Hypokalemia Diagnosis and Management

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Hypokalemia
Hypokalemia is defined as serum potassium below 3.5 mEq/L
Severe hypokalemia can be life-threatening
Potassium is crucial for cell membrane potential
Kidneys and endocrine system regulate total body potassium
Clinical Features
Central Nervous System: Weakness, numbness, cramps, hyporeflexia
Gastrointestinal: Ileus, nausea, vomiting
Renal: Metabolic alkalosis
Cardiovascular: Various arrhythmias and ECG changes
Etiology
Intracellular Shift: Alkalosis, insulin, beta-agonists
Decreased Intake: Low potassium diets, alcohol abuse, fasting
Increased Loss: GI losses, renal losses, excessive sweating
Drug-Induced: Penicillins, lithium, insulin, catecholamines
Other Causes: Leukemia, lymphomas, megaloblastic anemia recovery
Evaluation
Measure serum potassium level
Assess magnesium levels
Perform electrocardiogram (ECG)
Review patient's medications
Hypokalemia Management
Address underlying cause of hypokalemia
Supplement magnesium if deficient
Potassium repletion can be done orally or intravenously
Every 10mEq of KCl increases serum K by approximately 0.1mEq/L
Oral administration is preferred unless severe symptoms or levels below 2.5mEq/L
Oral Potassium Repletion
Oral potassium is inexpensive and rapidly absorbed
KCl tablets are available, with elixir form as an alternative (though less palatable)
K-Dur extended-release tablets may be difficult for some patients to swallow
Increasing dietary potassium intake can supplement or replace tablets for home treatment
Intravenous Potassium Administration
IV potassium must be given in dilute solutions at a slow rate (10mEq/hour)
Generally, IV potassium concentration should not greater than 40mEq/L
Side effects include local tissue burning, phlebitis, and sclerosis
Additional Considerations
Treat hypomagnesemia if present alongside hypokalemia
Re-check ECG after potassium repletion treatment
Hypokalemia in acute or recent myocardial infarction increases risk of ventricular fibrillation
Printable potassium-rich food tables are available for patient education