Management of Hypokalemia
Approach to Hypokalemia
(1) Definition
• K+ < 3.5 mEq / L
• Mostly due to GI, urinary losses or diuretic therapy.
•
(2) Clinical features
Mild (3.0-3.5): No symptoms usually
Moderate (2.5-3.0): weakness, constipation and arrhythmias
Severe (< 2.5): muscle weakness (lower to upper body), arrhythmias then paralysis (incl. respiratory)
(3) Diagnosis
• Measure K+ levels
• Take ECG if < 3.0 or symptomatic
• ECG findings: T-inversion, ST depression, prominent u wave
• Pseudo-hypokalemia: if there is upstream of IV fluids and other electrolytes are low. No need for further evaluation if symptomatic
• Urinary K+ to identify the source of potassium loss
(5) Management
• Treat the cause if possible and not severe
• 1 mEq / L deficit: 200-400 mEq replacement needed
• If the cause was due to potassium redistribution even low rates of K+ administration can result in hyperkalemia
(6) Monitor K+ Levels
• Mild: monitor three times per week
• Moderate: monitor daily
• Severe: after each 40mEq. Continious ECG monitoring
ECG Changes
Normal
T wave inversion
ST depression
U wave
Consider the cause
(1) Decreased potassium intake: starvation, anorexia, alcoholism
(2) Gastrointestinal losses: diarrhoea, vomiting, intestinal fistulae
(3) Increased renal potassium
loss:
- Drugs: Thiazide diuretics
- Loop diuretics
(4) Transcellular K+ shift:
- Beta-agonists
- Insulin
- Metabolic alkalosis
Mild (3-3.5 mEq/L)
• Treat orally
• Dose: 40-100 mEq per day
• E.g. 2 x 10 mEq tablets three times per day
Deficit: ~ 200 mEq
Moderate (2.5 - 3 mEq/L)
• Treat orally if they can tolerate it
• Dose: 80-100 mEq per day
• E.g. 3 × 10 mEq tablets three times per day
• Alternatively via IV.
Common formulation: 40 mEg in 1,000 mL 0.9% NS
every 6 hours
• Max IV rate (peripheral IV
line): 10 mEq / hr
• Place on a continuous cardiac monitor if infusing at 10 mEg / hr
MADE WITH MEDGRAM.NET
Severe (< 2.5 mEq/L)
• Treat intravenously
• 40 mEq in 1,000 mL 0.9%
NS every 4-6 hours
preferably into a large vein
• Increase infusion rate if life-threatening to up to 20 mEq / L on a peripheral line
• Otherwise in a peripheral line, the max rate is 10 mEq / hr
• On a central line, the max rate is 40 mEq / hr

Hypokalemia: diagnosis and management