Sunday, March 25, 2012

Fuzzy the Saber Tooth Rabbit

Severely overgrown rabbit incisors. 
Bunnies are supposed to have "buck teeth" but their teeth are not supposed to resemble fangs (unless we're talking about literary legend Bunnicula). Malocclusion, or misalignment of teeth, is not just an unfortunate cosmetic problem. It can be an uncomfortable and life threatening disease!

Rabbits can have malocclusion or bite problems in either their incisors or cheek teeth. Incisors are the central paired top and bottom teeth. Cheek teeth are the premolars and molars beside the cheek which are used for grinding food. The incisors and cheek teeth of rabbits grow, or erupt, continuously. Normally, this growth is held in check by dental abrasion from chewing a diet high in fiber. Malocclusion issues cause overgrown teeth or razor sharp points on the cheek teeth which lead to difficulty eating, poor digestion, weight loss, drooling and painful or infected sores in the mouth.

Regular trimming of this bunny's incisors is necessary. 
At a little over 18 months of age, Fuzzy's bottom incisors had grown to nearly an inch long. Soiled, matted fur was caught in the bottom teeth. His upper incisors, not readily visible, were also too long and were starting to grow into the roof of his mouth! Fuzzy's owner had provided numerous chew toys in the hopes his teeth would naturally wear down. However, Fuzzy's severe underbite prevents him from bringing his upper and lower incisors together when he chews so the teeth do not wear down properly. Luckily, a thorough history and physical exam revealed no other significant problems. Fuzzy still had a good appetite, was passing normal stool, was a healthy weight and had a glossy hair coat. Even better, Fuzzy's malocclusion problems were limited to his incisors and his cheek teeth were normal! We were able to trim Fuzzy's upper and lower incisors during the appointment. Fuzzy will require regular tooth trimmings in the future to prevent such extreme overgrowth and secondary problems.

Rabbits are an increasingly popular pet. Proper husbandry (diet, housing, and preventive care) is essential for keeping pet bunnies happy and healthy. The Rabbit House Society offers useful information on the care and enjoyment of pet bunnies. Regular preventive care by your veterinarian is also recommended. Immediate veterinary examination is essential for pet rabbits that have not eaten in 24 hours, have diarrhea or are not defecating at all. Injury to the spine or legs, infections and parasites are also important problems. Use caution and consult your veterinarian before using any over-the-counter medications or parasite treatments because certain common antibiotics and flea treatments, for example, can be deadly to rabbits.

Sunday, March 18, 2012

Heat Wave = Heartworm Season

According to the calendar it is still technically winter. That seems impossible as we Wisconsinites enjoy another day of unseasonably warm 70-80 degree weather. Tank tops and flip flops were standard fare at the St. Patrick's Day parade yesterday. Birds and frogs loudly chirp while we lie in our beds with windows open to balmy spring-like breezes. Last night while my kids played outside we were actually beset by mosquitoes. Whatever is this March madness?

Heartworm season in Wisconsin varies each year, but it has undeniably begun a bit early this year. Pesky mosquitoes--infectious vectors for so many different diseases worldwide in humans, horses, cattle and more--are a key player in heartworm disease, a serious and potentially fatal disease in dogs and cats.  Mosquitoes suck up heartworm larvae as they feed on infected dogs. Once daily temperatures reach the high-50s, the heartworm larvae mature in the mosquito getting ready for "injection" into a new host.

After a heartworm-bearing mosquito feeds on a dog or cat, the larvae continue to mature inside this new mammal host. It takes six to seven months for the larvae to develop into adult worms which live in the heart and large blood vessels entering the lungs. In dogs, the adult heartworms reproduce, creating the microfilaria that are picked up by mosquitoes completing the cycle. Cats are a "dead-end" host for heartworms, with the life cycle being somewhat different than in dogs.

It takes several years before dogs show signs of infection, and by then disease is usually quite advanced. Heart failure and respiratory disease occur as the adult heartworms clog the heart and arteries. Reduced blood flow can cause secondary problems in the kidneys and liver. Symptoms of disease in dogs include coughing, shortness of breath, weight loss and loss of energy. Cats with heartworm disease may have chronic vomiting or symptoms of asthma. Sudden death is possible in severe cases.

