Reset osmostat syndrome

Reset osmostat syndrome (ROS) is characterized by a change of normal plasma osmolality threshold (decrease or increase), which leads to chronic dysnatremia (hypo- or hypernatremia). We have described a clinical case of ROS and chronic hyponatremia in a patient with chordoid glioma of the III ventricle. It is known that the patient had previously been diagnosed with hyponatremia (131-134 mmol/l). She has not hypothyroidism and hypocorticism. There is normal filtration function of the kidneys was (CKD-EPI 91...

Hyponatremia is the most prevalent electrolyte imbalance encountered among hospitalized patients, athletes, the elderly, patients with chronic ailments, postoperative patients, and a few asymptomatic individuals. Clinical manifestations of hyponatremia can be diverse, with characteristic neurological symptoms. Depending on in-depth medical history, physical examination (including volume status assessment), laboratory investigation, and drug history, patients can be classified broadly as undergoing hypervolemic, euvolemic, or hypovolemic hyponatremia...

The application of pathophysiologic tenets has created significant changes in our approach to hyponatremia and hyponatremia-related conditions. This new approach incorporated the determination of fractional excretion (FE) of urate before and after the correction of hyponatremia and the response to isotonic saline infusion to differentiate the syndrome of inappropriate secretion of antidiuretic hormone (SIADH) from renal salt wasting (RSW). FEurate simplified the identification of the different causes of hyponatremia, especially the diagnosis of a reset osmostat and Addison's disease...

Euvolemic hyponatremia is frequently encountered in hospitalized patients and the syndrome of inappropriate antidiuretic hormone secretion (SIADH) is the most common cause in most patients. SIADH diagnosis is confirmed by decreased serum osmolality, inappropriately elevated urine osmolality (>100 mosmol/L), and elevated urine sodium (Na) levels. Patients should be screened for thiazide use and adrenal or thyroid dysfunction should be ruled out before making a diagnosis of SIADH. Clinical mimics of SIADH like cerebral salt wasting and reset osmostat should be considered in some patients...

Reset osmostat (RO) is classified as type C among the four subtypes of the syndrome of inappropriate secretion of antidiuretic hormone based on antidiuretic hormone (ADH) secretion. It is characterized by a lower plasma osmolality threshold for ADH excretion when plasma sodium concentration is reduced. We report the case of a boy with RO and a giant arachnoid cyst (AC). The patient had been suspected of having AC since the fetal period, and a giant AC in the prepontine cistern was confirmed by brain magnetic resonance imaging 7 days after birth...

Our understanding of hyponatremic conditions has undergone major alterations. There is a tendency to treat all patients with hyponatremia because of common subtle symptoms that include unsteady gait that lead to increased falls and bone fractures and can progress to mental confusion, irritability, seizures, coma and even death. We describe a new approach that is superior to the ineffectual volume approach. Determination of fractional excretion (FE) of urate has simplified the diagnosis of a reset osmostat, Addison's disease, edematous causes such as congestive heart failure, cirrhosis and nephrosis, volume depletion from extrarenal salt losses with normal renal tubular function and the difficult task of differentiating the syndrome of inappropriate secretion of antidiuretic hormone (SIADH) from cerebral/renal salt wasting (C/RSW)...

Hyponatremia is the most common electrolyte disorder in hospitalized patients. The syndrome of inappropriate antidiuresis (SIAD) is one of the leading causes of hyponatremia. Although not widely known, SIAD has a vast spectrum of etiologies and differential diagnoses and has been classically divided into four types (A, B, C, D). Frequently, when we use the term SIAD in clinical practice, it refers to subtype A, the so-called classic SIAD. The purpose of reporting this case is to make the clinicians aware of a specific subtype of SIAD, type C, an underdiagnosed entity called osmostat reset (OR)...

The consumption of new selective serotonin reuptake inhibitors (SSRIs) is raising dramatically especially in European countries. It contributes to occurrence of clinically important drug side effects. One of which can be hyponatremia. We present two case reports of 85-year-old and 84-year-old women who developed hyponatremia after escitalopram administration. We hypothesize that in both cases hyponatremia was connected with antidepressants administration. However, due to multiple comorbidities and polypharmacy it is often impossible to establish the exact mechanism of hyponatremia...

Hyponatremia, especially if acute and severe, can be a life-threatening condition. Several conditions can trigger hyponatremia. In this review, we will discuss two conditions that can determine euvolemic hyponatremia: the cerebral/renal salt wasting (CRSW) syndrome and the syndrome of inappropriate secretion of antidiuretic hormone (SIADH), including the two subtypes: reset osmostat (RO) and nephrogenic syndrome of inappropriate antidiuresis (NSIAD) and their differential diagnoses. Despite the passage of over 70 years since its first description, to date, the true etiopathogenesis of CRSW syndrome, a rare cause of hypovolemic/euvolemic hyponatremia, is almost unknown...

OBJECTIVES: Clinical and laboratory data of reset osmostat (RO) and cerebral/renal salt wasting (C/RSW) mimic syndrome of inappropriate antidiuretic hormone (SIADH) and can pose diagnostic challenges because of significant overlapping between clinical and laboratory findings. Failure to correctly diagnose hyponatremia may result in increased mortality risk, longer hospital stay, and is cost-effective. We aim to illustrate clinical and laboratory similarities and difference among patients with hyponatremic disorders and discuss the diagnostic value of factional uprate excretion (FEurate) to differentiate SIADH from RO and C/RSW...

