Syndrome of inappropriate antidiuretic hormone secretion as an adverse reaction of ciprofloxacin: a case report and literature review.

Antidiuretic hormone (ADH) is secreted by the posterior pituitary gland. Unsuppressed release of ADH leads to hyponatremia. This condition is referred to as syndrome of inappropriate antidiuretic hormone secretion (SIADH). Hereby, a case report is presented on ciprofloxacin-induced SIADH. A 67-year-old male patient was examined in the emergency room with symptoms of lethargy, headache, lack of attention, and a generally depressed mood lasting for three days. One week prior, empirical antimicrobial therapy involving ciprofloxacin for prostatitis was initiated. Laboratory analysis showed no relevant abnormalities except for hyponatremia (Na = 129 mmol/L). Chronic hyponatremia, thyroid dysfunction, and adrenal dysfunction were ruled out. Serum osmolality was 263 mOsmol/kg, urine osmolality was 206 mOsmol/kg, and urine sodium was 39 mmol/L. Given that all criteria for SIADH were met, ciprofloxacin was discontinued, and fluid restriction was advised. Four days later, the patient's serum sodium concentrations nearly normalized (Na = 135 mmol/L), and all symptoms resolved. The Naranjo Scale yielded a score of 8, supporting the likelihood of a probable adverse reaction to ciprofloxacin. This case is presented to raise awareness among clinicians about the potential of ciprofloxacin to cause even mild hyponatremia.

Inappropriate therapy of euvolemic hyponatremia, the most frequent type of hyponatremia in SARS-CoV-2 infection, is associated with increased mortality in COVID-19 patients.

Introduction: Admission hyponatremia, frequent in patients hospitalized for COVID-19, has been associated with increased mortality. However, although euvolemic hyponatremia secondary to the Syndrome of Inappropriate Antidiuresis (SIAD) is the single most common cause of hyponatremia in community-acquired pneumonia (CAP), a thorough and rigorous assessment of the volemia of hyponatremic COVID-19 subjects has yet to be described. We sought to identify factors contributing to mortality and hospital length-of-stay (LOS) in hospitalized COVID-19 patients admitted with hyponatremia, taking volemia into account. Method: Retrospective study of 247 patients admitted with COVID-19 to a tertiary hospital in Madrid, Spain from March 1st through March 30th, 2020, with a glycemia-corrected serum sodium level (SNa) < 135 mmol/L. Variables were collected at admission, at 2nd-3rd day of hospitalization, and ensuing days when hyponatremia persisted. Admission volemia (based on both physical and analytical parameters), therapy, and its adequacy as a function of volemia, were determined. Results: Age: 68 years [56-81]; 39.9% were female. Median admission SNa was 133 mmol/L [131- 134]. Hyponatremia was mild (SNa 131-134 mmol/L) in 188/247 (76%). Volemia was available in 208/247 patients; 57.2% were euvolemic and the rest (42.8%) hypovolemic. Hyponatremia was left untreated in 154/247 (62.3%) patients. Admission therapy was not concordant with volemia in 43/84 (51.2%). In fact, the majority of treated euvolemic patients received incorrect therapy with isotonic saline (37/41, 90.2%), whereas hypovolemics did not (p=0.001). The latter showed higher mortality rates than those receiving adequate or no therapy (36.7% vs. 19% respectively, p=0.023). The administration of isotonic saline to euvolemic hyponatremic subjects was independently associated with an elevation of in-hospital mortality (Odds Ratio: 3.877, 95%; Confidence Interval: 1.25-12.03). Conclusion: Hyponatremia in COVID-19 is predominantly euvolemic. Isotonic saline infusion therapy in euvolemic hyponatremic COVID-19 patients can lead to an increased mortality rate. Thus, an exhaustive and precise volemic assessment of the hyponatremic patient with CAP, particularly when due to COVID-19, is mandatory before instauration of therapy, even when hyponatremia is mild.

