Acute Hypokalemia Management - Hospitalist

Algorithm Steps

1. ▶

   Start

   Hypokalemia Detected

   K+ <3.5 mEq/L

   1. ●

      Action

      Severity Classification

      Determines urgency

      • MILD: K+ 3.0-3.4 mEq/L
      • MODERATE: K+ 2.5-2.9 mEq/L
      • SEVERE: K+ <2.5 mEq/L
      • ALSO SEVERE IF:
      • - Symptomatic (weakness, arrhythmia)
      • - ECG changes
      • - Ongoing K+ losses
      1. ●

         Action

         Get ECG

         Assess cardiac effects

         • ECG CHANGES:
         • - Flattened T waves
         • - Prominent U waves (pathognomonic)
         • - ST depression
         • - Prolonged QT interval
         • - Arrhythmias (PACs, PVCs, VT/VF)
         • ECG changes = urgent treatment
         1. ⚠

            Warning

            Check Magnesium (CRITICAL)

            Hypomagnesemia causes refractory hypokalemia

            • LOW Mg = REFRACTORY HYPOKALEMIA
            • Must replete Mg first/concurrently
            • Target Mg >2 mg/dL
            • Give MgSO4 2g IV if low
            • 40% of hypoK patients have low Mg
            1. ●

               Action

               Identify Cause

               Guides treatment duration

               • DECREASED INTAKE (rare alone)
               • GI LOSSES:
               • - Vomiting, NG suction
               • - Diarrhea, laxative abuse
               • RENAL LOSSES:
               • - Diuretics (thiazide, loop)
               • - Hyperaldosteronism
               • - RTA type 1, 2
               • - Hypomagnesemia
               • TRANSCELLULAR SHIFT:
               • - Insulin, beta-agonists
               • - Alkalosis
               • - Refeeding
               1. ◆

                  Decision

                  Treatment Route

                  Based on severity and symptoms

                  1. ●

                     Action

                     Oral Repletion

                     Mild-moderate, asymptomatic

                     • KCl 40-100 mEq/day in divided doses
                     • - 20-40 mEq PO q4-6h
                     • FORMULATIONS:
                     • - KCl tablets (slow-release)
                     • - KCl liquid (faster absorption)
                     • - K-rich foods (bananas, oranges)
                     • GI upset common with high doses
                     • Expected rise: 0.3 mEq/L per 10 mEq given
                     1. ●

                        Action

                        Monitoring

                        Recheck frequently

                        • SEVERE: Check K+ q2-4h
                        • MODERATE: Check K+ q6-8h
                        • MILD: Check next day
                        • Monitor for rebound hyperkalemia
                        • ECG if severe or on IV repletion
                        • Check Mg if K+ not responding
                        1. ✓

                           Outcome

                           Goals

                           Target and prevention

                           • Target K+ >4.0 mEq/L (ideally 4.0-4.5)
                           • Address underlying cause
                           • Consider K+-sparing diuretic if recurrent
                           • Diet education
                           • Monitor if on QT-prolonging drugs
                  2. ●

                     Action

                     IV Repletion

                     Severe or symptomatic

                     • PERIPHERAL IV:
                     • - Max 10-20 mEq/hr
                     • - Max concentration 40 mEq/L
                     • - Painful at higher concentrations
                     • CENTRAL LINE:
                     • - Max 20-40 mEq/hr
                     • - Higher concentrations OK
                     • - Cardiac monitoring required
                     • INFUSION:
                     • - 10 mEq in 100 mL NS over 1 hr
                     • - Recheck K+ after each 40 mEq