Diseases

Chemotherapy in Lymphoma

/ Dr. Christine McFadden / Leave a comment

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November 30, 2015
Chemotherapy is a long word. The definition doesn’t do justice to the fear derived from a term that means only “chemical treatment”. In reality, “chemotherapy” is a word primarily used for a group of cytotoxic drugs, cell killing medicine used in the treatment of cancers. Cancer is a disease that can occur in any body part, any cell line of the body. Cancer occurs when that particular type of cell goes haywire and starts to divide abnormally, faster and faster, so these abnormal cells become a big mass that invades and overgrows the normal healthy cells. This abnormal mass of cells will eventually infiltrate, overwhelm, and kill the normal cells of the organ or body part they grew from. Finding medicine to combat all the different types of cancer that occur is a challenging job, and the drugs used often come with side effects which are themselves feared.

“Ruby” is a beautiful mahogany coated Irish Setter. She’s a little over 7 years old now, and enjoyed some success in the show ring when she was younger. Her owners bred her after careful consideration and her pups were highly sought after. She was retired from the show ring and breeding and had been happily ensconced as a beloved house pet for many years when one night while brushing her out her owners noted two firm lumps along her jaw line. They didn’t seem painful to Ruby, but on closer examination it looked a little like she had human Mumps. Ruby ate all her dinner that night and was playful on her walk but they decided to get this checked out anyway.

We saw her two days later and found things much as her owners reported. Bright eyed, active, in good weight, Ruby was playful for her exam. Pressure on the swellings below her jaw seemed a bit uncomfortable – she wiggled backwards during that part of the exam. The swellings were located where the back of the mandible, or jaw, meets the neck, a common site for lymph nodes. Lymph nodes filter lymph, a body fluid, cleaning it of bacteria and other toxins before the lymph is returned to the general blood stream. As sentinels for infection trying to enter the body, many kinds of disease might cause them to swell up a bit as they swing into action to defend the body. Ruby was examined along the several key points of external lymph nodes found over her body. We detected two more suspect lymph nodes that seemed enlarged.

As with so much of medicine, there is a standard protocol that is usually initiated, sort of the building blocks of investigation into diagnosing a disease. These steps cannot be lightly skipped, as one should always start out looking for the most common of problems and adding on further tests as deemed necessary to answer and understand the disease completely.

On this day we recommended performing needle aspirates of the masses and a blood panel.  A needle aspirate is a straightforward procedure: a needle is attached to a medium sized syringe and gently inserted into the antiseptically cleaned mass in question. The syringe must be large enough to exert enough suction to withdraw a sampling of cells from the mass. Sometimes liquid is present, sometimes nothing appears to come back into the syringe. The needle is carefully separated and then the open syringe reattached to “blow” the cells collected onto clean glass slides. These slides will be stained and examined at the laboratory to identify WHAT the mass is, if there are signs of infection, abnormal cells, perhaps what type of organ it is from. The blood panel does a general check for all body systems and functions, though it will not detect a specific cancer (barring a blood cancer leukemia).

Ruby’s aspirate confirmed that the masses under her jaw were her lymph nodes. In a normal adult dog over 80% of the lymphocyte cells are small, round “Mature” cells. In Ruby’s aspirate more than 50 % were big immature blobs of cells. Ruby’s blood panel was actually normal. Additional tests of x-rays and an abdominal ultrasound were recommended to check for enlargement of any internal lymph nodes. Her chest x-rays were clean, but the abdominal ultrasound revealed another enlarged node.

These tests were completed in less than a week. With this information we were able to stage Ruby’s Lymphoma cancer and she was considered a good candidate for chemotherapy. This started as a once a week treatment as she cycled through four different medications each month. Vincristine, Doxorubicin, cyclophosamide, asparaginase and prednisone may all be used in the treatment of Canine Lymphoma. Side effects from the chemotherapy can include the same kinds of problems many people report, such as nausea, vomiting, diarrhea, hair loss and worse. The reality is that we treat multiple dogs and cats with chemotherapy for a variety of cancers every year and rarely see discomfort from these things. This is a blessing for both pet and owner and allows us to both recommend and administer chemotherapy comfortably.

Within 2 weeks the lymph nodes under Ruby’s jaw had dramatically returned to normal size. Her owners were unable to tell that she was on medication of any kind, except for a healthier appetite spurred by the prednisone, a steroid. Without chemotherapy, Ruby might have lived 90 days. Although chemotherapy has put Ruby in remission, it is not a permanent cure, and she still requires treatment every couple of weeks, but Ruby is an 8 month cancer survivor and going strong!

Christine B. McFadden, DVM
drmc@mcmenagerie.com

 

KCS or Dry Eye

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November 16, 2015
His name was Chipotle. A mismatch for a name if ever I saw one. The timid salt-and-pepper curly coated little Shih Tzu weighed in under 20 pounds and his tail trailed after him over the floor as he puttered around the exam room. Happily I noted that he wasn’t sweeping up any dust balls. There was nothing of a fiery chili pepper about him and I wondered briefly how he got his name. Then he looked up at me. Oh dear. Under long eyelashes I could only see matted hair and mucous covering what should have been his luminous eyes.

I scooped him up and brought him closer to me on the exam table. He stood quietly, the little feather duster tail wagging slowly as he gazed blindly up at me. Both eyes were covered by a sticky, thick layer of mucoid film, which covered a thick coat of brown pigment overlying the corneas. The whites of his eyes were streaked red from inflammation. They looked very painful. Chipotle cocked his head as I bent over him, using an ophthalmoscope (kind of a fancy flashlight) attempting in vain to penetrate deep into the back, or fundus of his eye, where the optic nerve is. But the pigment was so thick over his eyes that I couldn’t see more deeply.

