Endocrine Abstracts

A 39-year-old lady presented with chest infection and was found to be hyponatraemic (114 mmol/l) during her third pregnancy. Short synacthen test (SST) revealed inappropriately low ACTH (39 ng/l) with adrenocortical failure (cortical 163, 355, 503 at 0, 30 and 60 min respectively). She was started on replacement hydrocortisone. Adrenal autoantibodies were negative. Other tests showed IGF-1 14.8 (13–50 ηmol/l), growth hormone <0.1 (<10 mU/l), prolactin 677 (<700 mU/l), oestradiol 106, LH 3.7, FSH 6.7. Thyroid function test TSH 2.61 (0.35–5.5 mU/l), Free T3 3.0 (3.0–6.5 ρmol/l), Free T4 9.7 (10.0–23.0 ρmol/l) twelve weeks postpartum. CT of adrenals was normal. MRI pituitary showed normal pituitary gland. She managed to breastfeed postpartum. The first pregnancy (emergency caesarean section, 39 weeks) was complicated by pre-eclampsia, pneumonia and vaginal bleeding requiring dilatation and curettage. In her second pregnancy, she had antenatal and postpartum bleeding but breastfed. A postpartum SST showed partial recovery of the adrenocortical function 313, 525, 612 nmol/l at 0, 30, 60 min respectively. ACTH was 20 ηg/l. Insulin tolerance test revealed partial pituitary failure with maximum cortisol of 449 ηmol/l and maximum growth hormone of 9.1 mU/l at 90 min. TRH stimulation test showed normal TSH response. The gonadotrophin stimulation test was not done as she had regular periods. She is well at present, without hormone replacement and under regular follow-up. She has been advised to take hydrocortisone at times of stress. This case illustrates the dilemmas in interpreting results, especially during pregnancy. While the initial SST indicated adrenocortical failure, the aetiology could not be determined due to pregnancy. Subsequent investigations suggest partial pituitary failure that became apparent at times of stress. Aetiology of pituitary failure remains elusive and is thought to be due to either lymphocytic hypophysitis or Sheehan’s syndrome.