Copeptin in the differential diagnosis of hypotonic polyuria.

COPEPTIN: Copeptin is secreted in equimolar amount to Arginine Vasopressin (AVP) but can easily be measured with a sandwich immunoassay. Both peptides, copeptin and AVP, show a high correlation. Accordingly, copeptin mirrors the amount of AVP in the circulation and its measurement provides an attractive marker in the differential diagnosis of diabetes insipidus. THE POLYURIA POLYDIPSIA SYNDROME: Diabetes insipidus-either central or nephrogenic-has to be differentiated from primary polydipsia. Differentiation is crucial since wrong treatment can have deleterious consequences. Since many decades, the "gold standard" for differential diagnosis has been the classical water deprivation test, which has several limitations leading to an overall limited diagnostic accuracy. In addition, the test has a long duration of 17 hours and is cumbersome for patients. Clinical signs and symptoms as well as MRI characteristics overlap between patients with diabetes insipidus and primary polydipsia. Direct measurement of AVP upon osmotic stimulation was first shown to overcome these limitations, but failed to enter clinical practice mainly due to technical limitations of the AVP assay. COPEPTIN AS DIAGNOSTIC TOOL IN THE POLYURIA POLYDIPSIA SYNDROME: We have recently shown that copeptin, without prior water deprivation, identifies patients with nephrogenic diabetes insipidus. On the other hand, for the more difficult differentiation between central diabetes insipidus and primary polydipsia, a copeptin level of 4.9 pmol/L stimulated with hypertonic saline infusion differentiates between these two entities with a high diagnostic accuracy, and is superior to the water deprivation test. It is important to note that close sodium monitoring during the hypertonic saline test is a prerequisite. CONCLUSION: Therefore, we propose that copeptin upon hypertonic saline infusion should become the new standard test in the differential diagnosis of diabetes insipidus.

Management of Nocturia and Nocturnal Polyuria.

Nocturnal polyuria (NP), characterized by overproduction of urine at night (greater than 20%-33% of total 24-hour urine volume depending on age), is a major contributing factor in most nocturia cases. Nocturia can be caused by intake, urological, nephrological, hormonal, sleep, and cardiovascular factors. It is therefore important to accurately diagnose both the type of nocturia and the potentially associated medical conditions to determine appropriate treatment. Diagnostic tools, in addition to a thorough history and physical examination, include voiding/bladder diary analyses and questionnaires to diagnose nocturia type (NP, diminished nocturnal/global bladder capacity, global polyuria) and causative factors. Lifestyle modifications are the first intervention implemented for the management of nocturia and NP but, as symptoms progress, such measures may be insufficient, and pharmacotherapy may be initiated. While drugs for benign prostatic hyperplasia and overactive bladder have demonstrated statistically significant reductions in nocturnal voids, patients often fail to achieve a clinically meaningful response. Antidiuretic treatment is warranted for patients with nocturia due to NP because, in many patients, it treats the underlying cause (ie, insufficient secretion of antidiuretic hormone arginine vasopressin) that leads to overproduction of urine at night and has been shown to provide statistically significant reductions in nocturnal voids. Desmopressin, a synthetic analog of arginine vasopressin, is the only antidiuretic treatment indicated specifically for nocturia due to NP. Overall, the pathophysiology of NP is complex and differs from that of other types of nocturia. A multidisciplinary approach is necessary to effectively diagnose and manage this bothersome condition.

Would a new definition and classification of nocturia and nocturnal polyuria improve our management of patients? ICI-RS 2014.

The following is a report of the proceedings of the Nocturia Think Tank sessions of the annual International Consultation on Incontinence-Research Society, which took place September 22-24, 2014 in Bristol, UK. The report is organized into sections pertaining to the main topic of discussion focussing on the question as to whether a new definition and classification of nocturia and nocturnal polyuria would improve the outcome of management in our patients. First, discussions identified theoretical and practical shortcomings of current definitions. Secondly, the utility of several nocturnal polyuria definitions was tested in a real life population in relation to the symptom nocturia, in order to display weaknesses of these definitions. Thirdly, we explored in a clinical population the utility of bladder diary based parameters by asking the question: when nocturia improves, which of these parameters improve most? Based on the above explorations the Think Tank summarized elements of the current definitions that need reconsideration and suggests proposals for further research to reach more practical and more clinically meaningful definitions.

Nocturia Think Tank: focus on nocturnal polyuria: ICI-RS 2011.

The following is a report of the proceedings of the Nocturia Think Tank sessions of the annual International Consultation on Incontinence-Research Society, which took place June 13-15, 2011 in Bristol, UK. The report is organized into sections pertaining to the main topics of discussions having occurred at that meeting, centering on the relationship of nocturnal polyuria (NP) and nocturia but also synthesizing more current evidence advancing our knowledge of the diagnosis and management of nocturia. This article is not meant to be a comprehensive review on the subject of nocturia, a number of which are available in the recent literature. All authors were physically present during, or in a preliminary session just prior to, the meeting in Bristol.

Síndrome poliúrico / Poliuric syndrome

Se sospecha Síndrome Poliúrico (SP) cuando el volumen urinario excede en 2 a 3 veces lo esperado para la edad o cuando a raíz de una deshidratación o restricción hídrica no se produce concentración urinaria adecuada. El volumen y la osmolaridad de los líquidos orgánicos se regulan con gran precisión gracias a la actividad de la hormona antidiurética (HAD), producida en el eje hipotálamo hipofisiario, que maneja la permeabilidad del agua de los túbulos distales y colectores renales. El SP se clasifica en dos grandes grupos: 1) con niveles plasmáticos bajos de HAD (diabetes insípida central DIC o neurogénica y polidipsia primaria) y 2) con niveles plasmáticos normales de HAD (diuresis osmótica y diabetes insípida nefrogénica DIN). El diagnóstico diferencial se hace con la prueba de deprivación acuosa y el tratamiento consiste en reemplazo hormonal con HAD en DIC y en la DIN reducción del aporte calórico proteico con la ingesta libre de agua, más diuréticos tiazídicos y antiinflamatorios. En el presente artículo se hace una revisión actualizada del SP.

Nocturia in adults: etiology and classification.

Nocturia is one of the most bothersome of all urologic symptoms, yet even a rudimentary classification does not exist. We herein propose a classification system of nocturia based on a retrospective study. The records of 200 consecutive patients with nocturia were reviewed. Evaluation included history, micturition diary (including day, night, and 24-hr voided volume), postvoid residual urine (PVR), and videourodynamic study (VUDS). Functional bladder capacity (FBC) was determined to be the largest voided volume in a 24-hr period. The etiology of nocturia was thus classified into one of three groups: nocturnal polyuria ([NP] in which voided urine volume during the hours of sleep exceeds 35% of the 24-hr output), nocturnal detrusor overactivity ([NDO] defined as nocturia attributable to diminished bladder capacity during the hours of sleep), and mixed (NP+NDO); polyuria (24-hr urine output >2,500 cc) was classified separately. There were 129 women and 65 men ranging in age from 17 to 94 years (x=59). Overall 13 (7%) had NP, 111 (57%) NDO, and 70 (36%) had a mixed etiology of their nocturia (both NP and NDO). Forty-five (23%) also had polyuria. These data confirm that the etiology of nocturia is multifactorial and in many instances unrelated to the underlying urologic condition. Nocturnal overproduction of urine is a significant component of nocturia in 43% of patients, most of whom will also have NDO. We believe that treatment should be directed at both conditions.