I finished his examination, noting that he also had a chronic ear infection but that over-all he was in good shape, with an excellent weight and coat. I turned to his owner, an earnest man who had recently relocated to our town and was very anxious to find out what was wrong with his dog. To my surprise, he had actually been treating the dog with a prescribed medication. The owner knew it wasn’t working. He had been using it for so long I wasn’t sure if the original problems with the dog’s eye condition might have started out as something else and now changed. Certainly this medication was not effective.

I explained to Chipotle’s owner my thoughts about his eye lesions and discussed the diagnostic tests we needed to perform. First on my list was a Schirmer tear test. Special tiny strips of sterile absorbent paper are gently placed just inside the eyelid for 60 seconds. The paper wicks up the liquid in the pet’s tears. The strips are measured in millimeters, already marked on the strips. Anything over 15 millimeters in 60 seconds is normal. Anything less than 10 mm is suspect for a condition called “Dry Eye” or Keratoconjunctivitis sicca (KCS).

KCS is a horrible condition. For reasons often unknown, frequently ascribed to a problem with the immune system, the dog’s eyes have stopped producing tears from the lacrimal glands. In normal eyes, every time a pet blinks the surface of the eye, the cornea, is covered by a thin film of tears that keeps the cornea moist. Without tears the cornea dries up. Ulcers or holes in the corneal surface may occur. Over time brown pigment covers the dried cornea and that thick ropey mucous appears. The dog will go blind. Every bit of this process is extremely painful.

Chipotle flunked his Schirmer’s tear test. His right eye had a score of 2 mm, his left zero. We also ran a blood panel to rule out immune associated disorders like thyroid disease, diabetes mellitus, lupus and other diseases. Chipotle’s blood tests did not show a clear cause for his KCS.

The recommendations for Chipotle were to clean his eyes of the thick mucous at least twice a day with a sterile saline solution, found in over-the-counter contact lens cleaning products. This would allow his topical eye medications specific for KCS to penetrate better. There are at least two medications used to stimulate tear production in the dog (sadly, they are not terribly effective for the rare cats who develop this disease) : cyclosporine and tacrolimus. Both require twice daily application for the rest of the dog’s life. Eye infections, ulcers or other secondary corneal diseases may require additional topical medications. It’s a daunting prospect to face the requirement to treat your dog twice daily, every day, forever – or he’ll go blind.

Chipotle’s owner was committed to his little dog, but seemed apprehensive about actually using the medication. “He’s mean”, he said. Huh? This little droopy dog? Since I do this for a living I offered to demonstrate how to apply the medication. Which was the precise moment that Chipotle earned his name, as he came to life with a fierce burst of barks. Fiery indeed! Shih Tzu’s are blessed with small, rounded teeth and I’d be pretty embarrassed to be bitten by one (did I put that in writing?). It wasn’t too hard to devise a treatment method and off they went. On recheck 4 weeks later I was startled by the transformation in this little dog! His corneas were still covered by the brown pigment, though that would thin over the coming year, but the mucous was gone. His Tear test was over 15 mm in both eyes. Clearly the pain was gone, as Chipotle bounced all over the room, tail swishing wildly. Most miraculous of all, his bad temper at home about “medicine time” was gone and his owner confirmed that he had his “old dog back”.

Christine B. McFadden, DVM
drmc@mcmenagerie.com

 

Atresia Ani and Medical Jargon

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October 27, 2015
They say communication is the key to understanding. Hmph! Many years ago I was in conversation with a Southern grandmother. “I like Datsuns”, she told me. Encouraged by this opening, I nodded in agreement, saying that I believed both the Datsun and Toyota cars to be very dependable. Warming to the subject, I began to share a story about my Aunt Bea’s wonderful little car when the woman interrupted me, frowning. “I was talkin’ about Datsun DOGS”! There was a beat of silence. “Oh, oh, of course, Dachshunds!” I spluttered. I can’t remember the rest of that conversation for the life of me, but it was only one of many lessons I absorbed over the years as I’ve struggled to explain pet maladies and medical eccentricities to my clients….

The elderly woman sat expectantly in the client seat we provided in our exam room. In my hands I held a tiny eight day old puppy. She had brought the puppy to me because it had stopped nursing that day and she was quite anxious that all go well for her charge. I examined him, checking the roof of his mouth for a cleft palate or other deformity. His ears were pressed tight to his head, his eyes still unopened. His heart sounded normal. The puppy appeared to have been eating well, with a full, rounded tummy. As I lifted up his tail my eyes stopped. I carefully twirled him in my hands for a closer inspection. The skin under his tail was smooth, unbroken by any opening that should have been there.

Oh. I looked over at his owner, still sitting up straight in her chair, a kind smile upon her face. As our eyes met she appealed to me, “Do you know what’s wrong?” I nodded slowly, my mind racing over the possibilities for treatment and successful outcome. Because I could think of none, I was slow to respond.

“Your puppy has a congenital defect, Atresia Ani,” I replied.

The woman’s smile widened. “Good, so you can fix him?”

I realized that my medical diagnosis made no sense to her – oh, so many hard-earned terms thrown out the window over the years, as I struggled to re-phrase body diseases into language comprehensible to all! I stared at this good woman fixedly and tried again. “You see, he was born without an anus.”

