Background
Isolated ACTH deficiency is a rare pituitary disorder.
Most case reports discuss uncomplicated outcomes with glucocorticoid replacement doses in pregnancy and postpartum period.
Case details:
28 year old lady, G1P0 was referred to obstetric medicine clinic at 8 weeks gestation. She was diagnosed with isolated ACTH deficiency 7 years ago. She was on replacement doses of cortisone 25mg morning and 12.5mg evening. This was an unplanned pregnancy.
During the first trimester, she had up titrated her cortisone doses (50mg mane/25mg evening) due to morning sickness. This was weaned to pre-pregnancy doses at around 17 weeks of gestation.
At 23 weeks gestation, she presented with pedal edema and was noted to have hypercalcemia. Her corrected calcium was 2.87mmol/L (peak 3.0 mmol/L) with suppressed PTH and normal 25-OH vitamin D levels.
The possible causes of hypercalcemia included pregnancy, significant dairy intake and steroid under-replacement.
She developed gestational hypertension 1 week later and was commenced on methyldopa.
After careful consideration, the cortisone doses were increased to 37.5mg mane and 25mg evening at 26 weeks gestation. The hypercalcemia resolved by 28 weeks gestation.
However, she developed mild pre-eclampsia (PET) at 32 weeks. She remained under close observation. MFM growth scan showed normal fetal growth.
Her risk factors for PET included nulliparity, gestational hypertension, hypercalcemia and supraphysiological doses of glucocorticoids.
She developed severe PET at 34 weeks requiring emergency caesarean section. Her baby weighed 2.3kg at birth and was well. Her cortisone doses have been reduced and she has not had any further complications till now.
Summary:
Isolated ACTH deficiency clinically manifests as secondary adrenal insufficiency (AI) 1. Glucocorticoid replacement requires careful attention to enhance maternal outcomes and avoid adrenal crisis2. The side-effects of treatment include hypertension, gestational diabetes and exacerbation of PET3.
Our case highlights the potential complications that can be faced in a patient with secondary AI and raises an area of discussion regarding optimal management.