Overview
How is hyponatremia categorized?
What are symptoms of hyponatremia?
What lab tests are used in the evaluation of hyponatremia?
How is urine osmolality used in the diagnosis of hyponatremia?
How is serum osmolality used in the diagnosis of hyponatremia?
How is urinary sodium concentration used in the diagnosis of hyponatremia?
How should IV fluids be used and water restricted in patients with hyponatremia?
What pharmacologic treatment is available for patients with hyponatremia?
What is the pathophysiology of hyponatremia?
At what level of serum osmolality is hyponatremia clinically significant?
How are hyponatremia treatment decisions and recommendations made?
What is the incidence of hyponatremia in the US?
What is the mortality rate for patients with severe hyponatremia?
How does hyponatremia affect the mortality rates of patients with acute myocardial infarction?
How does hyponatremia affect the mortality rates of patients with cirrhosis?
How does hyponatremia affect mortality rates in patients with chronic kidney disease?
How does the prevalence of hyponatremia differ by race, age, and sex?
Presentation
How does hyponatremia typically come to medical attention?
What is exercise-associated hyponatremia (EAH)?
What are symptoms of hyponatremia?
What affects the severity of neurologic symptoms in hyponatremia?
What history should be obtained for patients who present with hyponatremia?
What physical exam is conducted for patients with hyponatremia?
How does hypertonic hyponatremia present?
What causes pseudohyponatremia and how is it avoided?
What causes hyponatremia after transurethral resection of the prostate or hysteroscopy?
What is the treatment for patients with a large osmolal gap due to excess organic solute?
When is hemodialysis used in the treatment of hyponatremia?
What is hypotonic hyponatremia and how is it categorized?
What is the pathophysiology of hypovolemic hypotonic hyponatremia?
What is the pathophysiology of cerebral salt wasting?
Can diuretics cause hypovolemic hyponatremia?
How is hypervolemic hypotonic hyponatremia characterized?
What are the causes of normovolemic (euvolemic) hypotonic hyponatremia?
What medications are associated with syndrome of inappropriate ADH secretion (SIADH)?
Is hyponatremia an adverse effect of desmopressin?
What is the diagnostic criteria for syndrome of inappropriate ADH secretion (SIADH)?
How does reset osmostat cause normovolemic hypotonic hyponatremia?
How does hypothyroidism and adrenal insufficiency cause hyponatremia?
What causes hyponatremia in patients with HIV infection?
What is the most common cause of hyponatremia following surgery?
What dietary factors can induce hyponatremia?
How does hyponatremia affect athletes and marathon runners and how can it be avoided?
How does ecstasy, or MDMA, induce hyponatremia?
What is nephrogenic syndrome of inappropriate antidiuresis (NSIAD) and how is it treated?
What is hyponatremic hypertensive syndrome?
What is the incidence of hyponatremia in different neurologic conditions?
DDX
What should be considered in the differential diagnoses (DDx) of hyponatremia?
What are the differential diagnoses for Hyponatremia?
Workup
What lab tests are used to evaluate hyponatremia?
What does urine osmolality indicate regarding hyponatremia?
What does serum osmolality indicate regarding hyponatremia?
What does urinary sodium concentration indicate regarding hyponatremia?
What ancillary tests are helpful in the evaluation of hyponatremia?
What imaging studies are helpful in the evaluation of hyponatremia?
Treatment
What should be taken into account before making recommendations on the treatment of hyponatremia?
What are the guidelines regarding treatment of symptomatic patients with acute hyponatremia?
What are the guidelines regarding treatment of chronic hyponatremia?
What are the guidelines regarding the treatment of true hypotonic hyponatremia?
What is the first step in treating patients with hyponatremia?
How common is hypotonic hyponatremia and what factors guide its treatment?
What are the treatment options for an asymptomatic hyponatremic patient?
What are the treatment recommendations for normovolemic (euvolemic), asymptomatic hyponatremia?
What are the treatment recommendations for patients with overtly symptomatic hyponatremia?
How is symptomatic acute hyponatremia treated differently than chronic hyponatremia?