Pearls & Oy-sters: Syndrome of Inappropriate Antidiuretic Hormone Secretion Presenting as Neuromyelitis Optica Spectrum Disorder Flare.

While it was previously believed that neuromyelitis optic spectrum disorder (NMOSD) mostly affected the optic nerves and the spinal cord, it is increasingly recognized that NMOSD can involve any area of the CNS where aquaporin-4 is highly expressed. These other areas can include the hypothalamus and the circumventricular organs that surround the third and fourth ventricles, serving as osmoregulators. The syndrome of inappropriate antidiuretic hormone secretion (SIADH) is one of the most common causes of hyponatremia and has been associated with NMOSD due to these lesions. In this report, we present a case of a patient with known NMOSD, who presented with dizziness, fatigue, and generalized weakness and whose workup revealed hyponatremia in the setting of SIADH and hypothalamic demyelinating lesions. This case illustrates an atypical presentation of NMOSD and the importance of looking for syndromes, such as SIADH. This can guide diagnostic testing, such as getting thin MRI cuts through the hypothalamus and brainstem, as well as advanced management techniques such as immunotherapy.

Prevention and Correction of Dysnatremia After Aneurysmal Subarachnoid Hemorrhage.

BACKGROUND: Dysnatremia occurs commonly in patients with aneurysmal subarachnoid hemorrhage (aSAH). The mechanisms for development of sodium dyshomeostasis are complex, including the cerebral salt-wasting syndrome, the syndrome of inappropriate secretion of antidiuretic hormone, diabetes insipidus. Iatrogenic occurrence of altered sodium levels plays a role, as sodium homeostasis is tightly linked to fluid and volume management. METHODS: Narrative review of the literature. RESULTS: Many studies have aimed to identify factors predictive of the development of dysnatremia, but data on associations between dysnatremia and demographic and clinical variables are variable. Furthermore, although a clear relationship between serum sodium serum concentrations and outcomes has not been established-poor outcomes have been associated with both hyponatremia and hypernatremia in the immediate period following aSAH and set the basis for seeking interventions to correct dysnatremia. While sodium supplementation and mineralocorticoids are frequently administered to prevent or counter natriuresis and hyponatremia, evidence to date is insufficient to gauge the effect of such treatment on outcomes. CONCLUSIONS: In this article, we reviewed available data and provide a practical interpretation of these data as a complement to the newly issued guidelines for management of aSAH. Gaps in knowledge and future directions are discussed.

Intractable hyponatremia secondary to syndrome of inappropriate antidiuresis complicated with empty sella: A case report.

RATIONALE: Hyponatremia is a common electrolyte disorder in elderly critically ill patients, and it may be associated with poor outcomes, higher morbidity, and mortality. Syndrome of inappropriate antidiuresis (SIAD) is one of the main causes of hyponatremia, with an insidious onset that is highly misdiagnosed. Primary empty sella lesions are specific, mostly asymptomatic, and easily overlooked. SIAD combined with empty sella is much rarer in clinic, this article focuses on the diagnosis and management of an elderly patient with intractable hyponatremia secondary to syndrome of inappropriate antidiuresis complicated with empty sella. PATIENT CONCERNS: An 85-year-old male patient with severe pneumonia presented with progressive and intractable hyponatremia. DIAGNOSES: The patient had clinical signs of persistent hyponatremia, low plasma osmolality, elevated urinary sodium excretion, and hyponatremia that worsened with increased intravenous rehydration and was effective with appropriate fluid restriction. The diagnosis of SIAD combined with empty sella was made in combination with the findings of the pituitary and its target gland function. INTERVENTIONS: Numerous screenings were performed to clarify the cause of hyponatremia. His overall condition was poor due to recurrent episodes of hospital-acquired pneumonia. We treated with ventilation support, circulatory support, nutritional support, anti-infection, and continuous correction of electrolyte imbalance. OUTCOMES: His hyponatremia gradually improved through aggressive infection control, appropriate fluid restriction (intake controlled at 1500-2000mL/d), continuous electrolyte correction, supplementation with hypertonic salt solution, and potassium replacement therapy. LESSONS: Electrolyte disorders, especially hyponatremia, are very common in critically ill patients, but the etiology of hyponatremia is challenging to diagnose and treat, and timely attention and proper diagnosis of SIAD and individualized treatment are the significance of this article.

