Emerging diseases and solutions: Innovations in feline practice - DVM
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Emerging diseases and solutions: Innovations in feline practice

DVM Best Practices

We are now able to treat heart disease with more success than in the past. We used to rely on digoxin, but its side effects and lack of efficacy in cats made treatment of heart failure disappointing. The mainstay of my treatment protocol for congestive heart failure in cats is benazepril (2.5 mg/cat once a day for cats weighing up to 5 kg; cats weighing 5 kg or more are given 5 mg/cat once a day). Not only is it more effective than digoxin in correcting heart failure, but it has been shown to cause thinning of the left ventricular wall in cats with early hypertrophic cardiomyopathy.4 It recently became available as a generic product, so its cost is reasonable. Spironolactone, an older drug previously used as a diuretic, is making a resurgence because it helps treat heart failure when used in subdiuretic doses (6.25 mg b.i.d.). Atenolol, a betablocker, is indicated when premature ventricular contractions or tachycardia is present. It should be given at 6.25 mg b.i.d. Furosemide (1.1 to 2.2 mg/kg b.i.d.) and topical nitroglycerin round out the list of cardiac drugs I typically use.

Diagnosing and treating heartworm disease Once thought to be a rare anomaly, feline heartworm infection is diagnosed with increasing frequency in most parts of the United States. Heartworm disease is an important cause of heart disease in cats. However, diagnosis and treatment are plagued with problems. Because the worm burden is so low in most affected cats, serum antigen tests often yield false negative results. Serum antibody tests lack the specificity to be reliable. Therefore, the typical diagnostic workup for feline heartworm disease includes serum antigen and antibody tests, thoracic radiographs, and echocardiograms.

Figure 4. Echocardiogram of the cat in Figure 3 showing greatly thickened left ventricular walls associated with hypertrophic cardiomyopathy. Because the wall thickening is principally directed inward, severe disease was present even though the cat had a normal cardiac silhouette on radiography. Radiographs lack the sensitivity of echocar-diography in diagnosing this disease.
Treatment is based on supportive care of the cat, usually with corticosteroids, until the adult worms die. The only approved drug for treating adult heartworms in dogs, melarsomine, is toxic in cats. Therefore, the best way to deal with feline heartworm disease is prevention. A chewable preventive product is available, but cats' finicky appetites often lead to noncompliance. Applying selamectin (Revolution—Pfizer Animal Health) monthly is a very practical way to prevent heartworm infection and control most external and internal parasites.

Advances in ultrasonography Ultrasonography is a skill that many practitioners think is beyond their reach. Fewer than 10% of primary-care, small-animal hospitals own an ultrasound machine. However, like other skills practitioners possess, it can be mastered with determination. The major ultrasound companies offer hands on, off-site training courses to help practitioners become proficient with this technology. Several hours of personal instruction are needed to develop skills and build confidence. Most practitioners become quite proficient in routine scanning procedures after a few courses, as long as they practice with their own machines.

Most ultrasound units allow images to be saved. Images can then be e-mailed to veterinary consultants for interpretation. Using the specialists' feedback, practitioners can review the images on the ultrasound machine's hard drive to improve their interpretation abilities. Most practitioners who use telemedicine services do so regularly at first and then decrease their use as they become more proficient.

Conclusion Feline medicine has never been more rewarding. Once mistakenly considered "small dogs,"cats have become a major part of the pet population and smallanimal practice. Improved healthcare, an indoor lifestyle, and more dedicated owners allow many cats to live 20 years or longer.They are the sole focus of my practice, but they also comprise a large portion of most small-animal practices.With increased understanding of feline diseases and new diagnostic and therapeutic products,we're able to give new meaning to the saying, "cats have nine lives."

References 1. Brown S.A.: Evaluation of chronic renal disease: A staged approach. Comp. Cont. Ed. 21(8):752-763; 1999.

2. DiBartola, S.P.; Rutgers, H.C.: Diseases of the kidneys. The Cat: Diseases and Clinical Management, 2nd Ed. (R.G. Sherding, ed.) Churchill Livingstone, London, England, 1994;pp 1711-1767.


Source: DVM Best Practices,
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