hyponatremia and hyperglycemia: quick hits, quick math

30 Jul


Symptoms (VAGUE, NON-SPECIFIC) include:

  • nausea, vomiting,
  • anorexia,
  • muscle cramping,
  • lethargy,
  • confusion,
  • eventually seizure/coma/death


1st step is to determine the ECF volume status.


Hypertonic hyponatremiamost commonly hyperglycemia, each 100 mg/dL reduces serum Na by 1.7mEq/L

  • quick guesstimation/rule of thumb: add 1 to the sodium level for every 50 mg/dL glucose over 100
    • e.g. glucose 200, sodium 140 -> add 2 to 140 -> corrected Na~=142
    • e.g. glucose 500, sodium 140 -> add 8 to 140 -> corrected Na~=148
  • quick internet cheat: mdcalc’s Sodium Correction for Hyperglycemia



30 seconds of the other stuff….


Isotonic hyponatremia—often referred to as factitious and does not require treatment.


Hypotonic Hyponatermia—Results from intracellular volume expansion with derangement of cellular functions (e.g. SIADH)

  • Six criteria of SIADH 
    • 1. Hypotonic hyponatremia
    • 2. Innappropriately elevated elevated urine osms (>200)
    • 3. elevated urinary Na
    • 4. Clinical Euvolemia
    • 5. Normal adrenal, renal, cardiac, hepatic, and thyroid fxn
    • 6. Correctable with water restriction


Submitted by J. Stanton.


References: uptodate.com; mdcalc.com; picture



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