Juvenile primary acquired hypothyroidism in a dog with suspected renal dysplasia

Abstract

A 1‐year 3‐month‐old, female, neutered crossbreed dog presented for investigation of polyuria, polydipsia and azotaemia. Subsequent biochemistry, endocrine testing and abdominal ultrasound identified hypercholesterolaemia, thyroglobulin autoantibody‐positive hypothyroidism, and IRIS stage II non‐hypertensive, non‐proteinuric suspected renal dysplasia, with a concurrent Escherichia coli urinary tract infection. The patient responded well clinically to levothyroxine treatment, with improvement in hypercholesterolaemia, azotaemia and demeanour at home. At follow‐up biochemistry assessment, hyperphosphataemia and hypercalcaemia (total and ionised) were documented, presumed to be driven by renal insufficiency and renal secondary hyperparathyroidism, although this aetiology was not definitively proven. Normalisation of these values was noted following renal diet implementation and addition of phosphate binders. This case highlights acquired primary hypothyroidism with evidence of thyroiditis in a juvenile dog with suspected congenital renal dysplasia.