I must have been rocking in my agitation, as the woman began to gently move backwards and forwards in slow rhythm to match. “Yes”, she nodded, “I’m glad you can help him. When will he be better?”

The pressure was unbearable as I realized I still had not conveyed his diagnosis to her. Another tense silence and I suddenly blurted out “Your puppy was born without an asshole!”

Shock at my language and immediate comprehension registered in her eyes. The smile faded. Neonatal medicine was rudimentary thirty years ago in veterinary medicine. The condition of Atresia Ani is found in newborn puppies, a congenital defect characterized by the malformation or even complete lack of an anus. The intestine cannot empty. The puppy cannot defecate. Feces builds up inside, bloating the belly. Death ensues. Atresia Ani is rare, but when seen is more commonly found in female dogs of the Boston Terrier or small Poodle breeds. Surgical correction is not simple : the tube of intestine, the rectum, cannot just be connected to a newly created opening in the skin to connect the two. Without an anal sphincter there is no way to open and close, no way to regulate defecation. Feces will drip out at any time, called fecal incontinence. This is not appealing to most pet owners, faced with a lifetime of diapers, careful hygiene and skin care.  In extreme cases of Atresia Ani part of the intestine may not have developed at all. To asses a case for surgery requires in-depth radiographic study. In addition, one must be certain no other congenital defects exist which would adversely affect the outcome. This case was entirely beyond the scope of a general practitioner and seemed unthinkable in a patient weighing less than 150 grams. How the puppy survived for so many days was itself a sad miracle. The puppy was being poisoned by the body waste he couldn’t eliminate and I had to recommend humane euthanasia. The client was lovely about it, though saddened that we could not help her puppy. There were other healthy, thriving puppies at home. But it was this little one that needed her care who had tugged at her heartstrings. I remember her fondly, and her puppy, of no particular importance to the world, but he mattered to her and she made his short life matter to me.

Christine B. McFadden, DVM
drmc@mcmenagerie.com

 

Uric Acid Stones and Spotty the Dalmatian

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Dr Mc Blog

August 12, 2015
Well if you don’t know that “Spotty” is the perfect name for a Dalmation dog then you’re not a kid. Clarity is not reserved to children, but I find they are less likely to obfuscate descriptive terms. And a Dalmatian dog, though born white, is soon covered with a myriad of black (or brown) spots. This breed has been beloved for centuries, serving as a watch dog, a fire station dog and starring in a famous Disney movie. Going back to their origins, they were selected for their beautiful coats and rugged nature to accompany coaches, travelling long distances as guards. This led to them serving horse-drawn fire wagons, as they could keep up with the horses, barking an alert to clear people out of the way. At the scene of the fire they both calmed the horses and guarded the wagon. One tough, sturdy breed of dog. Despite the movie (all puppies are cute), Dalmatians are a breed highly unsuitable to be penned up in a house with little to do. No action hero likes to be sidelined. But the Dalmation mania has subsided and these days we see dogs well suited to their homes. Some even belong to firefighters!

Spotty was a family pet. He had recently celebrated his fifth birthday. He looked forward to his daily bowl of kibble and walk in the park. But….something seemed a little off. Spotty passed on his kibble one night and at the park he seemed to strain to urinate. In fact, he’d walk a few paces and lift his leg, but nothing came out. By the next morning Spotty wasn’t walking very well. His hind legs seemed stiff and he was panting and anxious. Sometimes his stomach would heave and it was hard to tell if he was trying to vomit or urinate but nothing came out either end. Spotty seemed painful. Time to go to the vet.

In the hospital it was obvious Spotty was in distress from a distance. Panting and unwilling to walk, the reason was soon obvious. His abdomen was mildly distended and palpation identified a very large, firm bladder. It hurt to touch and Spotty was in no mood to be brave. We had a strong suspicion as to the cause of Spotty’s problem.

You see, the Dalmatian breed of dog has a unique inherited predisposition to uric acid bladder stones. Foods like organ meat or seafood are high in a form of protein called purines. The liver is supposed to break this protein down into a harmless substance that the body absorbs but in Dalmatians, lacking this gene, the liver only processes the protein into uric acid, which is filtered through the kidneys and settles out as small stones (as hard as coarse sand) into the bladder. The best way I can draw this picture with words is to compare the Dalmatian, a mammal, to birds. Birds are uricotelic, meaning they do not break down body waste into urine but instead their kidneys excrete uric acid, the solid white matter you see in a bird dropping. This is normal for a bird. But mammals – dogs – are supposed to excrete waste filtered through the kidneys as a thin fluid, urine. Dalmatian dogs make urine, but some will also make uric acid crystals which build up in the kidneys and bladder. Hundreds of these crystals can be deposited inside the bladder and obstruct the male Dalmatian dog’s ability to urinate. Once the bladder outlet is obstructed the dog can’t urinate and the bladder will slowly fill as the kidneys continue to produce both urine and uric acid. Without relief of the obstruction the bladder will rupture and/or the kidneys shut down, both potentially leading to death.

Spotty’s abdominal x-ray showed an enormous bladder, though the uric acid stones causing the problem weren’t well defined. His bloodwork demonstrated kidney distress, but within parameters that we felt could be reversed to normal once his obstruction was surgically cleared. We whisked Spotty in for emergency surgery, relieving his obstruction and emptying his bladder of hundreds of tiny grey stones. Intravenous fluids helped get his kidneys up and running again, a process we call diuresis. The stones or uroliths were analyzed to be certain they were uric acid in nature and a proper prevention plan put in place.