A simple blood test is used to diagnose heartworm disease in dogs. Blood tests are available for feline heartworm as well, but diagnosis is more complicated due to the nature of infection in cats. Heartworm positive animals require further diagnostics such as chest x-rays and comprehensive blood tests to determine the severity of infection.

Treatment for heartworm in dogs is costly and not without risk. After receiving a series of injections to kill adult heartworms, the dog must be strictly rested for at least one month. During this period the dead adult worms are decomposing inside the dog and can cause serious problems (even death) if the dog is too active. The dog also needs to be hospitalized while starting on a heartworm preventative to kill the microfilaria. Rapid death of the microfilaria can cause severe side effects in the dog (such as anaphylactic shock and death). This is why veterinarians require a heartworm test prior to starting a dog on heartworm preventative! Remember, it takes years for dogs to appear sick from heartworm disease. 

There is no approved treatment for killing adult heartworms in cats. Amazingly some cats will spontaneously resolve infection on their own! Cats that are sick from the infection may require treatment for their symptoms.

As with most things in life, prevention of heartworm infection is cheaper, easier and safer than the "cure". There are many types of heartworm preventative available for dogs and cats. Most also treat certain intestinal worms. Some prevent flea infestations and certain kinds of mites. Ask your veterinarian for help deciding which medicine is best for your pet.

The American Heartworm Society offers good online resources on heartworm disease including detailed discussions on
Heartworm disease in dogs
Heartworm disease in cats

Sunday, March 11, 2012

Even a Corn Snake Needs a Vet

This week's veterinary adventure involved Snakey, a young corn snake who wouldn't eat. Only 12" long, little Snakey's last meal was over 6 weeks ago. A baby corn snake this size should eat once a week or so. Interestingly, baby corn snakes can be notoriously stubborn about eating and some must be trained how to eat. Yes, I said the snake must be trained. Here's how my assistant Tim and I got Snakey eating again. WARNING: Some of the photos and descriptions that follow are a bit graphic.
Snakey was visibly thin from prolonged anorexia.
If you're wondering how a snake can look thin,
you'd have to see it to believe it,
but Snakey's epaxial (back) muscles
were noticeably atrophied or shrunken. 

Corn snakes are carnivores eating rodents, small amphibians
 or other reptiles in the wild. Most pet corn snakes are bred
 in captivity, and are typically fed fresh or frozen rodents.
My assistant Tim thaws a frozen pinkie in preparation for
feeding Snakey. A pinkie is a tiny, newborn mouse bred for
this purpose.  While the pinkie appeared much too large for
Snakey's tiny mouth, the owner reported Snakey had eaten
 a whole pinkie over 6 weeks earlier.

Our first attempt at enticing Snakey with the plain thawed
pinkie was met with disinterest. In fact, Snakey seemed
a little frightened of the offering, so I proceeded
to "brain" the dead mouse. I cut into the skull to
expose the tasty brain juices. If this didn't interest
Snakey, we planned to cut up the pinkie into small pieces.
Our last ditch effort at meeting Snakey's nutritional needs
would be "gavage" or force feeding through a stomach tube.

Tim holds the pinkie mouse with a forceps and "teases"
the baby corn to stimulate its reptilian appetite. We watched in
anticipation and amazement as Snakey tasted the brain juice.
Snakey's nose never left the pinkie after that first taste,
and the little snake began to methodically feed.

Snakey's seemingly too small jaw unhinges to allow for ingestion
of the pinkie mouse. We waited with baited breath unsure if the corn
snake might change its mind at any point. We are feeding the snake
outside its enclosure to avoid accidental ingestion of bedding material.

Tim and I quietly cheer as Snakey committed
to eating the pinkie mouse. 

Notice the bulge just behind Snakey's head. Digestion of the pinkie meal
will take 2-3 days. Snakey's owner will need to learn how to "brain"
pinkies until the baby snake willingly and consistently eats these offered meals on its own. 
While baby corn snakes frequently need lessons on how to eat, the problem can be made worse from stress. Husbandry issues and over-handling are common causes of stress. Before acquiring a corn snake or other non-traditional pet (including mammals like Guinea pigs, chinchillas, etc.) thorough research into the housing, veterinary, legal and nutritional needs of your desired pet is essential. A tiny corn snake like Snakey may grow to be 5 feet long and may live more than 20 years! That is a huge commitment to make in the proper care of another living being, but as those with "exotic" pets will attest it can be a rewarding, enjoyable experience.