Syndrome of Inappropriate Antidiuresis: From Pathophysiology to Management.

Hyponatremia is the most common electrolyte disorder, affecting more than 15% of patients in the hospital. Syndrome of inappropriate antidiuresis (SIAD) is the most frequent cause of hypotonic hyponatremia, mediated by nonosmotic release of arginine vasopressin (AVP, previously known as antidiuretic hormone), which acts on the renal V2 receptors to promote water retention. There are a variety of underlying causes of SIAD, including malignancy, pulmonary pathology, and central nervous system pathology. In clinical practice, the etiology of hyponatremia is frequently multifactorial and the management approach may need to evolve during treatment of a single episode. It is therefore important to regularly reassess clinical status and biochemistry, while remaining alert to potential underlying etiological factors that may become more apparent during the course of treatment. In the absence of severe symptoms requiring urgent intervention, fluid restriction (FR) is widely endorsed as the first-line treatment for SIAD in current guidelines, but there is considerable controversy regarding second-line therapy in instances where FR is unsuccessful, which occurs in around half of cases. We review the epidemiology, pathophysiology, and differential diagnosis of SIAD, and summarize recent evidence for therapeutic options beyond FR, with a focus on tolvaptan, urea, and sodium-glucose cotransporter 2 inhibitors.

Hyponatraemia caused by transient syndrome of inappropriate antidiuresis to urinary retention.

Hyponatraemia is frequently seen in the emergency department, possibly caused by the syndrome of inappropriate antidiuresis (SIAD). We report three cases in which we believe urinary retention with bladder distention caused hyponatraemia. Laboratory findings fulfilled the criteria for SIAD, for which no cause was found. Possibly pain or sympathetic nerve system activation leads to SIAD. Brisk diuresis occurred after placement of an indwelling urinary catheter with overly correction of sodium for which treatment was necessary. Clinicians should be aware that placement of an indwelling urinary catheter may prompt brisk water diuresis and a tendency to overcorrection.

Intractable hyponatremia complicated by a reset osmostat: a case report.

BACKGROUND: Hyponatremia associated with a low serum osmolality is a common and confounding electrolyte disorder. Correcting hyponatremia is also complicated, especially in the setting of chronic hyponatremia. Here, we provide a rational approach to accurately detecting and safely treating acute on chronic euvolemic hyponatremia in the setting of acute polydipsia with a chronic reset osmostat. CASE PRESENTATION: A 71-year-old hispanic gentleman with chronic hyponatremia presented with hiccups, polydipsia, and a serum sodium concentration of 120 mEq/L associated with diffuse weakness, inattentiveness, and suicidal ideation. Symptomatic euvolemic hyponatremia warranted hypertonic saline treatment in the acute phase and water restriction in the chronic phase. Both interventions resulted in improvement in symptoms and/or the serum sodium concentration, but to a serum sodium level that persistently remained below the normal range. Remarkably, the urine osmolality appropriately fell when the serum sodium concentration fell below 126 mEq/L. Also remarkable was the appropriate increase in urine osmolality when the serum sodium concentration exceeded 126 mEq/L. The preservation of both concentration and dilution, albeit at a lower-than-normal serum osmolality, shows that the osmostat regulating antidiuretic hormone release had been "reset." Both physiologic and pharmacologic resetting of the osmostat are discussed. CONCLUSIONS: Preservation of urinary concentrating and diluting ability at a lower-than-normal serum sodium concentration, especially in the setting of chronic hyponatremia, is diagnostic of a reset osmostat. The presence of a reset osmostat often confounds the treatment of concomitant acute hyponatremia. Early recognition of a reset osmostat avoids the need to normalize serum sodium concentration, expedites hospital discharge, and limits potential harm from overcorrecting acute hyponatremia.