We know that high protein, meat-based diets may not be the best choice for any Dalmatian at this time as many are formulated with high purine foods of organ meat or seafood. Avoiding these purine-rich foods puts less burden on the liver and can greatly decrease the formation of stones. Dietary avoidance of these foods is a cornerstone to prevention.

This condition is similar to the disease of gout in people. In people the uric acid crystals settle in the joints, causing inflammation and pain. Interestingly, the same medication may be used to treat both humans and canines.

Spotty is lucky. Through a low-protein, non-meat based diet, medication and monitoring of his urine he is expected to lead a full, normal life. Because the gene has been identified, Dalmatian breeders can now specifically test and work to breed out this genetic mutation. The Veterinary Genetics Lab at the University of California, Davis, School of Veterinary Medicine offers genetic testing for a variety of breed-inherited diseases.

Christine B. McFadden, DVM
drmc@mcmenagerie.com

 

Cat Scratch Fever

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Dr Mc Blog

July 9, 2015
My mother wanted more articles on cats, but this time she’s gone too far. While her cats swirled about her feet in a breakfast feeding frenzy one nudged her along a little too hard, breaking skin. Three days later she almost landed in the hospital as her leg swelled up, an angry red color.

Diagnosis : Cat Scratch Fever.

Cat Scratch Fever, more properly Cat Scratch Disease, is caused by a little known bacteria, Bartonella henselae. Because cats themselves rarely suffer any effects from this bacteria, your veterinarian is not “looking” for it. Oddly enough, statistics from the Center for Disease Control (CDC) in Georgia report that up to 40 % of cats may harbor this bacteria on their claws or teeth sometime during their life, with the most likely period being when they are kittens. This, of course, is when young cats are most playful, most likely to play bite or scratch during a wrestling match. If your skin is broken the Bartonella bacteria has an opportunity to start an infection in you – the human. The cat will be fine.

Even more oddly, your cat probably picked the bacteria up when it was scratching at a flea! Infected fleas carry the bacteria, and your cat will get flea dirt caught under its nails or in its’ teeth. Once a person’s skin is broken, the bacteria is transmitted through the saliva or from under the cats nail. Even allowing a cat to lick an open wound which you may have (irritated mosquito bite?) may transfer the bacteria. We’re back to flea control, again! In our mild climate, fleas are a reality year round in Merced. If you think you have them under control, keep treating – keep it that way!

Washing any scratch or bite wound will prevent most people from developing an infection. Once Bartonella has taken hold, it can be readily treated with antibiotics by your physician. Your cat does not require treatment. On rare occasion an infection with Bartonella can land a person in the hospital for intensive care.

Does Bartonella EVER bother the cat? Maybe. There are tests to demonstrate if anti-Bartonella antibodies are present in the blood stream. This only proves exposure to the bacteria, not current infection. Rarely an ill cat, perhaps with an eye infection, may be tested for Bartonella. If you have high concern about acquiring a new cat or are faced with a family member who is immunocompromised and must guard against any disease encounter you can request these tests for your cat and even a course of treatment as a preventative, though it can’t guarantee against future re-infections.

My mothers’ cats are on flea control and are older, but one of them goes outdoors and inevitably brings fleas back into the house. I knew the source of infection and how to contain it. I must admit it was interesting to follow how her physician handled it. As a veterinarian, I am familiar with the rejection one must inevitably face when serving in a “helping profession”. Everyone wants to help. They want to help even more when it’s outside their scope of expertise – it’s so tempting to give advice! I am sometimes the last stop in a desperate quest to heal a pet, after the owner has purchased a variety of compelling exotic potions over-the-counter or whipped up a guaranteed home remedy recommended by the neighbor’s cousin passing through town.  My mothers’ leg improved slowly but surely under the extremely watchful eye of her physician (he even offered to make a house call to check on her over the weekend). So it was with some interest as I followed her recovery to hear her inform me that she was going to have the gardener check her leg that day. That gave me pause. I double-checked. The gardener? I silently chewed this over in my mind. She was seeing her physician every other day, if not daily. Her veterinarian daughter was stopping by every night. The gardener?  It felt good to know these things didn’t happen just to me. I wondered if the gardener would argue the merits of herbal remedies….? I could tell this was a turning point for the better in her case and that I could step out now. And her physician? A miraculous cure. My hat’s off to you, Dr. De La Pena.

Christine B. McFadden, DVM
drmc@mcmenagerie.com
Valley Animal Hospital, Merced

Canine Distemper

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Dr Mc Blog

June 24, 2015
There has been much dialogue and soul searching among the people of California after an outbreak of human measles occurred last Christmas. The source of contagion was traced to a child visiting Disneyland. Ultimately over 100 people were affected across many states. Part of the controversy? There is a preventative vaccine against measles, but many of these sick children had not received it. You see, there is a group of people who are opposed to vaccinations (immunization) for children. Some believed measles to have been “eradicated” in the United States since 2000. The problem is, we don’t live in a bubble. We share our earth with an ever-changing flux of people. Exposure to other people’s viruses and bacteria is as simple as going to the grocery store, sight-seeing in San Francisco, a vacation to an exotic locale. I repeat, we do not live in a tidy self-preserved bubble (gated community attempts aside).

Neither does your dog. So let’s talk about the canine distemper virus, which most of todays’ veterinarians in the big cities have never seen. Come practice in Merced County. Where, simply because of the lack of proper vaccination starting between 6 to 8 weeks of age, we do in fact see this disease. Puppies are at highest risk because of their still-developing immune system, but even older unvaccinated dogs can contract distemper. Did you know that the Canine Distemper virus is actually a relative of the human measles virus? (Your dog cannot make you sick).

