New onset Addison's disease presenting as prolonged hyperemesis in early pregnancy

A 32-year-old Caucasian was admitted at 14 weeks of gestation with hypotension and weight loss. Family members noted that she appeared "tired" prior to pregnancy Past medical history included primary hypothyroidism treated with thyroxine (100 microg/day). She had a healthy daughter aged 2.5 years who had been born small for gestational age. At about 8 weeks of gestation she started to vomit several times a day. She was treated with antiemetics and intravenous fluids. Following discharge she remained nauseated, weak and lightheaded and lost about 8 kg of weight. After readmission she appeared ill and dehydrated, BMI 16.6 kg/m2, BP 90/60 mmHg supine, 70/50 mmHg upright (with faint-like sensation), normal heart sounds, chest clinically clear, abdomen soft and not tender Investigations revealed severe hyponatraemia (sodium 112 mmol/L), normal potassium level 4.3 mmol/L, normal renal function, TSH 1.31 microIU/mL (reference range (RR): 0.27-4.2), freeT4 1.99 ng/dL (RR: 0.93-1.7), freeT3 3.29 pg/mL (RR: 2.57-4.43), anti-TPO antibodies 467 IU/mL (RR: <34)). She was hyperpigmented, hypotensive and hyponatraemic despite rehydration. Cortisol & ACTH, followed by a 250 microg short Synacthen test were requested and revealed peak cortisol response of 17 nmol/L (RR: above 550 nmol/l) as well as high baseline ACTH (969 pg/mL, RR: 0-46 pg/mL). She was started on hydrocortisone and felt tremendously better A diagnosis of Addisons disease was made (in view of hypothyroidism as a part of Autoimmune Polyglandular Syndrome type II). She was discharged on hydrocortisone and fludrocortisone replacement. Further during her pregnancy there was about two-week foetal growth delay. She, however delivered a healthy female infant at 36 weeks of gestation.

New onset Addison's disease is rare in pregnancy but may present with prolonged vomiting and weight loss. Therefore adrenal failure should be included in the differential diagnosis of hyperemesis gravidarum.