2016 SPRING: Heart Murmurs | Pearls from the ACVIM Forum | 3D Printing Assists Surgical Decisions | Oral Hygiene | Adderall Toxicity | Meet Robert Schick, DVM, DACVD | Continuing Education
What’s that Sound? Approaching Heart Murmurs in Dogs and Cats
Danielle Laughlin, DVM, DACVIM-Cardiology
Unexpectedly finding a heart murmur during a routine wellness examination is common. Determining what, if any, additional diagnostics are warranted can be difficult, and many owners will want to know possible causes before they decide to visit a cardiologist. Recommendations vary on a case-by-case basis, but generally considering the patient’s signalment, clinical signs and the client’s goals can help recognize which cases are most likely to benefit from advanced diagnostics including echocardiography.
Systolic murmur in a puppy
Benign or “innocent” murmurs are not uncommon in puppies. These murmurs are generally soft (I-II/VI), systolic, loudest at the left base and typically resolve by 4-6 months of age. Importantly, these murmurs are not associated with clinical signs. It is reasonable in an otherwise healthy puppy with no familial history of heart disease and a quiet left basilar murmur to recommend waiting and rechecking when they are older. Offering echocardiography at the time of initially hearing the murmur is a good idea as some owners will want to be more proactive and pursue imaging sooner. For purebred puppies about to be sold or those with heart disease documented in their lineage, echocardiography is reasonable when the murmur is first heard.
Puppies with murmurs and clinical signs of heart disease including lethargy, weakness, collapse or breathing difficulties should be referred for an echocardiogram. Additionally, puppies with arrhythmias, abnormal heart sounds, right-sided or apical murmurs, moderate to loud murmurs especially associated with a palpable precordial thrill (grade III-VI), and those with continuous murmurs should all receive recommendation for echocardiography as soon as possible.
Systolic murmur in an adult small breed dog
The most common murmur in a small breed middle-aged to older dog is chronic degenerative valvular disease causing mitral and/or tricuspid regurgitation. This classically leads to a systolic left (mitral) and/or right (tricuspid) apical murmur. With moderate to severe degenerative valvular disease the murmurs are typically at least moderate (grade III/VI or above). Since the risk of congestive heart failure and the associated clinical signs of tachypnea at rest, coughing and dyspnea correlates with cardiac (and specifically left atrial) size, thoracic radiographs are a reasonable initial diagnostic in an adult small breed dog with a systolic apical murmur. Generally, if the heart size is normal (VHS < 10.5 in most breeds) and the patient is asymptomatic, monitoring with thoracic radiographs every 12 months is recommended. With radiographic cardiomegaly, rechecking every 6 months is indicated or sooner if clinical signs develop. An initial echocardiogram to confirm the underlying disease type is reasonable even when the heart size is normal but should certainly be considered when there is radiographic evidence of cardiomegaly. Benefits of echocardiography not apparent on radiographs include assessing for pulmonary hypertension, systolic function and additional flow abnormalities. Small breed adult dogs with murmurs that are atypical in location or accompanied by arrhythmias or clinical signs should always be offered echocardiography and consultation with a specialist.
Systolic murmur in an adult large breed dog
Large breed dogs can also be affected by degenerative mitral and tricuspid valve disease, but dilated cardiomyopathy is considerably more common in these breeds than in small breeds and can be difficult to diagnose without echocardiography. Large breed dogs with dilated cardiomyopathy can have no audible murmur or a very low-grade murmur despite having severe cardiac disease. For this reason, any large dog with clinical signs suggestive of cardiac disease, radiographic evidence of cardiomegaly, or any cardiac murmur should be offered echocardiography.
Diastolic murmurs in dogs
Diastolic murmurs are uncommon in small animals and auscultation of these murmurs always warrants referral to a cardiologist for additional imaging. These are typically associated with severe aortic regurgitation such as that seen with bacterial endocarditis. Other aortic valve abnormalities or, in theory, severe pulmonic insufficiency with pulmonary hypertension and mitral/tricuspid stenosis could also cause diastolic murmurs.
Benign murmurs are very common in cats and are often related to relatively rapid blood flow through the right ventricle (called dynamic right ventricular outflow tract obstruction). These murmurs are systolic in timing and can be heard on either the right or left parasternal areas. They typically are mild to moderate in intensity (grade I-III/VI) and may vary with heart rate or be intermittently audible. Unfortunately, the only way to differentiate a benign feline murmur from a pathologic murmur associated with cardiomyopathy or valvular dysplasia is echocardiography. Radiographs can offer support for underlying heart disease if there is clear cardiomegaly (VHS >8, “valentine” shape) though normal thoracic radiographs do not rule out the possibility of heart disease. It is reasonable, therefore, to offer owners of feline patients referral for echocardiography at the time a murmur is ausculted. This recommendation is especially important if the patient requires general anesthesia for surgery or dental cleaning. Cats with loud murmurs (> grade IV/VI), arrhythmias, or clinical signs should always be offered echocardiography. Cats can also have cardiomyopathy without an audible murmur so some patients, especially those with a family history of cardiac disease or those intended for breeding, may require an echocardiogram despite not having a murmur.