Human herpesvirus 6 (HHV-6) associated permanent hyponatremia in umbilical cord blood transplant recipient.

Long-term neurocognitive deficits after human herpesvirus-6 (HHV-6) infection are common in stem-cell transplant recipients, but SIADH (Syndrome of inappropriate antidiuretic hormone secretion) with persistent hyponatremia is rare. A 51-year-old woman presented with somnolence, hyponatremia (121 mmol/L) and HHV-6 viremia (80,330 copies/ml) on day +22 post umbilical cord blood transplant (UCBT). With waterrestriction, tolvaptan and combination of foscarnet and ganciclovir, patient's hyponatremia and HHV-6 viremia improved. On day +94 UCBT, hyponatremia and HHV-6 viremia recurred. Foscarnet was restarted and continued until day +269 UCBT due to multiple HHV-6 recurrences with persistent hyponatremia. At day +712, patient remains on water-restriction, tolvaptan for continuous hyponatremia from SIADH.

Consensus document on the management of hyponatraemia of the Acqua Group of the Spanish Society of Endocrinology and Nutrition.

INTRODUCTION: Hyponatremia is the most prevalent electrolyte disorder in the outpatient and inpatient settings. Despite this frequency, hyponatremia, including severe hyponatremia, is frequently underestimated and inadequately treated, thus highlighting the need to produce consensus documents and clinical practice guidelines geared towards improving the diagnostic and therapeutic approach to it in a structured fashion. MATERIAL AND METHODS: Members of the Acqua Group of the Spanish Society of Endocrinology and Nutrition (SEEN) met using a networking methodology over a period of 20 months (between October 2019 and August 2021) with the aim of discussing and developing an updated guideline for the management of hyponatraemia. A literature search of the available scientific evidence for each section presented in this document was performed. RESULTS: A document with 8 sections was produced, which sets out to provide updated guidance on the most clinically relevant questions in the management of hyponatraemia. The management of severe hyponatraemia is based on the i.v. administration of a 3% hypertonic solution. For the management of chronic euvolemic hyponatraemia, algorithms for the initiation of treatment with the two pharmacological therapeutic options currently available in Spain are presented: urea and tolvaptan. CONCLUSIONS: This document sets out to simplify the approach to and the treatment of hyponatraemia, making it easier to learn and thus improve the clinical approach to hyponatremia.

Disorders of Salt and Water Balance After Pituitary Surgery.

Transsphenoidal surgery is the first-line treatment for many clinically significant pituitary tumors and sellar lesions. Although complication rates are low when performed at high-volume centers, disorders of salt and water balance are relatively common postoperatively. Both, or either, central diabetes insipidus (recently renamed arginine vasopressin deficiency - AVP-D), caused by a deficiency in production and/or secretion of arginine vasopressin, and hyponatremia, most commonly secondary to the syndrome of inappropriate antidiuresis, may occur. These conditions can extend hospital stay and increase the risk of readmission. This article discusses common presentations of salt and water balance disorders following pituitary surgery, the pathophysiology of these conditions, and their diagnosis and management.

Hyponatremia in the emergency department.

Hyponatremia, defined as a serum sodium <135 mmol/L, is frequently encountered in patients presenting to the emergency department. Symptoms are often unspecific and include a recent history of falls, weakness and vertigo. Common causes of hyponatremia include diuretics, heart failure as well as Syndrome of Inappropriate Antidiuresis (SIAD) and correct diagnosis can be challenging. Emergency treatment of hyponatremia should be guided by presence of symptoms and focus on distinguishing between acute and chronic hyponatremia.

Diagnosis and Management of Hyponatremia: A Review.