The virus is passed directly from one infected dog to another, often by a cough or snotty nose sprayed into the face of another dog. Surprisingly, the virus doesn’t live long in the environment by itself, but people can transmit it accidentally if they’re handling one puppy’s sick nose and spread its mucous to another dog through petting – dogs always run up to you nose first, right?

The first signs of illness start 10 to 14 days after initial exposure to another sick dog. Your dog might have a horrible runny nose, goopy eyes and a deep cough. In the early stages the dog may run a very high fever, 105 degrees or more. It is always on our list of rule-outs for a coughing dog. If we are secure that your puppy is properly vaccinated we will place it lower on our list, but not eliminate distemper entirely. Definitive laboratory diagnosis can be difficult. When clinical signs are present, both blood tests and an oral cheek swab of saliva can aid in the diagnosis of distemper.

There are more than one strain of distemper viruses, some more virulent than others. Sometimes the virus moves quickly through its phases, sometimes an owner believes their pet has recovered, only to come down with “new” and very serious problems 2 to 3 months later. There is no cure for Distemper.

After the upper respiratory signs, the virus may affect the gastrointestinal tract. The “gastro” part or stomach responds by vomiting. The intestinal part responds with diarrhea. The dog is miserable and dehydration and weight loss are quick to follow. Many dogs die at this stage.

If the dog’s body continues to fight, the virus may attack the nervous system, creating palsies and seizures. One particular seizure is called the “chewing gum fit” – it looks as if the dog is chewing gum as its jaws work up and down. This a pathognomonic (classic, diagnostic) seizure disorder of Canine Distemper.

Once neurological signs are seen the dog is not expected to ever fully recover; though some may be partially stabilized with anti-convulsant medications, other will carry a twitching paw or be prone to seizures for the rest of their life. More than 80% of affected puppies and non-vaccinated older dogs who contract this disease will die of it. The survivors may never be wholly healthy.

And all this for lack of a vaccine. Even dogs enjoy getting together for the good times with their fellow doggie and human friends! Whether your dog is a globetrotter or a stay-at-home please protect your pets : Vaccinate your loved ones.

Christine B. McFadden, DVM
drmc@mcmenagerie.com
Valley Animal Hospital, Merced

Pretzel and the Dislocating Knee

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April 7, 2015
“Call me Pretzel”, the note said. I peered over the top of it to look at my patient. She was aptly named, wriggling and dancing on the exam table, tongue flashing as she air kissed in happy anticipation of meeting me. “Well, alright then! Pleased to meet you, Pretzel!” I greeted her. With a surge of energy she tried to jump towards me and instead collapsed in a heap as her back leg buckled under her. I righted her with one hand and glanced at her chart again. “Sometimes lame” it read.

I looked again at Pretzel, a little toy breed dog weighing less than 10 pounds. She was just over 1 year of age. Her owner reported that although her little dog usually ran around happily, recently she had noticed that sometimes she picked up one of her back legs when running, or might kick it out behind her then resume her pace. Pretzel didn’t like to jump as much as she used to, and occasionally gave a little cry when landing on her rear legs. As I examined her, I gently pressed on her tiny kneecaps, or patella’s, and felt the right kneecap slip out of place, bumping over the groove at the bottom of the upper thigh bone, the femur, that was supposed to hold it in place. The kneecap slid to the inside of her leg – but as soon as I straightened the leg, it popped back into place. Diagnosis : Luxating patella, also called a dislocating kneecap.

Dislocating kneecaps are very common in many toy breeds. In some breeds it is estimated that over 50% of all puppies are so afflicted, a hereditary predisposition that is evident by a year of age or sooner. Some people believe that as these toy breeds are bred for ever smaller “extreme” sizes more anatomical problems crop up. Certainly these dogs were bred for looks, as lap companions and not as “working dogs” –  attention to strong teeth, big muscles and performance were not a first priority.

The knee of a dog is an interesting joint, being very similar to that of a human in general construction. Kind of bony, it is held together by tendons and ligaments, without much muscle to cover and protect it. Hard working, it must flex and bend with every step taken, as the entire backside of the body is supported on it. So can you picture all this? The big heavy femur with this small sliding patellar bone-and-ligament-show that connects and allows bending when attached to the lower tibia/calf bone. What keeps the patella in place? It is supposed to be nestled deep in the valley of the femoral groove, and helped to stay there by being firmly attached in a straight line to the bony ridge of the tibial crest below it.

In toy breeds, the femoral groove is often formed FLAT. Imagine! With nothing to cup it, the patella is at the mercy of the inner pull of the thigh muscles and off it goes, dislocating sideways towards the inside of the knee. Because the dog was born that way, it doesn’t know that that’s not the way it should be; truthfully, although they walk a little oddly, most young dogs don’t show serious discomfort. But as the patella bobs back and forth over the rim of the distal femur, it rubs ever so slightly, just a touch of friction….and eventually arthritis. At first just a little breakdown of the cartilage covering the bone. Over time, as year pass, from an erosion of the cartilage little pits and bumps appear and the knee becomes more painful. Eventually some dogs become so crippled they can no longer use the leg at all. Surgery is too late by then.

