Usefulness of anti-rabphilin-3A antibodies for diagnosing central diabetes insipidus in the third trimester of pregnancy

• Published in: ENDOCRINE JOURNAL Vol. 64; no. 6; pp. 645 - 650
• Main Authors: Sakurai, Kanako, Yamashita, Rika, Niituma, Satsuki, Iwama, Shintaro, Sugimura, Yoshihisa, Arihara, Zenei, Takahashi, Kazuhiro
• Format: Journal Article
• Language: English
• Published: Japan The Japan Endocrine Society 2017; Japan Science and Technology Agency
• Subjects: Adaptor Proteins, Signal Transducing - antagonists & inhibitors; Adult; Anti-rabphilin-3A antibodies; Antibodies; Argipressin; Autoantibodies - analysis; Autoimmune Hypophysitis - diagnostic imaging; Autoimmune Hypophysitis - immunology; Autoimmune Hypophysitis - pathology; Autoimmune Hypophysitis - physiopathology; Biomarkers - blood; Biomarkers - urine; Biopsy; Desmopressin; Diabetes; Diabetes insipidus; Diabetes Insipidus - diagnosis; Diabetes Insipidus, Neurogenic - blood; Diabetes Insipidus, Neurogenic - etiology; Diabetes Insipidus, Neurogenic - urine; Diagnosis; Diagnosis, Differential; Female; Headache; Humans; Hypernatremia; Hypernatremia - etiology; Hypothalamus; Immunoglobulins; Lymphocytic infundibulo-neurohypophysitis; Magnetic Resonance Imaging; Nerve Tissue Proteins - antagonists & inhibitors; NMR; Nuclear magnetic resonance; Organ Size; Pituitary; Pituitary (posterior); Pituitary Gland - diagnostic imaging; Pituitary Gland - pathology; Plasma; Polydipsia; Polyuria; Pregnancy; Pregnancy Complications - diagnostic imaging; Pregnancy Complications - immunology; Pregnancy Complications - pathology; Pregnancy Complications - physiopathology; Pregnancy Trimester, Third; Prenatal Diagnosis; Prostaglandin E2; Rabphilin-3A; Urine; Vasopressin; Vasopressinase; Vesicular Transport Proteins - antagonists & inhibitors; Pregnancy; Lymphocytic infundibulo-neurohypophysitis; Diabetes insipidus; Vasopressinase; Anti-rabphilin-3A antibodies
• ISSN: 0918-8959; 1348-4540
• DOI: 10.1507/endocrj.EJ17-0028

We report a 27-year-old pregnant woman with polyuria, polydipsia and headache in the third trimester of pregnancy. Hypernatremia (153 mEq/L), high plasma osmolality (300 mOsm/kgH2O) and low urinary osmolality (92 mOsm/kgH2O) were observed at the admission to our hospital. Plasma arginine vasopressin (AVP) level was inappropriately low (2.2 pg/mL) compared to the high plasma osmolality. Plasma AVP responses to hypertonic-saline infusion were blunted, and her urine osmolality increased in response to desmopressin. The diagnosis of central diabetes insipidus was made from these results. Magnetic resonance imaging (MRI) of hypothalamic-pituitary region demonstrated a significant enlargement of the pituitary stalk, suggesting the presence of hypophysitis. In addition, serum anti-rabphilin-3A antibodies that have been recently reported as a biomarker of lymphocytic infundibulo-neurohypophysitis, were positive. Diabetes insipidus continued after delivery, suggesting that polyuria was not mainly due to excessive vasopressinase activity or reduced renal sensitivity to AVP by prostaglandin E2 that can cause temporal polyuria during pregnancy. We therefore clinically diagnosed central diabetes insipidus due to lymphocytic infundibulo-neurohypophysitis, without performing invasive transsphenoidal pituitary biopsy. This case suggested the usefulness of anti-rabphilin-3A antibodies for the etiological diagnosis of central diabetes insipidus during pregnancy.