Importance: Hyponatremia is the most common electrolyte disorder and it affects approximately 5% of adults and 35% of hospitalized patients. Hyponatremia is defined by a serum sodium level of less than 135 mEq/L and most commonly results from water retention. Even mild hyponatremia is associated with increased hospital stay and mortality. Observations: Symptoms and signs of hyponatremia range from mild and nonspecific (such as weakness or nausea) to severe and life-threatening (such as seizures or coma). Symptom severity depends on the rapidity of development, duration, and severity of hyponatremia. Mild chronic hyponatremia is associated with cognitive impairment, gait disturbances, and increased rates of falls and fractures. In a prospective study, patients with hyponatremia more frequently reported a history of falling compared with people with normal serum sodium levels (23.8% vs 16.4%, respectively; P < .01) and had a higher rate of new fractures over a mean follow-up of 7.4 years (23.3% vs 17.3%; P < .004). Hyponatremia is a secondary cause of osteoporosis. When evaluating patients, clinicians should categorize them according to their fluid volume status (hypovolemic hyponatremia, euvolemic hyponatremia, or hypervolemic hyponatremia). For most patients, the approach to managing hyponatremia should consist of treating the underlying cause. Urea and vaptans can be effective treatments for the syndrome of inappropriate antidiuresis and hyponatremia in patients with heart failure, but have adverse effects (eg, poor palatability and gastric intolerance with urea; and overly rapid correction of hyponatremia and increased thirst with vaptans). Severely symptomatic hyponatremia (with signs of somnolence, obtundation, coma, seizures, or cardiorespiratory distress) is a medical emergency. US and European guidelines recommend treating severely symptomatic hyponatremia with bolus hypertonic saline to reverse hyponatremic encephalopathy by increasing the serum sodium level by 4 mEq/L to 6 mEq/L within 1 to 2 hours but by no more than 10 mEq/L (correction limit) within the first 24 hours. This treatment approach exceeds the correction limit in about 4.5% to 28% of people. Overly rapid correction of chronic hyponatremia may cause osmotic demyelination, a rare but severe neurological condition, which can result in parkinsonism, quadriparesis, or even death. Conclusions and Relevance: Hyponatremia affects approximately 5% of adults and 35% of patients who are hospitalized. Most patients should be managed by treating their underlying disease and according to whether they have hypovolemic, euvolemic, or hypervolemic hyponatremia. Urea and vaptans can be effective in managing the syndrome of inappropriate antidiuresis and hyponatremia in patients with heart failure; hypertonic saline is reserved for patients with severely symptomatic hyponatremia.

Syndrome of inappropriate antidiuretic hormone secretion. / Síndrome de secreción inadecuada de hormona antidiurética.

Hyponatremia is the most frequent electrolytic disorder in hospitalized patients, and the syndrome of inappropriate secretion of antidiuretic hormone (SIADH), the most frequent cause of hiponatremia with clinically normal extracellular volume. It consists of a disorder of the regulation of body water that obeys to different causes, mainly cancer, pulmonary illnesses, disorders of the central nervous system and diverse drugs. As in any hiponatremia it a physiological knowledge of the regulation of body water and sodium is essential as well as the application of precise diagnostic criteria in order to manage the problem with an effective treatment. The available data until the moment show that the clinical diagnosis of SIADH made by professionals is mainly not supported on the established criteria drawn by experts and this lack of accuracy probably hits in the therapeutic result. The basis of the treatment of the SIADH is to correct its cause, water restriction, solutes (sodium chloride) and the use of vaptans in case of failure of the previous measures.

Syndrome of Inappropriate Secretion of Antidiuretic Hormone Associated With Varicella Infection in Children.

A 9-year-old girl with remarkable hyponatremia was diagnosed with SIADH that was likely secondary to varicella. Under appropriate treatment, her serum sodium returned to the normal level. There was no evidence of hyponatremia at a 3-month follow-up. We propose that medical professionals need to consider the existence of that SIADH when treating patients with varicella who present with severe hyponatremia.

