Primary adrenal failure is a rare condition with an incidence during pregnancy of around 1 case in 12 000 gestations.
A 31 years old primi gravida presented 10 days after giving birth to a healthy child at full term with postural dizziness and severe fatigue. There was no history of excessive blood loss during delivery and her past medical history was unremarkable, but low blood pressure (BP) was reported throughout pregnancy. She mentioned increased body pigmentation over the past year and had a severely pigmented scar on her leg with normal buccal mucosa. BP was 80/50 mmHg with a significant postural drop.
She had low sodium (127 mmol/l) and raised potassium (5.7 mmol/l), associated with dehydration (urea 11.6 mmol/l) and marginally low bicarbonate (21 mmol/l). A synacthen test failed to show a cortisol response (0 and 30 min cortisol <50 nmol/l) and adrenal antibodies were positive with elevated ACTH at 1075 ng/l consistent with primary adrenal failure. Her endocrine investigations showed low IGF1, normal prolactin (548 IU/l) with undetectable oestradiol, FSH and LH. FT4 was 9.4 pmol/l and TSH 1.0 mIU/l. Given her normal prolactin with low IGF1 and FT4, the possibility of associated hypophysitis was considered, although abnormal TFTs may have been indicating sick euthyroid syndrome.
She was immediately treated with hydrocortisone and fludrocortisone was added 2 weeks later resulting in complete resolution of her symptoms. Endocrine testing 2 weeks after initial presentation showed FSH 3.4 IU/l, LH 2.7 IU/l, oestradiol 146 pmol/l, FT4 15 pmol/l, TSH 1.2 mIU/l IGF1 30.2 nmol/l with normal U&Es.
In summary, we present a case of primary adrenal failure with classical symptoms during pregnancy but with the diagnosis made in the postpartum period. The patient had undergone a largely uneventful pregnancy and delivered a healthy child at full term. Her low IGF1 and deranged TFTs at presentation normalised following hydrocortisone replacement therapy.