Endocrine Abstracts

Background: Diagnosis of secondary adrenal insufficiency (SAI) during pregnancy is challenging due to physiological adaptations and progressive increase of cortisol level throughout the pregnancy (1). The 250-mg standard ACTH stimulation test (CST) is recommended for evaluation of adrenal hypofunction in pregnancy however, measurement of serum cortisol (SC) maybe misleading in patients with partial SAI. Furthermore, utility of salivary free cortisol (SaFC) (2) and serum DHEA-sulfate (DHEA-S) measurements has been proposed to improve the accuracy of SAI diagnosis (3).

Case: We report the case of a 33-year old female with history of hypopituitarism secondary to Langerhans cell histiocytosis treated with pituitary irradiation during pre-teen years subsequently leading to Diabetes Insipidus, hypogonadism, and growth hormone deficiency. Prior to pregnancy, her thyroid function and ACTH stimulation tests were normal. She presented at 25 weeks of gestation with complaints of profound fatigue and weight loss. Pregnancy was conceived via in vitro fertilization. Morning serum ACTH and SC were 14.9 pg/ml (7.2-63.3 pg/ml) and 14.95 mg/dl (6.2-19.4 mg/dl), respectively. Serum DHEA-S was 39.5 mg/dl (84.8-378.0 mg/dl). During pregnancy SC levels increase 2-to-3-folds higher than in non-pregnant women and DHEA-S levels usually increase by 2^nd trimester (4). Thus, secondary adrenal insufficiency was suspected. Patient underwent 250-mg ACTH stimulation test with measurements of SC, DHEA-S, and SaFC concentration before, 30, and 60 min after cosyntropin stimulation. SC increased from 14.76 mg/dl to 25.67 mg/dl and 29.69 mg/dl at 30 and 60 min, respectively. Baseline SaFC was 0.128 mg/dl (0.36 +/-0.17 mg/dl) and minimally increased to 0.276 mg/dl and 0.412 mg/dl at 30 and 60 min, respectively. Baseline DHEA-S was 17.1 mg/dl and minimally increased to 19.1 mg/dl and 21 mg/dl at 30 and 60 min, respectively.

Discussion: Previous studies have reported that SaFC and serum DHEA-S measurements can improve the accuracy of SAI diagnosis. Suri et al. proposed that SaFC is superior for assessing adrenal response to ACTH stimulation with cutoff for second trimester being 0.36 +/-0.17 mg/dl at baseline and 2.37+/-0.99 mg/dl after cosyntropin stimulation. Patient in this case report had normal SC peak response to CST however, SaFC levels did not reach expected range after stimulation. Serum DHEA-S is a sensitive indicator of impaired ACTH secretion in patients with SAI (5). Patient in this report had DHEA-S levels that were low throughout the pregnancy. Collectively, the patient′s findings reported here suggest SAI. Initiation of hydrocortisone therapy significantly improve patient′s symptoms.