Pretzel, happily, was young and could benefit greatly from corrective surgery. It was easy to recommend it – all the telltale signs were there, from the hard pop when her knee dislocated (painful!) to the changes in activity her owner recognized at home. After x-rays to be certain she had no other orthopedic problems that might affect the outcome and to document the flattened femoral groove, she was taken to surgery – there is no other remedy for such a knee – and her knee rebuilt. A new groove was fashioned deep into the femur and the surrounding joint capsule and ligaments were tightened to hold it in place while healing. Although Pretzel’s leg was straight, in some crooked-legged breeds the tibial crest will also be transplanted.

In case you’re wondering, large breed dogs also can develop dislocating knees, though for most it is caused by some kind of accident or trauma. Surgery is always a necessity in these cases.

During surgery we looked at her original bone, where a thin line of angry red could be seen on the inside rim where Pretzel’s patella had been rubbing as it popped back and forth. We couldn’t undo that damage, but we could stop it right there, and with no further rubbing there was a good chance she would have minimal arthritis in that joint as she aged. Once the groove was deepened, the kneecap sat firmly in place! Pretzel awakened to a fully functional knee for the first time in her life. Helped by anti-inflammatory and pain medications she was walking gingerly in the first few days; had her stitches out by the second week, and began swimming in her bathtub at home as a form of non-weight bearing physical therapy. Within 6 weeks Pretzel was flying across rooms again, taking couches in a single bound, and dispensing crazy doggie kisses to all comers.

Christine B. McFadden, DVM
Valley Animal Hospital, Merced

Heartworm

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Dr Mc Blog

March 24, 2015
Moonshadow gently waved his tail from side to side, tongue pink as he greeted us. The older black lab moved with a stately grace across the exam room, a gentle cough escaping from his throat. “There, did you hear that? Why is he coughing like that?”, his owner queried anxiously. I stared down at him, mind running through possibilities. Moonshadow was old, so I had to put cancer on the list. Not a happy place to start. I said nothing as I began a full exam, checking out his teeth, moving over areas where lymph nodes lurked, probing his tummy, riffling through his fur. Moonshadow cooperated with everything, seeming to enjoy it all as one big petting fest. I pulled out my stethoscope and listened carefully to his chest, timing his heart rate and listening to his lungs expand and contract with each breath. A lot of times you don’t hear much listening to healthy lungs, maybe a quiet whoosh. Today I was hearing crackles and rales, sort of like Rice Krispy cereal when you first pour the milk on. Not a good thing to hear. I stood up from the floor where I’d been kneeling at Moonshadow’s side. He side-swiped me with a lick of appreciation, then coughed gently with the extra effort. His owner, in her late twenties, shifted from foot to foot anxiously. “We’ve been through so much together. He’s travelled across the country with me.” Her voice trailed off, tears threatening. Her dog walked over to her and pushed his head up under her hand.

I asked to run a blood panel and take a set of chest x-rays. The x-rays would show me any masses in his chest that could be cancerous or might point to an odd disease like the fungal infection Valley Fever. I could evaluate his heart size and shape and find markers for other lung diseases. The bloodwork would check for signs of infection, diabetes, thyroid disorders and see if his liver and kidneys were functioning ok. Not much point in making a diagnosis of one problem and later finding out that my patient’s renal function was toast. Obtaining a complete picture up front was in the best interests of my patient so I could help him – or know that I couldn’t, should that be the case.

One of the blood tests was for Heartworm, Dirofilaria immitis, a long spaghetti-like worm that lives in the blood stream, bobbing around through little capillaries and veins as larvae until they eventually grow up and take up residence in the lungs and heart. There can a fistful of worms clogging the heart. Nothing microscopic about it – unfortunately, the patient is usually dead when you get to see it that graphically.

Heartworm goes through one of its life stages in the mosquito. It is when the mosquito bites your dog, sucking out a bit of blood (the mosquito’s meal) that it injects the microscopic larval form of Dirofilaria into your pets’ bloodstream. If you give your dog the heartworm preventative EACH MONTH it kills off all first-stage larvae encountered and the story ends there. If your dog isn’t protected by a heartworm preventative, or you forget to give it for a couple weeks (even if you re-start it and get back on track), then there is a window of opportunity for the first-stage larvae to grow on to the second stage and into the adult worms living in the chest. The whole process from mosquito bite to worms clogging the lungs and heart can take up to 2 years. The symptoms your pet shows may range from something mild like restless sleeping to wheezing to full out coughing and heart failure.

Todays’ tests are very sophisticated, requiring only a few drops of blood to detect antigen, the bodies’ response to invasion by a foreign invader, in this case the heart worm. If your dog does test positive for heartworm, a second test is done to look for actual microfilaria larvae circulating in the blood, which helps stage the disease progression and predict the prognosis for your pets chances of beating this disease.

Is there a treatment for dogs that have heartworm? Yes, an injectable form of arsenic. Can some dogs die from the treatment or get very sick from it? Yes. Does the treatment work 100% all the time? No. Once a dog has had heartworm and been successfully treated do its lungs go back to normal? It depends. Sometimes. Can cats get heartworm? Yes, statistically 5-10% as often as the dogs in a given area of California.

In February 2015 there were two (2) cases of heartworm diagnosed in local dogs : a little Yorkie in Merced and a medium sized dog that lives in Atwater. Both are house pets and neither has ever travelled outside of town. For years we have known that pets that travel to the foothills, such as Mariposa or Sonora, are at very high risk; also the Delta area of Stockton. Most of the United States is infiltrated, so ALL travelling dogs and cats should be on monthly preventative. Heartworm is HERE in Merced County. Most dogs can be protected for less than $100 a year. Talk to your veterinarian about the best choices for your pet and family.