A recent summary released in the Journal of Small Animal Practice (E.Coté et al. Incidentally detected heart murmurs in dogs and cats: executive summary 2015) is available online and provides more information and frequently asked questions regarding incidental murmurs in small animal patients. Please contact our cardiologists, Dr. Laughlin and Dr. Pogue, at BluePearl-GVS with any questions about your patients.
Pearls from the ACVIM Forum 2015
Can you trust the urine SG (USG) in dogs with glucosuria?
A recent study evaluated the effect of adding increasing concentrations of glucose to urine samples with varying starting USGs. Predictably they found that the lower the starting nonglucosuric USG, the greater the effect adding glucose had on the subsequent USG. Furthermore, the higher the concentration of glucose added to the urine sample, the greater the change in the subsequent USG. However, the addition of even higher concentrations of glucose to urine samples with low USG failed to cause clinically significant changes in the final USG. Researchers concluded that the presence of glucosuria did not interfere with the assessment of renal concentrating ability. (Behrend et al)
Are all antiemetic medications the same?
Well that depends on your goal. Gastric antral motility (contractions per minute) was measured before, during and hourly after the feeding of a meal in normal dogs given metoclopramide, maropitant, dolasetron or saline 1 hour prior to feeding. Researchers found that all three medications increased gastric motility prior to feeding and then intermittently during hourly measurements performed for 7 hours after feeding. Only metoclopramide increased motility at all time measurements. If the goal is only to inhibit nausea then all three medications can be effective. However, if increasing gastric emptying is also the goal, then metoclopramide may be your drug of choice. (Bogard et al)
So how do the new anti-seizure medications add up?
Phenobarbital still appears to be one of the most effective medications for treating seizures in dogs. Alternative medications continue to be evaluated with the goal of avoiding the short-term side effect of sedation and long-term side effect of potential liver disease. A review of records of dogs receiving zonisamide (40), levetiracetum (16) or phenobarbital (65) as first line therapy for control of seizures found that phenobarbital was more likely to be associated with adverse effects but was also most effective as monotherapy to control seizures. Dogs receiving zonisamide or levetiracetum were ultimately more likely to require additional therapy to reduce seizure frequency. (Waldron et al) In another study evaluating zonisamide alone, approximately 75% of 53 dogs demonstrated a 50% reduction in seizure frequency. (Nomura et al)
3D Printing Used to Correct Angular Limb Deformity
Alan Cross, DVM, DACVS
Cinderella is an 8-month-old kitten who was adopted by her owner when she was two months old. Since adoption, she has had an abnormal hindlimb gait. She was unable to place her left rear foot on the ground and walked with a twisted spine. Palpation of the limb revealed a femoral deformity and abnormal stifle motion.
|Routine radiographs were obtained of her leg to better assess the deformity and plan surgical correction. Her deformity, secondary to a chronic femoral fracture malunion and distal physeal growth disturbance, was complex, and we were unable to adequately plan the correction based on radiographs alone.|
|Cinderella was briefly anesthetized and a CT scan of her femur was performed. It was rendered in 3D which allowed better appreciation of the deformity. The image file was then sent to a 3D printer and a life-sized 3D model of Cinderella’s leg was printed.|
|Having a life-sized, exact representation of her deformed femur is invaluable for angular deformity correction. In essence, we could practice the surgery the night before, determining exactly where osteotomies needed to be placed to achieve correct joint alignment. Cinderella had a medial 90 degree closing wedge osteotomy performed on her femur the next day. She recovered well from the procedure and began bearing weight normally on her leg for the first time since she was a kitten.|
The Importance of Veterinary Oral Hygiene
Susan Yohn, DVM, MS, DABVP-Canine/Feline, DACVIM
Dental disease is commonly diagnosed in dogs and cats. It is estimated that 80% of adult dogs and 70% of adult cats have some form of oral disease. Dental problems, especially when halitosis is present, are among the top reasons for pet owners to visit the veterinarian. Plaque and calculus formation with associated gingivitis are the most common clinical conditions diagnosed by veterinarians in dogs and cats of all ages. Why is the incidence of dental disease so high in our companion animals? Pets living longer may be one of the reasons that dental disease is prevalent. It may also be related to lack of owner education and compliance with at-home and professional veterinary dental preventative care.
