Electrolytes

Hyponatremia (Corey Slovis)

• Acute (less than 48 hours), Chronic (more than 48hours) emedicine
• Chronic: usually diuretic use with low salt diet in CHF; most are stable and needs no treatment or water restriction for mild cases
• causes of acute severe symptomatic: water intoxication (eg marathoners who drink water but without sodium; ecstacy users who drink a lot of water) and SIADH
• Morbidity/Death if untreated: Brainstem herniation and CPM

When to treat?

1. Coma, Seizure, Focal findings (CSF) on a previously well patient (not poor premorbid)
2. below 120 mEq/L usually 100-110 mEq/L

*seizures may appear at level below 115 mEq/L with 50% mortality (source: Geriatric Emergency Medicine by Meldon)

What to treat? Rate?

• Hypertonic Saline Solution (3%)
• 100mls (2ml/kg) x 10 minutes, if still seizing 100 mls x 50 minutes

Target increase?

• 3-5 mEq/L

Max?

• 0.5 meq/hr or less OR 10-12 meQ/day (24x0.5)

If too rapid a correction?

• Give D5W

CPM (Central Pontine Myelinolysis)

• demyelinating disease of pons and CNS
• flaccid paralysis, dysarthria, hypotension
• alcoholics, malnourished, severely ill
• due to rapid correction of hyponatremia
• may be seen 1-2 days after correction

Nice to know (Sodium levels)

• 0.9% NaCl = Normal Saline Solution: 154 mEq/L of Na and Cl

Hypertonic (due to hypertonicity, may result to phlebitis, tissue necrosis, should be via central venous catheter)

• 3% NaCl: 468 mEq/L
• 5% NaCl: 856 mEq/L

Hypotonic

• 0.45% NaCl (usually with D5): 77 mEq/L of Na and Cl, 50 g/L glucose
• 0.22% NaCl: 39 mEq/L of Na and Cl, and always contains 5% dextrose for osmolality reasons