And Moonshadow? He tolerated the arsenic treatments. His lungs were permanently damaged and he needed medicine for the rest of his life to keep the post-heartworm immune reaction under control. He was a dog that appreciated everything done for him and gave another two years of love to all he met in his journey through life.

Christine B. McFadden, DVM
drmc@mcmenagerie.com
Valley Animal Hospital, Merced

 

 

Fleas Part Two : Is Zero Tolerance Possible?

/ Dr. Christine McFadden / Leave a comment

Dr Mc Blog

September 14, 2014
In my previous column on fleas we discussed the mode of action and the suffering and disease which fleas inflict upon dogs, cats, and occasionally people.  I stated that the tapeworm of dogs, Diplydium caninum, did not infect people. Dr. Jerry Menefee of Los Banos called to tell me how much he enjoyed my column and to gently correct me: there have been a few cases of human infestation with the dog tapeworm, called Diplydiasis, primarily when a young child or infant has actually eaten an infected flea (same as the dog or cat) and the worm develops in their intestine. There is rarely any sign of illness, just little tapeworm segments passing in the diaper! Treament for the child is the same as used for the dog, with excellent success. I could find 2 medical papers printed on separate cases, one published in 1993, another in 2003. Diplydiasis appears to be extremely rare (but oh dear, aren’t you running to check the calendar to see if you’re up to date on your flea control?); I shall expose the mysteries of “human tapeworm”, an entirely different group of worms, in a future column. Today we are exploring methods of flea prevention, critical in our area because, as noted in Part One, our local climate favors fleas – we are a flea hospitality haven!

If a pest has been around this long, there’s been plenty of time to try to get rid of it. Because some pets and people seem to attract more than their fair share of attention and get more bites, researchers tried changing the way skin smells. As it turns out, fleas are NOT put off by garlic or B vitamins, nor are they scared away by clove oil, tea tree oil, cinnamon, lemon, etc. Whether ingested or applied topically, these products only make you or your pet less socially acceptable to other like creatures. Not recommended. It has been theorized that some dogs and cats are better able to groom out fleas with their teeth, so appear to be flea free and escape the ugly monikker “fleabag”.

So we’re talking pesticides to control pests. Thirty years ago we used flea powders, sprays and flea collars, all powered by chemicals in the carbamate and organophosphate family of pesticides. This group of chemicals were not at all selective to fleas – used improperly, they could poison your pet and you. It’s what we had (our “zero”), and we were desperate. The collars worked sometimes on very small pets, since they only covered the neck. Powders would do the job, if you could stand the dust all over your pets’ coat. Sprays were very effective, but required near daily application because as soon as your dog rolled in the grass they were lost in the dew. Forget spraying a cat- one puff and that cat was in the next county. Dips were also effective, though again, none lasted two weeks as dogs roll in the grass…..removing the substance. Most flea dips were toxic to cats, so if applied incorrectly to a cat it would die unless emergency treatment was sought. I spent hours counselling on time consuming methods of flea control that no one thanked me for.

Pest control companies were kept busy spraying yards and houses in an effort to control the flea in the environment. One product, malathion, a mainstay in pest control years ago, to overcome flea resistance had to be sprayed over your entire yard every 10 days to have any efficacy at all according to UC Davis! DIY (do-it-yourself) friendly, it was not. Again, clients were grumpy to receive this news. Today there are a rotating group of pesticides used by pest control companies to fight the flea and prevent resistant strains from developing. Environmental control in the yard is very important; even if your own pet never leaves home, wildlife and roaming pets will almost certainly introduce fleas. Your pet does not live in a bubble!

And then a new generation of medications were discovered. Wonderstuff. Applied topically to the skin of the pets neck or given as a chewey pill, and only ONCE a month, this stuff is amazing! This stuff works! Several products exist for both dogs and cats, all kill fleas within 12 hours of contact with the pet. Reinfesting fleas, flea eggs and larvae in the environment are killed following contact with the treated dog or cat. If you do no environmental control, expect it to take about 90 days to clean up your flea problem. Some of the chemical names we’ll discuss are imidacloprid, spinosad, fipronil and afoxolaner. Ahhh, what’s in a name? Tongue twisters all – the brand names are easier. Curiously, most of these products weren’t developed specifically for your pet.

Spinosad is a pesticide developed to safeguard our food supply, used commercially on fruit and vegetable crops. Spinosad is considered an “organic” insecticide found in a bacteria from sugar cane. Spinosad is considered a natural product, given a Class B designation for pregnant women: No evidence of risk in humans.  It is used on people in medication for human head lice. On dogs and cats it has been found effective primarily against only the flea.

Imidacloprid, another flea fighter available for dogs and cats, is also used on crops and home back yards. Acting as a neurotoxin to insects, when used IN THE YARD, it is a systemic chemical that is taken up by plant roots to its leaves, where sucking/chewing insects will ingest it and die. There has been some question if imidacloprid may adversely affect honeybees (colony collapse disorder), though bees do NOT chew flower or plant parts.

Fipronil is an insecticide that affects the nervous system of insects via pathways that don’t exist in mammals. A broad spectrum insecticide, it is highly toxic to fish and bees. It is widely used for protection of rice crops, field corn, and golf course lawn care. Humans can prevent tick bites by applying it (as directed) to their ankles and wrists. Fipronil can kill rabbits – do NOT use on rabbits for flea control! That said, for years the State of Hawaii has required the veterinarian-only application of Fipronil, specifically, to all dogs and cats 10 days prior to travelling to the state. Fipronil has been widely questioned in honeybee colony collapse disorder.

