Feline Medicine Q&A 05

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A 16-year-old neutered male DSH cat is presented with a 6-month history of severe weight loss. On clinical examination, the cat is noted to be extremely thin, weighing only 2.7 kg, and has bilateral thyroid nodules palpable in the neck. Examine the laboratory results which were obtained using blood collected after an 8- hour fast.

Question	Answer		Article
What is the assessment of these results?	Several abnormalities are present. The cat is hyperthyroid and other laboratory changes (increased liver enzymes, hyperphosphataemia) are likely to be secondary to this disease. The cat is also azotaemic. Creatinine levels are normal but this may be because of reduced muscle mass since the cat is very thin. The reduced USG suggests intrinsic renal disease rather than a prerenal problem, although polydipsia associated with hyperthyroidism could also account for this value.		Link to Article
What are the treatment options for this cat?	The treatment options available for this patient include surgical thyroidectomy, medical management (e.g. carbimazole or methimazole), and radioactive iodine.		Link to Article
Which of these options should be recommended to the owner and why?	There is a concern that this cat has renal failure which is being masked to an extent by its poor muscle mass and concurrent thyroid disease. Hyperthyroidism increases the glomerular filtration rate which can ‘mask’ pre-existing renal disease and it is a worry that treatment of the hyperthyroidism could result in precipitation of overt renal failure. The safest treatment option is, therefore, one of the medical agents, since these are reversible. The cat should be started on a low dose of carbimazole or methimazole and monitored closely (clinically and biochemically). Should any worsening of the azotaemia be seen, treatment can be reduced or stopped. If the cat remains stable, treatments such as thyroidectomy can be considered.		Link to Article