Approach to the Patient: Hyponatremia and the Syndrome of Inappropriate Antidiuresis (SIAD).

Hyponatremia is the most common electrolyte disturbance seen in clinical practice, affecting up to 30% of acute hospital admissions, and is associated with significant adverse clinical outcomes. Acute or severe symptomatic hyponatremia carries a high risk of neurological morbidity and mortality. In contrast, chronic hyponatremia is associated with significant morbidity including increased risk of falls, osteoporosis, fractures, gait instability, and cognitive decline; prolonged hospital admissions; and etiology-specific increase in mortality. In this Approach to the Patient, we review and compare the current recommendations, guidelines, and literature for diagnosis and treatment options for both acute and chronic hyponatremia, illustrated by 2 case studies. Particular focus is concentrated on the diagnosis and management of the syndrome of inappropriate antidiuresis. An understanding of the pathophysiology of hyponatremia, along with a synthesis of the duration of hyponatremia, biochemical severity, symptomatology, and blood volume status, forms the structure to guide the appropriate and timely management of hyponatremia. We present 2 illustrative cases that represent common presentations with hyponatremia and discuss the approach to management of these and other causes of hyponatremia.

An observational study on clinico aetiological profile and response to treatment and outcome of patients diagnosed with severe hyponatremia in medicine intensive care unit of a tertiary care centre.

Hyponatremia is defined as serum sodium concentration less than 135meq/l. More severe symptoms are seen when serum sodium falls below 120 meq/l. Hyponatremia in ICU is a very common scenario. Treatment strategy is decided after thorough history taking and clinical examination. Judicious treatment is necessary as rapid correction and delayed correction both can lead to various neurological sequelae. This study was done on critically ill patients who had hyponatremia on the day of admission and clinical and aetiological profile was studied. MATERIAL: An observational study was conducted between March 2020 to July 2021. With in this period of time 210 patients got admitted in medical ICU with serum sodium value less than 120meq/L on the day of admission. Clinico aetiological profile in terms of age, gender, symptoms, co morbidities, response to standard treatment approach, time taken for correction and complications were studied. OBSERVATION: Mean age was 65.5 years. 52.3 % of patients were male. SYMPTOMS: 92.3% had generalised weakness. 89.5% had confusion. 83.8% had nausea and vomiting. 23.8% had body swelling. 26.1% had restlessness. 9% had loss of consciousness and 7.6% had diarrhoea. Comorbidities: Hypertension was present in 41.4% of the patients. Diabetes was present in 24.7%. Hypothyroidism was present in 14.2%. Heart failure, cirrhosis or chronic kidney disease was present in 22.8%. Known pulmonary disease was present in 11.9%. 11.9% patients had history of taking diuretic drugs along with other factors. 1.1% patients were taking other SIADH causing drugs. 94.2% patients had history of low solute intake. In 93.3% Patients hyponatremia was multifactorial. 70.4% patients had hyponatremia due to increased renal excretion of sodium. 82.8% patients were having SIADH. 12.3 % patients had hypokalemia too. DIAGNOSIS: 35.7% patients had intracerebral pathology like CVA, meningitis or SOL. 32.3% had sepsis or underlying infection. 21.9% had dilutional hyponatremia due to underlying CKD/HF/CLD. 7.1% had adrenal insufficiency. 3% patients had other causes of hyponatremia like SIADH causing drugs and malignancy. Mean time to correction of hyponatremia with standard treatment methods was observed to be 3.5 days after admission. COMPLICATIONS: 20.9% patients died in ICU stay. One Patient presenting with Acute liver failure, sepsis developed locked in syndrome. Two Patients developed rest tremor. CONCLUSION: Hyponatremia in ICU in seen in elderly patients more commonly. Hyponatremia remains associated with diseases involving every organ system. Treatment strategies differ with clinical presentation of the patient. Prompt diagnosis and correction at proper pace prevents dreaded complications.