Afoxolaner is in the newest class of chemical, this one without apparent crop/plant use. It’s sole use is flea AND tick control in dogs. It’s a new isoxazoline parasiticide (I had to read that, why not you?) – its’ claim to fame is that it controls both fleas and ticks via an oral medication for an entire month. Tick control has always been difficult in dogs, and there are many serious tick-borne diseases. The class of isoxazaline drugs may be a breakthrough for livestock that suffer from both ticks and tick borne diseases worldwide.

The flea is here to stay. With considered use of the available products you may be able to control you and your pets’ exposure to fleas and the consequences of flea bites. We aren’t talking eradication. You are not expected to reach Zero.  As for your children, your home and yard, the truth is that flea control on the pet is not deemed of sufficient quantity to add to or create environmental issues at this time. Most of the products we’ve discussed are carried home from Garden Centers and Big Box stores by the quart and gallon weekly as yard and grass treatment for indiscriminate use and disposal by the homeowner. These products all appear much safer for mammals – you, your children, your dogs and cats – than previous options, and every year newer products are developed as we all cope to care for each other and our earth.

Christine B. McFadden, DVM
Valley Animal Hospital, Merced
drmc@mcmenagerie.com

The Flea and Zero Tolerance : Part One

/ Dr. Christine McFadden / Leave a comment

 

Dr Mc Blog

September 7, 2014
One of the more curious things worth pondering is the realization that “zero” is only as low as your ability to measure something, any given parameter, to zero. How much of a given substance is found in your food, how much radioactive activity persists in the ground, how fast a ball flies from the pitchers hand is all measured by a variety of instruments created by man and only as accurate as the instrument currently in use. As technology advances we are able to detect smaller amounts, faster movement, ever tinier invisible particles – and our previously accepted “zero level” decreases accordingly. Fascinating!

Enter the flea, ctenocephalides felis, the common flea of both dogs and cats despite its’ Latin name. The flea has been with us for centuries. A small wing-less creature, it can safely be described as a parasite to most of us, if we accept the definition of parasite to be an organism that exploits or lives off another organism while contributing nothing to its wellbeing. Why do we care what this little insect gets up to in its daily life?

For starters, fleas rarely appear to be doing good deeds. Once an adult flea has pounced upon a dog or cat, it will feast upon its blood (blood meal). In very small, young, or very ill pets enough fleas can together literally suck them dry of their lifeblood, leading to severe flea anemia and death.

While taking that blood meal, the flea actually injects its mouthpart or proboscis into your pets’ flesh which also introduces its saliva. Not only does your pet feel little flea feet crawling all over its skin, it can feel the sting of the bite and worse, develop an allergic reaction to the flea saliva, which will make him itch and break out in a rash. The ultimate reaction is a pet so allergic that they scratch off their hair, their skin, and develop oozing, painful sores called “hot spots”. Medical attention is required to get these under control quickly. Your veterinarian can literally start turning this condition around in hours! Hot spot and other allergy medication does not take days or weeks to work!

Which came first, the flea or the tapeworm egg? In a twist of fate, the tapeworm egg of Diplydium caninum lays on the ground or carpet. A flea larvae MUST eat it for the tapeworm to continue to develop. So the flea larvae eats the tapeworm egg. When the flea bites your pet, the tapeworm larvae is spit out on their coat. Your dog or cat turns to lick at the stinging flea bite and ingests the tapeworm larvae, which is swallowed and grows up inside your pet to become long ribbons of worm segments looped together in the intestine. Often these live segments break apart and are passed in pet feces. You may literally see wiggling flat worms (proglottids to you science types) in pet droppings or even around your pets’ tail. Once dried, they may look like rice or dried sesame seeds. They do not pass daily, so if left untreated don’t be fooled that they’ve naturally gone away if you don’t see them for a week or two. They’re still there.

Ok, so far we’ve discussed fleas on cats and dogs :
anemia, even death;
creepy crawly flea feet running on them;
allergies, hot spots;
tapeworms.

What about people?Some people are bitten by fleas. The bites can be painful, and may cause an allergic skin reaction. The kind of tapeworm, Diplydium caninum, that dogs and cats carry is NOT the tapeworm you hear people can get (they must eat a flea to get this kind of tapeworm – highly uncommon).

But there IS a zoonotic (spread from animals to people) infection fleas CAN transmit: murine typhus, a rickettsial bacteria that may be harbored in feral or pet cats, opposums, and other animals. Murine typhus is an under-discussed suburban vector-borne zoonotic  disease. In the United States California, Texas and Hawaii have had outbreaks. In California, the southern areas of the state are vulnerable. Orange County reported two (2) cases of murine typhus in 2012. When one case was reported in a young girl the county trapped feral cats and opposums near her elementary school searching for the probable source of contagion.  This disease usually responds well to antibiotics and people are easily cured. However, it is uncommon and initial diagnosis can be difficult. The primary recommendation to decrease the risk of murine typhus? 1) Do not feed feral or wild animals near your home. 2) Apply flea prevention/control products to your pets.

Which brings us to the crux of this article. How to prevent fleas on your pets, in your home, on you? Because if you live in Merced County, we provide everything a flea needs to flourish with our long seasons of warm weather and mild winters. We are a flea hospitality haven! Please tune in for Fleas: Part Two : Searching for Ground Zero

Christine B. McFadden, DVM
Valley Animal Hospital, Merced
drmc@mcmenagerie.com