Multiple electrolyte disturbances as the presenting feature of multiple endocrine neoplasia type 1 (MEN-1).

In young patients presenting with primary hyperparathyroidism, clinicians should be alerted to the possibility of other underlying endocrinopathies. In patients with multiple endocrine neoplasia type 1 (MEN-1) and ectopic adrenocorticotrophic hormone syndrome (EAS), clinicians should be alerted to the possibility of this originating from a neoplasm above or below the diaphragm. Although relatively rare compared with sporadic cases, thymic carcinoids secondary to MEN-1 may also be associated with EAS. Electrolyte derangement, in particular hypokalaemia and hypercalcaemia, can precipitate mild nephrogenic diabetes insipidus.