Although not available at the time of diagnosis of AT, a low dose dexamethasone suppression test was performed recently for evaluation of a new onset of polydipsia and panting; there was complete suppression of serum cortisol (, 27.6 nmol/L) at 4 and 8 h after administration of dexamethasone, making it unlikely that hyperadrenocorticism was the inciting cause of the AT 3 y earlier.