Osteoarthritis in cats: Clinical signs
QUICK LINKSPrevalence and pathophysiology
Compared with the radiographic features of feline osteoarthritis, the clinical signs of feline osteoarthritis are not well-documented. 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 difficult to detect. It is also notoriously difficult to elicit pain on clinical examination in some cats.
In one clinical study, 28 cats that had historical or clinical evidence of osteoarthritis, 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 filled out a questionnaire on their cats' general demeanor, food intake, and lameness. On physical examination, periarticular thickening was a common finding 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 significant.5
Inactivity, which may result from chronic joint pain, is much more difficult to determine in cats than in dogs since cats naturally sleep a lot and are often solitary. In many cases, the owners are not home all day to monitor their cats' activity levels and may not know whether they have changed. Activity monitors attached to cat collars and harnesses have been used to monitor daily movement in cats,6,7 including in cats with osteoarthritis during treatment with oral meloxicam or placebo.7 In that study, the activity counts increased with five days of nonsteroidal anti-inflammatory drug (NSAID) treatment, suggesting alleviation of musculoskeletal discomfort.
It is common for owners and veterinarians not to realize how affected a cat was until they see dramatic improvements after treatment, emphasizing that analgesic trials may sometimes be the only way to confirm that pain was present.
Editors' note: Dr. Robertson has received financial support from Boehringer-Ingelheim Vetmedica to conduct workshops for Boehringer-Ingelheim veterinarians, write one review article, and speak at veterinary continuing education meetings.