We present the case of a 29-year-old G2P1 who was reviewed at 12 weeks gestation. On examination, her BMI was 39.1 kg/m2, her blood pressure was 1280/80 mmHg and she had signs of hypercortisolism including central adiposity, dorsocervical fat pad, and acanthosis nigricans, and violaceous striae. A diagnosis of Cushing’s syndrome was considered. Serial urinary free cortisol measurements were elevated at between 584-842 nmol/L (<150). Early morning cortisol was 735 nmol/L. Midnight salivary cortisol was 2.9 nmol/L (<3.0). MRI pituitary demonstrated a 3.7x4.3x3.8 mm lesion within the pituitary gland's right lobe, suggestive of a pituitary microadenoma.
Metyrapone was commenced at 18 weeks. Labour was induced at 39 weeks and complicated by post-partum haemorrhage. Metyrapone was ceased post-delivery to allow breastfeeding. Inferior petrosal sinus sampling was performed 4 months postpartum confirming elevated right side IPS to peripheral ACTH ratio. Resection of her pituitary adenoma was performed at 5 months post-partum with histopathology confirming Cushing’s disease. Her postoperative course was uncomplicated other than transient diabetes insipidus. Her 48-hour post-resection and ACTH were undetectably low and she was discharged on twice-daily hydrocortisone replacement.
Discussion
Cushing’s disease in pregnancy is rare due to the impairment of gonadotropin signaling in pituitary disease.[i] Changes in circulating levels of corticotrophin-releasing hormone, adrenocorticotrophic hormone, cortisol binding globulin, and CRH binding globulin make a biochemical assessment of cortisol levels in pregnancy challenging. Cushing’s syndrome in pregnancy is high-risk with 60-70% of cases complicated by maternal morbidity, 50% neonatal prematurity, 25-40% neonatal mortality, and 2-4% maternal mortality. Post-pregnancy complications can include poor wound healing, osteoporosis, and heart failure. ii Options for treatment of Cushing’s disease in pregnancy include surgical and medical therapy.