As veterinary professionals, we are responsible for promoting dental prophylaxis procedures to keep our patients healthy, as well as educating our clients on the importance of preventative oral care for their pets.
Why is dog and cat oral health so important?
Owners often will not seek veterinary care for periodontal disease until they notice pain when touching the pet’s face; reluctance to eat or abnormal chewing; drooling; bleeding; food being dropped from the mouth; and/or halitosis. But, periodontal disease can be seen as early as 6 months of age, and by 3 years of age, most dogs and cats have evidence of periodontal disease. Dental issues in young dogs and cats can include retained deciduous teeth, supernumerary teeth, malocclusion and misalignment. These conditions, left unmanaged, can lead to overcrowding of the teeth and trauma to soft tissues and gums contributing to periodontal disease in the older pet.
Periodontal disease progresses if effective dental prophylactic therapy is not pursued. Advanced periodontal disease can cause the pet oral and systemic health problems including loose, broken or infected teeth; dental abscesses affecting tooth alveolus; mandible or maxilla osteomyelitis; and possible systemic infections or negative impact on organ function. Additionally, veterinary literature shows a correlation between the severity of periodontal disease in dogs and histopathologic changes in myocardial, renal and hepatic tissue. Oral pathologies cause pain for the pet with effects on appetite, behavior changes (irritability, socialization) and general morbidity.
How can we educate the pet owner about home health care?
Pet oral hygiene is accomplished through a combination of veterinary therapy and care at home. Owners should be educated about signs of dental problems, significance of periodontal disease, and importance of preventative care. Owner education starts in the exam room. It is important for the veterinarian to assess both the pet and owner when considering home dental care. Is the owner interested, committed and physically able to perform home oral care? Will the pet’s temperament allow home oral care? Prescribed home dental care will not work if the owner or pet are not compliant.
Showing the client changes in the pet’s mouth during the oral exam (tartar or plaque accumulation, evidence of gingivitis, juvenile dental malformations) will help reinforce the need for preventative care. It is also important to show the owner how to train the pet to tolerate touching of the mouth and gums.
Prescribing dental home hygiene without showing the client how to proceed will increase noncompliance, so the veterinary team should demonstrate oral cleansing techniques to the owner. The veterinary team can demonstrate on one side of the pet’s mouth with a toothbrush, finger brush, swab or gauze. Observing the owner brushing the other side of the mouth provides an opportunity to offer brushing tips and suggestions.
Dental wash solutions or a dental diet may be a better oral care option for owners and pets that cannot use brushing tools. Not all commercial products that say “veterinarian recommended” are effective as dental aids. Clients can visit the Veterinary Oral Health Council website (www.vohc.org) for a list of independently evaluated dental products receiving their seal of approval as effective dental care aids.
How can we educate the pet owner about professional veterinary dental care?
With severe periodontal disease, professional prophylaxis may be necessary before prescribing home dental care. It’s important to educate the owner on the reasons for professional dental cleaning and the procedures used:
- Routine dental cleaning for pets with periodontal disease can prevent infections, pain and systemic illness.
- Professional dental cleaning is done under anesthesia to allow the veterinarian to examine the mouth, stage disease, determine the need for extractions, clean above and below the gum, and determine an appropriate home dental care plan.
- Dental X-rays, important to evaluate tooth roots and bone, must be done with anesthetic restraint.
Physical examination and lab profiling should be standard of care, especially for older pets to minimize risk of anesthesia. Fluid diuresis should also be considered depending on each pet’s medical condition. Explanation of the pet’s predental evaluation and dental procedure will help reassure the client about the need for anesthesia and allow the practice of the highest quality medicine.
How can we educate the pet owner about appropriate follow-up?
Dentistry should be part of a pet’s overall preventative health care plan starting with the first puppy or kitten visit. Evaluating dental health at each annual exam helps reinforce the importance of early preventative care and provides the opportunity to remind owners that periodontal disease progresses at the same rate in dogs and cats as in people.
In older pets, a dental recheck should be recommended 3 to 6 months following professional cleaning or after starting a home dental plan. For pets with other medical conditions, such as cardiac disease or renal insufficiency, frequent dental evaluation is appropriate. These evaluations give the veterinary team an opportunity to evaluate the effectiveness of the pet owner’s home dental care and to provide encouragement to continue.
By helping improve the overall health of each pet, veterinary dental care provides an important client and pet service as well as providing professional and financial rewards to the veterinary professional.
Adderal (Dextroamphetamine) Toxicity
Adderal is an amphetamine that causes release of endogenous catecholamines leading to central nervous system and cardiovascular stimulation. Examples of other amphetamines include Ritalin® (methylphenidate), methamphetamine, Dexedrine® (dextroamphetamine) and Vyvanse® (lisdexamfetamine). Amphetamine toxicity in dogs has become common due to increased availability with use for treatment of attention deficit disorder.
