Flashcards in OnlineMedEd: Nephrology - "Sodium" Deck (11):
Disorders of sodium levels are actually disorders of _______________.
free water movement
Free water is not a measure of volume status. It is a measure of tonicity and the ADH pathway.
Hyponatremia causes water to move _______________.
from the vessels to the interstitium
Hypernatremia causes water to move ______________.
from the interstitium to the vessels
Dustyn recommends breaking hyponatremia and hypernatremia into mild, moderate, and severe states. Review the signs/symptoms of each.
• Mild: asymptomatic (discovered incidentally)
• Moderate: nausea, vomiting, headache
• Severe: coma, seizures
Review the treatments for mild, moderate, and severe hypernatremia.
• Mild: PO H2O
• Moderate: IV NS
• Severe: D5W or 1/2 NS
Review the treatments for mild, moderate, and severe hyponatremia.
• Mild: disease-specific
• Moderate: IVF
• Severe: 3% NaCl
Go through the protocol for determining the subtype of hyponatremia.
First, review the formula for serum osmolarity: 2 x Na + glucose/18 + BUN/2.8. It should be 280.
• If it is isotonic hyponatremia (meaning SOsm ~280), then it is likely pseudohyponatremia, caused by fats and proteins.
• If it is hypertonic hyponatremia (meaning SOsm greater than 280), then it is likely due to hyperglycemic hyponatremia.
• If it is hypotonic hyponatremia (meaning SOsm less than 280), then you need to determine if they are volume-up (e.g., CHF), volume-down (dehydration), or euvolemic (RATS).
List the treatments for the kinds of hypotonic hyponatremia.
• Volume-up: diuresis
• Volume-down: IVF
- Renal tubular acidosis
- Addison's disease: corticosteroid and mineralocorticoid replacement
- Thyroid disease:
- SIADH: volume restriction, gentle diuresis, or demeclocyline
Urine sodium is a surrogate for ______________.
Urine osmolarity is a surrogate for ______________.