Endocrine Abstracts

We are presenting a 23-year-old girl with a medical history of juvenile rheumatoid polyarthritis treated with methotrexate, that first addressed to the Endocrinology Department in may 2022 for primary amenorrhoea with poorly developed secondary sexual characters: height 160 cm, weight 48 kg, BMI 18.35 kg/m2, Tanner stages P1, B3. She was treated with oral contraceptives by the gynaecologist in the past without a hormonal assessment. The lab work revealed hypogonadotropic hypogonadism with a positive response to Triptoreline, low androgen hormones, persistent low IGF1, persistent, well-tolerated hypernatremia, and no inflammatory syndrome. A GH deficiency was excluded by glucagon test - GH peaks to 9.16ng/ml. Regarding the persistent hypernatremia with values around 151mmol/l, low copeptin, high normal renin (129.8uUI/ml) and normal aldosterone level, increased serum osmolality and decreased urinary osmolality, with the absence of increased thirst, the suspicion of adipsic diabetes insipidus was raised. It was initiated treatment with desmopressin with the improvement of sodium levels and serum osmolality in the first weeks, following a recurrence of hypernatremia afterwards. The treatment with desmopressin was suspended. Genetic testing was performed for a series of genes for pituitary insufficiency and other defects of steroidogenesis with the identification of a deficiency of 5 alpha-reductase (heterozygous SRD5A1 gene). The magnetic resonance imaging of the hypothalamic-pituitary axis revealed a pituitary microadenoma of 6.7/6/4.5mm. The presence of hypernatremia with low copeptin, persistent low IGF1 with positive stimulation of GH, and the hypothalamic origin of the amenorrhea raise the suspicion of pituitary stalk lesion. We cannot exclude a link between chronic inflammation during childhood because of rheumatoid polyarthritis or the methotrexate treatment and the hypothalamic-pituitary axis involvement.