Clinical Signs and Physical Examination
Clinical signs from toxicity develop rapidly and are typically seen < 4 hours after exposure (up to 8 hours with extended release). Adderal toxicity will cause restlessness, hyperactivity, panting, shaking, seizures, ataxia, head bobbing, circling, weakness and collapse. With severe cases sudden death is possible. On physical examination we can also diagnosis tachypnea, bilateral mydriasis, hyperthermia, cardiac arrhythmias and tachycardia. Clinical signs can last between 12 and 48 hours and tend to be longer with extended release formulas.
If no clinical signs are present with recent exposure emesis induction should be performed and activated charcoal administered. Once clinical signs develop agitation should be managed with acepromazine. Diazepam should be avoided as it can worsen dysphoria and central nervous system signs. Serotonin syndrome can be treated with cyproheptadine (oral or rectal). With severe tachycardia propranolol can be considered if the blood pressure is normal. If severe tachycardia and hypertension are present esmolol should be considered. Hospitalization with supportive care including fluid diuresis, monitoring vitals, minimizing sensory stimuli and thermoregulation is commonly needed.
Many patients with minimal clinical signs or aggressive care will make a full recovery. A poor prognosis is present with severe hyperthermia, head bobbing, severe tachycardia and seizures. Complications can include disseminated intravascular coagulation and rhabdomylosis leading to renal failure.
Meet our dermatologist…
Robert Schick, DVM, DACVD
If someone wrote a biography about Robert Schick, an apropos title might be “Itching to Fly.” The veterinary dermatologist is as comfortable flying his plane as he is diagnosing pemphigus foliaceus. Many also know him for his passion for the sports teams of his alma mater, the University of Florida, although in Georgia that enthusiasm isn’t always shared. Dr. Schick has practiced veterinary dermatology since 1986, having come to Atlanta after completing his residency at the University of Pennsylvania. Get to know Dr. Schick…
Robert Schick, DVM, DACVD
What’s cutting edge in dermatology?
In chronic otitis cases we’re able to utilize our onsite CT and MRI as well as our video otoscopy to make more precise diagnoses and prognoses. This allows us to formulate more accurate treatment plans. If surgery is required, our surgeons are available on site for further treatment options.
What’s the best piece of advice you were ever given, and who gave it to you?
My father was the first board-certified radiologist in Clearwater, Florida. As a child I was able to accompany him to the hospital and sit alongside him as he read his patients’ radiographs. I already knew that I wanted to be a veterinarian, but this is when I learned that I wanted to be a specialist. To me, knowing a lot about a finite area was fascinating. I also learned at an early age from him to always concentrate on being the best doctor possible and to treat the patient/owner like they were a family member (preferably one you like!).
Was there a college professor or vet school course that changed your life?
Valerie Fadok, dermatologist at the University of Florida, was my first contact in veterinary dermatology. As an undergraduate student I took my dog to the vet school for skin problems, and she was my clinician. Over time she became my mentor and close friend. She taught me to take the approach of looking broadly at the whole patient problem list before narrowing the focus.
Outside of veterinary medicine, at what do you consider yourself to be an expert?
I’ve been a private pilot for more than 21 years and have more than 3400 hours of flight time. I still enjoy it today as much as the first day I soloed, as it’s a great thrill to be up in the air, looking down at the terrain below.
What was your first job?
When I was 14, I worked at Robby’s Pancake House (in Clearwater) as a busboy. Through hard work, I was able to move up to being a cook. I worked there for three years and then took a job as a horse trainer/professional rider.
What is something people might be surprised to know about you?
I’ve been SCUBA diving since I was 16, but in the last five years I’ve become fascinated with underwater photography.
If you knew then what you know now, what would you do differently?
I would’ve joined the military, hopefully as a pilot. This is one of the reasons why I enjoy being involved in the Wounded Warrior Airlift program. It’s a true honor to help transport a disabled veteran or the veteran’s family member in their time of need.
Is there a case that stretched you as a clinician and taught you something a meaningful about yourself and your practice?
There was a case of hepatocutaneous syndrome that we diagnosed and treated for about 18 months. This was an example of a team-based approach that involved our nutritionist, the criticalists and dermatology for a comprehensive treatment plan. We were thrilled that we were able to give this dog a good quality of life for longer than what is typical with this disease.
Continuing Education: Come learn with us!
BluePearl is strongly committed to the veterinary community. One of the ways we demonstrate this commitment is through our continuing education program, which is subsidized in part by our Partners in Education. Please check our online calendar regularly for the most current information about courses, dates and locations.