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My senior cat is losing weight — what now?

Weight loss in an older cat is rarely just ageing. The three commonest causes are chronic kidney disease, hyperthyroidism and dental disease, and all three can be confirmed with blood tests and a mouth exam.

First, how urgent is this?

Go now

  • Weight loss with a complete refusal to eat.
  • Very restless, a fast heart rate, a high body temperature.
  • Open-mouth breathing, or obvious effort to breathe.
  • Sudden collapse, or unable to stand.

Contact your vet today

  • Weight down 5% or more within two weeks.
  • Weight down 5% or more over three months.
  • In cats over 10, chronic kidney disease affects up to 40%, and needs blood tests to confirm.
  • Eating well but still losing weight, and grumpier: over 10, test the thyroid.
  • Hong Kong study: 3.93% of cats aged 10 and over had hyperthyroidism.

Record and observe

  • Stable weight and normal activity, with only age-related muscle loss.
  • Slow loss on a weight-management diet set by the vet.
  • Already under vet care: weigh monthly on the same scale, and bring the record to the next visit.

Before you set off

  • Each weight with its date, on the same scale where possible.
  • How much and what the cat eats, and how often.
  • How much it drinks, and how much urine.
  • Any vomiting, diarrhoea, bad breath or drooling.
  • A list of medicines and supplements, with the time of the last dose.
  • Do not add nutrition gels, human supplements or protein powder on your own.

What your vet may ask and do

  • Ask: when the weight started falling, and how fast.
  • Ask: any change in appetite, drinking, vomiting or stool.
  • Do: weight and a muscle condition score.
  • Do: blood tests (kidney values, thyroid, glucose, protein) and a urine test.
  • Do: blood pressure.
  • Do: a mouth and dental exam, with X-rays.
  • Do: ultrasound of the kidneys, thyroid and gut, then diet and medication once confirmed.

Where to go in Hong Kong

Call the clinic before you drive over, to confirm tonight's arrangements and the location.