Syndrome of inappropriate secretion of antidiuretic hormone following high dose rate brachytherapy for prostate cancer: a case report.

BACKGROUND: The syndrome of inappropriate secretion of antidiuretic hormone is a disorder characterized by the excess release of antidiuretic hormone and can result in hyponatremia. If managed inappropriately, severe hyponatremia can cause seizures, cerebral edema, and even death. There are various known causes of this inappropriate release of antidiuretic hormone, including malignancy, CNS disorders, and disturbances in the hypothalamic-pituitary-renal axis. However, reports of syndrome of inappropriate secretion of antidiuretic hormone after brachytherapy for prostate cancer are exceedingly rare. CASE PRESENTATION: We report a case of symptomatic hyponatremia secondary to the inappropriate secretion of antidiuretic hormone after prostate high-dose rate brachytherapy under general anesthesia in a patient with adenocarcinoma of the prostate. CONCLUSIONS: In rare instances, inappropriate secretion of antidiuretic hormone can occur after high-dose rate brachytherapy for prostate cancer. The cause is likely multifactorial, involving pain or discomfort ensuing from the surgical procedure, the general anesthesia or intraoperative drugs administered. However, due to the potential severity of the side effects, timely diagnosis is crucial to ensure prompt, and effective management.

[Hyponatraemia in elderly patient - significance, clarification and therapy]. / Hyponatriämie beim alten Patienten ­ Bedeutung, Abklärung und Therapie.

In the general population, the prevalence of mild, usually asymptomatic hyponatremia ranges from 1,7-7,7 %. With increasing age, it rises to 11,6 % in > 75-year-olds. The prevalence is much higher in nursing home residents and hospital patients. Hyponatremia thus represents the most common electrolyte disturbance in the elderly. Despite the existing evidence on the acute as well as chronic effects of hyponatremia, too little attention is paid to it in clinical practice. An algorithm has proven to be useful for the diagnosis of hyponatremia, which enables the cause to be identified in a few simple steps and at the same time leads to the correct therapeutic steps. The goal must be a serum sodium within the normal range. This is the only way to improve the prognosis and functionality of elderly patients. For SIADH, we have a potent substance available in tolvaptan. In order to be able to recognize the danger of overcorrection in time, the adjustment should take place in the inpatient setting.

Ratio Profile: Physiologic Approach to Estimating Appropriate Intravenous Fluid Rate to Manage Hyponatremia in the Syndrome of Inappropriate Antidiuresis.

A hyponatremic patient with the syndrome of inappropriate antidiuresis (SIAD) gets normal saline (NS), and the plasma sodium decreases, paradoxically. To explain, desalination is often invoked: if urine is more concentrated than NS, the fluid's salts are excreted while some water is reabsorbed, exacerbating hyponatremia. But comparing concentrations can be deceiving. They should be converted to quantities because mass balance is key to unlocking the paradox. The [sodium] equation can legitimately be used to track all of the sodium, potassium, and water entering and leaving the body. Each input or output "module" can be counterbalanced by a chosen iv fluid so that the plasma sodium stays stable. This equipoise is expressed in terms of the iv fluid's infusion rate, an easy calculation called the ratio profile. Knowing the infusion rate that maintains steady state, we can prescribe the iv fluid at a faster rate in order to raise the plasma sodium. Rates less than the ratio profile may risk a paradox, which essentially is caused by an iv fluid underdosing. Selecting an iv fluid that is more concentrated than urine is not enough to prevent paradoxes; even 3% saline can be underdosed. Drinking water adds to the ratio profile and is underestimated in its ability to provoke a paradox. In conclusion, the quantitative approach demystifies the paradoxical worsening of hyponatremia in SIAD and offers a prescriptive guide to keep the paradox from happening. The ratio profile method is objective and quickly deployable on rounds, where it may change patient management for the better.