Table 1.

Results of investigations at presentation and review. At presentation, there was evidence of inappropriately low urine osmolality combined with high serum osmolality accompanying hypernatraemia, which was suggestive of diabetes insipidus. Also, hypercalcaemia and inappropriately ‘normal’ PTH levels combined with urine calcium levels were inconsistent with familial hypocalciuric hypercalcaemia or calcium ‘set point’ anomalies; hypercalcaemia normalised on Li dose reduction. Finally, thyroid antibody negative for hyperthyroidism subsided spontaneously.