What is the goal of treatment for acutely symptomatic hyponatremia?
What is the goal of treatment for chronic, severe symptomatic hyponatremia?
Which pharmacologic agents can be used to treat hyponatremia?
What is the role of aquaretics in the treatment of hyponatremia?
What diet recommendations are suggested for patients with hyponatremia?
Guidelines
What are the European clinical practice guidelines on the diagnosis and treatment of hyponatremia?
What are the treatment guidelines for hyponatremia?
Medications
What treatments are used in the management of hyponatremia
Which medications in the drug class Antibiotics are used in the treatment of Hyponatremia?
Which medications in the drug class Diuretics are used in the treatment of Hyponatremia?
Follow-up
What monitoring and measuring is required for hyponatremic patients during and after treatment?
What are the clinical manifestations of hyponatremia?
How does hyponatremia affect premenopausal women?
What neurologic impairment can stem from rapid correction of hyponatremia?
What is the clinical course of patients with osmotic demyelination syndrome?
What is the prognosis of hyponatremia?
What are the mortality rates associated with hyponatremia?
What patient education is necessary for patients with hyponatremia?
Tables
United States Guidelines |
European Guidelines |
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Symptomatic Acute Hyponatremia < 24-48 hours |
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Urgent correction goal to aim to prevent brain herniation |
Increase serum Na+ by 4-6 mmol/L |
Increase serum Na+ by 5 mmol/L |
Treatment based on symptoms |
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Severe symptoms |
Bolus 100 mL of 3% NaCl over 10 minutes x 3 as needed |
Bolus 150 mL of 3% NaCl over 20 minutes, 2- 3 times as needed, checking Na every 20 minutes (First-hour management, regardless of acute or chronic condition) |
Moderate symptoms with low risk of herniation |
Continuous infusion of 3% NaCl at 0.5-2 mL/kg/h |
Bolus 150 mL 3% NaCl over 20 minutes, x 1 to prevent further decrease in Na |
Limit not to exceed |
None in true acute hyponatremia |
None in true acute hyponatremia |
Chronic Hyponatremia > 48 hours |
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Correction rate |
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Goal in symptomatic patients using hypertonic saline |
4-8 mmol/L/d if low risk for ODS 4-6 mmol/L/d if high risk of ODS For patients with severe symptoms, the first day’s increase can be accomplished during first 6 h |
Avoid > 10 mmol/L in the first 24 h And > 8 mmol/l during every 24 h thereafter |
Limit to avoid potential harm in asymptomatic patients |
10-12 mmol/L/d, but max 18 mmol in 48 h if at low risk for ODS 8 mmol/L/d if at high risk of ODS |
10 mmol/L in the first 24 h and 8 mmol/l during every 24 h thereafter |
Managing Overcorrection of Chronic Hyponatremia |
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Baseline serum Na+ ≥ 120 mmol/L: Intervention probably unnecessary |
Start once above mentioned limits are exceeded |
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Baseline serum Na+ < 120 mmol/L: Replace water orally or as D5W at 3 mL/kg/h with or without desmopressin (2-4 µg every 8 h parenterally) Withhold any vasopressin receptor antagonists (vaptans) used Consider dexamethasone, 4 mg every 6 hr for 24 hr following excessive correction |
Consult an expert to discuss infusion containing electrolyte-free water (10 mL/kg) over 1 h with or without 2 µg desmopressin IV every 8 h |
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Other Treatment Options |
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Hypovolemic hyponatremia |
Isotonic saline |
Isotonic saline or balanced solution at 0.5-1.0 mL/kg/h |
Euvolemic hyponatremia (SIADH) |
Fluid restriction of 500 mL/d below the 24-h urine volume (first-line treatment) Urea, vaptan, or demeclocycline (second-line treatment) |
Fluid restriction (first-line) Urea or loop diuretics + oral NaCl (second-line) Do not recommend vaptans Recommend against lithium or demeclocycline |
Hypervolemic hyponatremia |
Fluid restriction, loop diuretic Vaptans |
Fluid restriction Recommend against vaptans and demeclocycine |
