect your dog or cat has periodontal disease, or if she just has bad breath and you’re not sure, having a veterinary exam is the first step.  If the problem truly is the teeth and gums, your veterinarian will most likely recommend a thorough professional dental cleaning first. This will remove existing plaque and calculus, and allow for a good exam of gingival pockets and the rest of the mouth.  In some cases the disease may be so minor this step might be skipped, and we will move directly to disease prevention steps.

There are many different methods and products for prevention of periodontal disease.  Probably the cheapest and most effective method is brushing your pet’s teeth.  If the teeth and gums are healthy, brushing three times per week is adequate.  To control preexisting gingivitis, daily brushing is needed.  Be sure to use animal toothpaste (they will swallow some!).  Special finger brushes are available to make brushing easier.

The next best thing to brushing are dental rinses and water additives.  These products are usually designed for daily use.  At our clinic, the most recommended product is Healthy Mouth.  Healthy Mouth is a water additive that controls plaque without chemical additives.  According to the manufacturer, it is the only dental water additive to receive the Veterinary Oral Health Council Seal of Acceptance.  The product is tasteless and free of sodium and calories.

The last category is dental chews and dental diets.  While not as good as brushing or water additives, dental chews such as the Pedigree Dentabone will control plaque in some dogs who like to chew.  They need to be used regularly to be effective.  Because obesity is such a problem in pets, we recommend that you avoid giving dental treats that are a significant source of calories. Also, some products have been associated with intestinal obstructions if large chunks are swallowed.  Dental diets are marketed by several pet food companies.  These also can be effective if used regularly, but only control plaque on the molars and premolars, not the canines and incisors.

If you have any questions or would like more information, please contact us and talk to one of our staff at 770-422-2402.

Sources:

1.  The Veterinary Information Network (vin.com)

2.  Veterinary Dental Techniques for the Small Animal Practitioner, third ed.  Halstrom, Frost, and Eisner.

Averill Animal Hospital

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