Diabetes insipidus in children. I. Arginine-vasopressin determination in plasma during short dehydration test

Paediatric perspectives in the diagnosis of polyuria-polydipsia syndrome

The elucidation of the underlying cause of polyuria-polydipsia syndrome (PPS) is a challenging-especially in the differentiation of partial defects of arginine vasopressin (AVP) secretion or action from primary polydipsia. The water deprivation test has been utilized for many decades, and its application in the paediatric population has been applied using parameters predominantly established in adult cohorts. In more recent times, the development of automated commercial assays for copeptin, a surrogate marker for AVP, has represented a significant advancement in the diagnostic approach to PPS. Measurement of copeptin concentrations has major advantages and has essentially superseded measurement of AVP in diagnostic protocols for PPS. Additionally, stimulated-copeptin protocols utilizing hypertonic saline infusion, arginine, and glucagon have been investigated, and are promising. However, further studies are required in the population-incorporating the differences in physiological regulation of water homeostasis, and safety requirements-before there is widespread adoption into clinical practice.

Plasmatic arginine vasopressin levels in total and partial diabetes insipidus

Plasma arginine vasopressin (AVP) was measured in 24 patients with polyuria exceeding 3.5 l/day diagnosed as severe or partial diabetes insipidus according to the dehydration test. All patients with severe diabetes insipidus diagnosed by the dehydration test had very low or undetectable basal AVP values and always subnormal plasma osmolality. Patients with partial diabetes insipidus diagnosed by the dehydration test had a wide range of AVP and osmolality values. The stimulation test performed on these patients was able to differentiate patients with primary polydipsia from patients with partial diabetes insipidus. The measurement of basal plasma AVP is capable of diagnosing all patients with severe diabetes insipidus; when we combine the stimulation test with the measurement of AVP, we can differentiate partial diabetes insipidus from other forms of polyuria.

Endocrine aspects and tumoral markers in intracranial germinoma: an attempt to delineate the diagnostic procedure in 14 patients

This work outlines the endocrine abnormalities associated with intracranial germinomas (14 patients before treatment). Diabetes insipidus of various intensity was present in all cases. Adipsia is often present as well. In six patients, the first neuroradiologic examination after the onset of DI was normal. Growth hormone secretion was deficient in 11 of 13 patients. Abnormalities of TSH response to TRH were present in nine of ten (four insufficient and five exaggerated responses to TRH). Anterior pituitary dysfunction could not be predicted by the tumor site as determined by radiologic criteria. Tumoral markers have also been studied. Elevated plasma tumoral markers were found in four patients of 11 studied. Tumoral germinoma cells were present in CSF in five patients of ten, in one of them before radiologic confirmation. Pertinent endocrine evaluation and search for tumoral markers was of great value in systematic follow-up of patients with central diabetes insipidus, and could lead to early diagnosis and treatment of the tumor.