Severe hypoglycemia and reduction of insulin requirement in a girl with insulin-dependent diabetes mellitus: first sign of a craniopharyngioma.

A girl with a history of insulin-dependent diabetes mellitus since 5.5 years, and Hashimoto's thyroiditis since 12 years, developed episodes of severe hypoglycemia from the age of 12 years. This was associated with falling insulin requirements, from 0.78 U/kg/day at 11 years to 0.34 U/kg/day at 16 years. At 16 years she was found to have GH, gonadotropin, ACTH, and probably also TSH deficiency with hyperprolactinemia. MRI scan revealed a cystic intrasellar craniopharyngioma with moderate suprasellar extension. In spite of cortisol replacement at 17 years, insulin requirement fell further to 0.25 U/kg/day at 18 years. In this girl, decreasing insulin requirements represented an early manifestation of combined growth hormone and cortisol deficiency.