PURPOSE OF REVIEW: The topic of hyponatremia is in a state of flux. We review a new approach to diagnosis that is superior to previous methods. It simplifies identifying the causes of hyponatremia, the most important issue being the differentiation of the syndrome of inappropriate secretion of antidiuretic hormone (SIADH) from cerebral/renal salt wasting (RSW). We also report on the high prevalence of RSW without cerebral disease in the general wards of the hospital. RECENT FINDINGS: We applied our new approach to hyponatremia by utilizing sound pathophysiologic criteria in 62 hyponatremic patients...

Our evaluation of hyponatremic patients is in a state of confusion because the assessment of the volume status of the patient and determinations of urine sodium concentrations (UNa) >30-40 mEq/L have dominated our approach despite documented evidence of many shortcomings. Central to this confusion is our inability to differentiate cerebral/renal salt wasting (C/RSW) from the syndrome of inappropriate secretion of antidiuretic hormone (SIADH), syndromes with diametrically opposing therapeutic goals. The recent proposal to treat most or all hyponatremic patients makes differentiation even more important and reports of C/RSW occurring without cerebral disease leads to a clinically important proposal to change cerebral to renal salt wasting (RSW)...

BACKGROUND: The approach to hyponatremia is in a state of flux, especially in differentiating syndrome of inappropriate antidiuretic hormone secretion (SIADH) from cerebral-renal salt wasting (RSW) because of diametrically opposite therapeutic goals. Considering RSW can occur without cerebral disease, we determined the prevalence of RSW in the general hospital wards. METHODS: To differentiate SIADH from RSW, we used an algorithm based on fractional excretion (FE) of urate and nonresponse to saline infusions in SIADH as compared to excretion of dilute urines and prompt increase in serum sodium in RSW...

Hyponatremia, serum sodium < 135 mEq/L, is the most common electrolyte abnormality and is in a state of flux. Hyponatremic patients are symptomatic and should be treated but our inability to consistently determine the causes of hyponatremia has hampered the delivery of appropriate therapy. This is especially applicable to differentiating syndrome of inappropriate antidiuresis (SIAD) from cerebral salt wasting (CSW) or more appropriately, renal salt wasting (RSW), because of divergent therapeutic goals, to water-restrict in SIAD and administer salt and water in RSW...

BACKGROUND: There is controversy over the prevalence of the syndrome of inappropriate antidiuretic hormone secretion (SIADH) and cerebral or renal salt wasting (RSW), 2 syndromes with identical common clinical and laboratory parameters but different therapies. The traditional approach to the hyponatremic patient relies on volume assessment, but there are limitations to this method. METHODS: We used an algorithm that relies on fractional excretion of urate (FEurate) to evaluate patients with hyponatremia and present 4 illustrative cases...

Hyponatremia is the most common electrolyte disorder in hospitalized patients associated with increased morbidity and mortality. On the other hand, inappropriate treatment of hyponatremia (under- or mainly overtreatment) may also lead to devastating consequences. The appropriate diagnosis of the causative factor is of paramount importance for the proper management and avoidance of treatment pitfalls. Herein, we describe the most common pitfalls in the evaluation of the hyponatremic patient, such as failure to exclude pseudohyponatremia or hypertonic hyponatremia (related to glucose, mannitol or glycine), to properly assess urine sodium concentration and other laboratory findings, to diagnose other causes of hyponatremia (cerebral salt wasting, reset osmostat, nephrogenic syndrome of inappropriate antidiuresis, prolonged strenuous exercise, drugs) as well as inability to measure urine osmolality or delineate the diagnosis and cause of the syndrome of inappropriate antidiuretic hormone secretion...

Hyponatremia is the most common electrolyte abnormality. Its diagnostic and therapeutic approaches are in a state of flux. It is evident that hyponatremic patients are symptomatic with a potential for serious consequences at sodium levels that were once considered trivial. The recommendation to treat virtually all hyponatremics exposes the need to resolve the diagnostic and therapeutic dilemma of deciding whether to water restrict a patient with the syndrome of inappropriate antidiuretic hormone secretion (SIADH) or administer salt and water to a renal salt waster...

Neonatal hyponatraemia is common, and related to significant morbidity and mortality. We report a case of a preterm newborn (gestational age of 36 weeks) with hyponatraemia, and with a prenatal diagnosis of cleft lip and palate, with a normal fetal karyotype. On the seventh day of life, a biochemical evaluation for jaundice and mild signs of dehydration showed hyponatraemia of 124 mmol/L. Investigation showed normal adrenal and thyroid functions, plasma hyposmolality (258 mOsm/kg); high urinary sodium (73 mmol/L) and high urinary osmolality (165 mOsm/kg)...

The reset osmostat syndrome, a form of inappropriate antidiuretic hormone secretion (SIADH), occurs when the threshold for antidiuretic hormone secretion is moved downward. There is evidence to suggest a "reset osmostat phenomenon" in normal pregnancies, whereby the average plasma-osmolality is decreased by 5-10 mOsm/kg. We present a case of a non-physiologic reset osmostat in a pregnant patient, thought to be caused by large intracranial arteriovenous malformations and intraventricular hemorrhage. The presence of a reset osmostat should be suspected in any patient with apparent SIADH who has mild hyponatremia that is stable over many days despite variations in sodium and water intake...

BACKGROUND: Reset osmostat (RO) occurs in 36% of patients with syndrome of inappropriate antidiuretic hormone secretion (SIADH) and is not often considered when evaluating hyponatremic patients. Patients with RO are not usually treated, but recent awareness that symptoms are associated with mild hyponatremia creates a therapeutic dilemma. We encountered patients with hyponatremia, hypouricemia and high urine sodium concentration (UNa), who had normal fractional excretion (FE) of urate and excreted dilute urines that were consistent with RO...