ESPE Abstracts (2022) 95 P1-356


1Paediatric Endocrinology Department, Vall d'Hebron University Hospital, Barcelona, Spain; 2Diabetes and Metabolism Research Unit, Endocrinology Department Vall D'Hebron University Hospital, Barcelona, Spain; 3Paediatric Endocrinology Department, Doctor Josep Trueta University Hospital, Girona, Spain; 4Paediatric Endocrinology Department, Mútua Terrassa University Hospital, Terrassa, Spain

Introduction: Differential diagnosis of partial central diabetes insipidus (PCDI) and primary polydipsia (PP) can be challenging. Copeptin is the C-terminal segment of the vasopressin precursor peptide that represents a novel and stable biomarker. Arginine infusion produces a nonosmotic stimulus that causes an increase in copeptin concentrations in healthy subjects. Arginine-stimulated copeptin concentrations have been used to differentiate between patients with central diabetes insipidus (CDI) and PP, setting a copeptin value of 3.8 pmol/l at 60 min as a cut-off point in adults.

Objective: To evaluate the efficacy and safety of the arginine-stimulated test in paediatrics.

Patients and methods: Three patients with polydipsia-polyuria syndrome. After water restriction/desmopressin test, arginine-stimulated test was accomplished. Time points: basal 0',30',60',90',120'. To verify the safety of the test, vital signs and blood tests were monitored.


Patient 1: 5-year-old boy with sudden polydipsia-polyuria syndrome. The 15-hour water restriction test resulted in a maximum urinary osmolality (Osmu) of 601 mOsm/kg that increased up to 845 mOsm/kg after desmopressin. Arginine-copeptin test showed a flat curve with a low copeptin at 60'. Polydipsia-polyuria syndrome clearly improved on desmopressin treatment. MRI showed a small and hypoplastic adenohypophysis with absense of the neurohypophysis signal.

Patient 2: 12-year-old boy with syntelencephaly and severe optochiasmatic atrophy, dysgenetic corpus callosum, without alterations in the hypothalamic-pituitary region. He presented a long-standing polydipsia-polyuria syndrome. The 17-hour water restriction test resulted in a maximum Osmu of 495 mOsm/kg that increased up to 687 mOsm/kg after desmopressin. Arginine-copeptin test showed a flat response but with values above the cut-off point. Desmopressin was started without improvement, therefore it was suspended. Polydipsia-polyuria syndrome improved spontaneously afterwards.

Patient 3: 13-year-old boy with sudden polydipsia-polyuria syndrome. In the basal analysis, he presented plasma osmolality of 303 mOsm/Kgm and water restriction was not performed. Osmu of 98 mOsm/kg increased up to 507 mOsm/kg with desmopressin. Arginine-copeptin test showed a flat curve with low copeptin at 60'. MRI showed an absence of the neurohypophysis and thickening of the pituitary stalk, etiological study pending.

Table1: Arginine-stimulated copeptin test
  Patient 1 Patient 2 Patient 3
  Copeptin (Pmol/L)
Basal 2,4 3,8 1,61
30’ 2,5 4 1,48
60’ 2,3 4,13 1,78
90’ 1,8 3,8 1,98
120’ 2,4   1,47
Diagnosis PCDI no-CDI CDI

Conclusion: The arginine-stimulated copeptin test is a safe procedure and can represent an alternative to the diagnosis of CDI.

Volume 95

60th Annual ESPE (ESPE 2022)

Rome, Italy
15 Sep 2022 - 17 Sep 2022

European Society for Paediatric Endocrinology 

Browse other volumes

Article tools

My recent searches

No recent searches.