Veterinary Medicine - November 2008 - (Page 612)

Feline osteoarthritis PEER-REVIEWED As in dogs, obesity may contribute to osteoarthritis or the clinical manifestations of osteoarthritis in cats. In a prospective study of 1,457 cats in which body scores were assigned and their health statuses were followed for 4.5 years, an association between excess body weight and lameness was substantiated.1 Compared with optimal-weight cats, heavy cats (5 on a scale of 1 to 6) were 2.9 times as likely to become lame, and obese cats (6 out of 6) were 4.9 times more likely. In this study, the cause of lameness was not conﬁrmed but assumed to be related to osteoarthritis or soft tissue injuries.1 However, in a recent survey of 218 cats, excess weight was not found to be correlated with DJD or osteoarthritis.2 REFERENCES Obesity and osteoarthritis: Is there a link in cats? 1. Scarlett JM, Donoghue S. Associations between body condition and disease in cats. J Am Vet Med Assoc 1998;212(11):1725-1731. 2. Clarke SP, Mellor D, Clements DN, et al. Prevalence of radiographic signs of degenerative joint disease in a hospital population of cats. Vet Rec 2005;157(25):793-799. failure to recognize signs?” As in dogs,3 the radiographic ndings of osteoarthritis do not always correlate well with clinical function. In a radiological study involving cats of all ages, 22% showed evidence of radiographic osteoarthritis, and when patient records were consulted, 33% of these cats also had clinical signs.4 Affected cats were signi cantly older than the control population. These authors also suggested that there may be little correlation between radiographic and clinical ndings or that clinical signs of osteoarthritis in cats are not easily recognized. In a recent study at a university referral hospital, the prevalence of radiographic signs of DJD was 33.9%, and the prevalence of clinical signs was 16.5%, with most affected cats being 10 years of age or older.1 These authors further classi ed their ndings into DJD and osteoarthritis, the second being less common. The elbow joint was the most commonly affected joint in some published studies.1,2,4,5 However, when osteoarthritis (rather than DJD) was speci cally described, the hip joint was most frequently affected.1 Many cats have multiple affected joints, and bilateral involvement is common. PATHOPHYSIOLOGY Osteoarthritis may be categorized as primary or secondary. In primary osteoarthritis, no clear underlying cause is present. With secondary osteoarthritis, an underlying cause can be implied, such as hip dysplasia or previous trauma. In one study, half of the cats with osteoarthritis had an identi able or historical cause, including radiographically identi ed hip dysplasia.1 In another study by the same researchers, 71% of cats had no obvious cause and were classi ed as having primary, or idiopathic, osteoarthritis.5 thritis, or both, together with radiographic evidence of osteoarthritis were recruited for a prospective study.5 Their median age was 11 years. In addition to the cats’ undergoing a clinical examination by a veterinarian, the owners lled out a questionnaire on their cats’ general demeanor, food intake, and lameness. On physical examination, periarticular thickening was a common nding but decreased range of motion was not. Crepitus was not detected, and synovial effusions were seldom present. Cats were treated with oral meloxicam for one month and reevaluated. Most owners thought their cats improved, and the most common clinical sign that improved was the willingness to jump and the height of the jump. Improvement of the stiff gait seen in many cats at the beginning of the study was also signi cant.5 Clinical experience suggests that the behavioral changes that accompany osteoarthritis may be either insidious and easily missed or assumed to be inevitable with advancing age, so the owner does not seek veterinary advice. Because of a pet cat’s lifestyle, lameness or exercise intolerance is not a common owner complaint. Changes in behavior such as decreased grooming, a reluctance to jump up on favorite places, an inability TABLE 1 CLINICAL SIGNS Compared with the radiographic features of feline osteoarthritis, the clinical signs of feline osteoarthritis are not welldocumented. Unlike in dogs, lameness is not common in cats with DJD or osteoarthritis.1,5 Because of cats’ small size and their innate agility, they can often cope with severe orthopedic disease. In addition, bilateral involvement is common, which makes lameness dif cult to detect. It is also notoriously dif cult to elicit pain on clinical examination in some cats. In one clinical study, 28 cats that had historical or clinical evidence of osteoar- Signs of Osteoarthritis Clients Should Watch for in Their Senior Cats • Decreased grooming • Reluctance to jump • Inability to jump as high as before • Urinating or soiling outside the litter box • Increased or decreased sleep • Avoiding human interaction • Hiding • Dislike of being stroked or brushed 612 November 2008 VETERINARY MEDICINE

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Veterinary Medicine - November 2008 Contents Leading Off Editors' Guest Just Ask the Expert Letters Practice Makes Perfect Clinical Exposures Practice Matters Idea Exchange Author Guidelines A Challenging Case: Esophageal Leiomyoma in a Dog Osteoarthritis in Cats: What We Now Know About Recognition and Treatment Product Preview CE Form/Advertiser Index Marketplace/Classifieds Mind Over Miller

Veterinary Medicine - November 2008

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