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 abdominal ultrasound identified hypercholesterolaemia, thyroglobulin autoantibody‐positive hypothyroidism, 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, improvement in azotaemia demeanour at home. At follow‐up biochemistry assessment, hyperphosphataemia hypercalcaemia (total ionised) were documented, presumed be driven by insufficiency secondary hyperparathyroidism, although this aetiology was not definitively proven. Normalisation these values noted following diet implementation addition phosphate binders. This case highlights acquired primary hypothyroidism evidence thyroiditis juvenile congenital dysplasia.