TY - JOUR T1 - Hyponatraemia and hyperpigmentation in primary adrenal insufficiency JF - BMJ Case Reports JO - BMJ Case Reports DO - 10.1136/bcr-2018-227200 VL - 12 IS - 3 SP - e227200 AU - Bernadette Johanna Maria Benner AU - Jelmer Alsma AU - Richard A Feelders Y1 - 2019/03/01 UR - http://casereports.bmj.com/content/12/3/e227200.abstract N2 - Hyponatraemia is a common electrolyte disturbance with multiple causes. We present a case of a 49-year-old Caucasian female with cholangiocarcinoma, who had a hyponatraemia which was initially assumed to be based on a syndrome of inappropriate antidiuretic hormone secretion as paraneoplastic phenomenon. At physical examination, hyperpigmentation was seen and multiple episodes with syncope were reported. Subsequent endocrine assessment with a synthetic adrenocorticotropin hormone (ACTH) stimulation test and measurement of ACTH levels revealed primary adrenal insufficiency also known as Morbus Addison. We started hydrocortisone and fludrocortisone replacement therapy, resulting in resolving of symptoms, hyponatraemia and hyperpigmentation. ER -