Sunday, March 4, 2012

Hear Ye! Hear Ye! Facts about Ear Infections

I gave my spiel on ear infections so many times this week I can't help but write it down for posterity. 

  1. Ear mites primarily cause infections in kittens or outside cats and are almost certainly not the reason your Cocker Spaniel is scratching her ears, so don't bother with the OTC ear mite remedy from the pet store.
  2. Moisture is the enemy of ears, so don't clean those dirty ears with soapy water. Dogs who get a lot of baths or swim often (especially the floppy-eared variety like Labradors) should have their ears cleaned regularly with a veterinarian-approved cleanser. These products are specially formulated, pH balanced and may contain enzymes to improve the health of the ear canal. Please don't use straight alcohol, vinegar, or hydrogen peroxide. Also, I find OTC ear wipes are completely useless for this purpose. 
  3. Another culprit behind itchy ears and infections is allergies. If your pet has a history of itchy ears at certain times of year you should discuss seasonal allergy management with your veterinarian. Finding a hypoallergenic food is tricky, and frequent diet changes without guidance from your veterinarian can lead to GI problems. Worse, over time, random exposure to many different foods may make your pet allergic to more and more ingredients!
  4. Most early ear infections involve overpopulation by yeast. Yeast love moisture after all. Over time, ears that do not receive proper treatment and never fully resolve start growing bacteria. There are many types of bacterial ear infections, with the most difficult to treat infections involving rod-shaped bacteria. That's because these types of bacteria become resistant to antibiotics quickly. If your veterinarian suspects bacterial otitis she will want to look at some ear discharge under the microscope to get an idea how aggressive therapy must be. In fact, the presence of rod-shaped bacteria often warrants bacterial culture and sensitivity testing to ensure the most effective medicines are used.
  5. The amount and type of microorganisms growing in the ear canal indicate how long treatment should be. Two weeks of treatment is a bare bones minimum!  I have seen bad bacterial otitis cases take over six weeks to clear up. For severe or chronic ear infections, rechecks by your veterinarian every two weeks is essential. I know it might seem expensive and time consuming, but if you don't follow up now you'll end up wasting a lot more money and energy on those problematic ears over time, your pet will have chronic pain and may even have diminished hearing. 

This week I gave a second opinion on Arnie, an adorable, good-natured pug whose previous veterinarian had given up hope that the chronic ear infection could be resolved and had discussed lateral ear resection with the owners. Lateral ear resection is a last ditch effort to clear up infection. The dog's ear canals are literally surgically removed! The problem is that I've treated "ear infections" in dogs who've had their ear canals removed, so it's not a sure cure. Arnie had a history of yeast otitis and microscopic evaluation of his ear gunk showed nothing but yeast. Turns out that over the course of Arnie's life the owners were prescribed one two-week ear treatment after another and the ears were never rechecked! After 10-14 days of medicine Arnie's ears felt better, the smelly brown gunk inside decreased, and the owners believed the infection was gone. I imagine Arnie's yeast enemies singing Chumbawumba's "I get knocked down, but I get up again" deep inside his ear canal about a week after the treatment stopped. 

We are currently treating Arnie with a leave-in ear treatment that eliminates the need for daily cleaning and treatment at home. Arnie's happy because he doesn't have to have his painfully inflamed ears messed with at home every day. The owners are happy because they don't have to do anything with Arnie's ears at all. I'm happy because I know the medicine is exactly where is should be and is assailing the yeast around the clock for two weeks straight (no skipped treatments, no inexpert medicating). We have a recheck appointment scheduled for two weeks, and the owners have been  prepared to expect 4-6 weeks of treatment if all goes well.  

While I fear Arnie has had a smoldering yeast otitis for years, I'm looking beyond simply killing resilient yeast to identify the underlying cause(s) of his original infection. Arnie is quite roly-poly and a breed that often suffers from allergies. He has dry skin and the fat in his face scrunches up his ears so they tend to trap moisture. I've started Arnie on a fish oil supplement, discussed weight management and questioned closely about possible food allergies. Treatment of severe, chronic ear infections and identification and management of the health conditions that cause them require patience, ingenuity and dedication. Luckily for Arnie, his family is motivated to resolve his ear problem once and for all.