Peer-reviewed veterinary case report
Evaluation of Body Weight, Body Condition, and Muscle Condition in Cats with Hyperthyroidism.
- Journal:
- Journal of veterinary internal medicine
- Year:
- 2016
- Authors:
- Peterson, M E et al.
- Affiliation:
- Animal Endocrine Clinic · United States
- Species:
- cat
Plain-English summary
In a study of 462 cats with untreated hyperthyroidism (a condition where the thyroid gland is overactive), researchers looked at how much weight these cats lost and whether it was due to fat loss or muscle wasting. They found that many of these cats were thin or had lost muscle mass. After treatment, most cats gained weight and improved their body condition, but nearly half of them still showed signs of muscle loss. This means that while treatment can help cats regain weight, it doesn't always restore their muscle health completely.
Abstract
BACKGROUND: The contribution of fat loss versus muscle wasting to the loss of body weight seen in hyperthyroid cats is unknown. OBJECTIVES: To investigate body weight, body condition score (BCS), and muscle condition score (MCS) in hyperthyroid cats. ANIMALS: Four hundred sixty-two cats with untreated hyperthyroidism, 117 of which were reevaluated after treatment. METHODS: Prospective cross-sectional and before-after studies. Untreated hyperthyroid cats had body composition evaluated (body weight, BCS, and MCS). A subset of these cats were reevaluated 3-12 months after treatment when euthyroid. RESULTS: Pretreatment body weight (median, 4.36 kg; IQR, 3.5 to 5.2 kg) was lower than premorbid weight (5.45 kg; IQR, 4.6 to 6.4 kg, P < .0001) recorded 1-2 years before diagnosis. 154 (35.3%) cats were thin or emaciated; 357 (77.3%) had loss of muscle mass. Cats showed increases in body weight (median, 4.1 kg to 5.0 kg), BCS (median, 3/5 to 3.5/5), and MCS (2/3 to 3/3) after treatment (P < .001), but mild-to-moderate muscle wasting persisted in 45% of treated cats. CONCLUSIONS AND CLINICAL IMPORTANCE: Most hyperthyroid cats lose body weight but maintain an ideal or overweight BCS, with only a third being underweight. As in human hyperthyroid patients, this weight loss is associated with muscle wasting, which affects >75% of hyperthyroid cats. Successful treatment leads to weight gain and increase of BCS in most cats, but almost half fail to regain normal muscle mass.
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Search related cases →Original publication: https://pubmed.ncbi.nlm.nih.gov/27667652/