Hypokalemia: Difference between revisions
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*Serum potassium level is diagnostic | *Serum potassium level is diagnostic | ||
**Normal = 3.5-5meq/L | **Normal = 3.5-5meq/L | ||
Revision as of 21:19, 23 July 2016
Background
Clinical Features
- CNS
- Weakness
- Cramps
- Hyporeflexia
- GI
- Ileus
- Renal
- CV
- PACs/PVCs
- Bradycardia or atrial/junctional tachycardia
- AV block
- Ventricular tachycardia, Ventricular fibrillation
Differential Diagnosis
Shift
- Alkalosis (each 0.10 rise in pH causes 0.5 decrease)
- Insulin
- B-agonist
Decreased intake
- Special diets or those low in potassium
Increased loss
- GI
- Vomiting, diarrhea, fistula
- Renal
- Diuretics
- Hyperaldo
- Exercise
- Hypercalcemia
- Hypomagnesemia
Drugs
- Penicillins
- Lithium
- L-dopa
- Theophyline
Evaluation
- Serum potassium level is diagnostic
- Normal = 3.5-5meq/L
- Severe hypokalemia = <2.5meq/L
- Suggestive ECG findings:
Management
- Potassium repletion (PO or IV)
- Every 10mEq KCl → serum K ↑ ~0.1mEq/L
- PO preferred (if symptomatic or level is <2.5, both oral and IV should be given)
- Oral potassium
- Inexpensive and rapidly absorbed
- KCl tablet (elixir form available but has poor taste)
- K-Dur (extended release tablet) is large and may be difficult to swallow
- Intravenous potassium
- Must be given in dilute solutions at slow rate (10meq/hour) to minimize side effects and cardiac toxicity
- Generally should not give more than 40mEq via IV
- Side effects: Local tissue burning, phelbitis, sclerosis
- Also treat Hypomagnesemia if present
Disposition
- Based on underlying cause