Episode 198: Hypernatremia
We discuss the approach to diagnosing and managing hypernatremia in the emergency department.
Hosts:
Abigail Olinde, MD
Brian Gilberti, MD
https://media.blubrry.com/coreem/content.blubrry.com/coreem/Hypernatremia.mp3
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Show Notes
Episode Overview:
* Introduction to Hypernatremia
* Definition and basic concepts
* Clinical presentation and risk factors
* Diagnosis and management strategies
* Special considerations and potential complications
Definition and Pathophysiology:
* Hypernatremia is defined as a serum sodium level over 145 mEq/L.
* It can be acute or chronic, with chronic cases being more common.
* Symptoms range from nausea and vomiting to altered mental status and coma.
Causes of Hypernatremia based on urine studies:
* Urine Osmolality > 700 mosmol/kg
* Causes:
* Extrarenal Water Losses: Dehydration due to sweating, fever, or respiratory losses
* Unreplaced GI Losses: Vomiting, diarrhea
* Unreplaced Insensible Losses: Burns, extensive skin diseases
* Renal Water Losses with Intact AVP Response:
* Diuretic phase of acute kidney injury
* Recovery phase of acute tubular necrosis
* Postobstructive diuresis
* Urine Osmolality 300-600 mosmol/kg
* Causes:
* Osmotic Diuresis: High glucose (diabetes mellitus), mannitol, high urea
* Partial AVP Deficiency: Incomplete central diabetes insipidus
* Partial AVP Resistance: Nephrogenic diabetes insipidus
* Urine Osmolality < 300 mosmol/kg
* Causes:
* Complete AVP Deficiency: Central diabetes insipidus
* Complete AVP Resistance: Nephrogenic diabetes insipidus
* Urine Sodium < 25 mEq/L
* Causes:
* Extrarenal Water Losses with Volume Depletion: Vomiting, diarrhea, burns
* Unreplaced Insensible Losses: Sweating, fever, respiratory losses
* Urine Sodium > 100 mEq/L
* Causes:
* Sodium Overload: Ingestion of salt tablets, hypertonic saline administration
* Salt Poisoning: Deliberate or accidental ingestion of large amounts of salt
* Mixed or Variable Urine Sodium
* Causes:
* Diuretic Use: Loop diuretics, thiazides
* Adrenal Insufficiency: Mineralocorticoid deficiency
* Osmotic Diuresis with Renal Water Losses: High glucose, mannitol
Risk Factors:
* Patients with impaired thirst response or those unable to access water (e.g., altered or ventilated patients) are at higher risk.
* Important to consider underlying conditions affecting thirst mechanisms.
Diagnosis:
* Initial assessment includes history, physical examination, and laboratory tests.