Hyperkalemia


THE CALL

OVERVIEW

  • Hyperkalemia: K > 5.0 mmol/L
  • Continuous cardiac monitoring is recommended if K > 6.5 mmol/L.

Etiology

  • Pseudohyperkalemia
    • Thrombocytosis, leukocytosis, hemolysis, venipuncture technique
  • Increased K+ intake/absorption (supplements)
  • Impaired renal excretion
  • Laboratory error
  • Medications
    • K+ sparing diuretics, ACE-I, ARBs
    • NSAIDs
    • Beta-blockers (Beta-1 selective): Atenolol, Metoprolol, Labetolol
    • Heparin therapy
    • Succinylcholine
    • Digitalis
    • Mannitol
    • Calcineurin inhibitors: Diazoxide, Minoxidil
    • Isoflurane
    • Cyclosporine
  • Pseudohypoaldosteronism, Hypoaldosteronism
  • Transcellular shifts
  • Exercise, Rhabdomyolysis
  • Hyperkalemic periodic paralysis
  • Cellular injury
  • Low Mg: check Mg Level

History/Symptoms

  • Check renal function status, medication hx
  • Fatigue, malaise
  • Weakness, paresthesias, paralysis, cramps
  • Palpitations
     

Physical Exam/Signs

  • Vitals: many signs indicating underlying disease may be present
    • Renal disease, medications, supplements, Addisons disease, trauma
  • Cardiac
    • Dysrhythmias (i.e. bradycardia, V. fib, heart block)
    • Asystole (severe or untreated)
  • Neurologic
    • Dysfunction usually non-specific
    • Decreased Deep Tendon Reflexes, decreased motor strength, muscular paralysis
    • Tetany
    • Focal neurological deficits

Diagnosis

  • Labs/Tests
    • Serum electrolyte levels
      • Serum sodium bicarbonate
      • Serum K+
    • Glucose (r/o DM sequelae)
    • Renal fxn tests/urinalysis
      • BUN/Cr
      • Spot urine (urine potassium & creatinine)
        • K+ excretion/transtubular gradient
    • CBC
    • Digoxin level
    • Arterial/venous blood gas
       
  • Imaging (r/o tumors, organ damage, etc)
    • Physician discretion and sign/Sx-dependent
       
  • Other Tests/Criteria: ECG
    • ECG - peaked T waves, prolonged PR, wide QRS, bradycardia, complete heart block, etc.
    • General
    • Mild (< 6.0 mEq/L) [< 6.0 mmol/L]
      • Peaked T-wave (tall/tented)
      • P-wave widens, loses height
      • Prolonged PR-interval
      • QRS-widening
    • Severe (> 6.0 mEq/L) [> 6.0 mmol/L]
      • Further or first QRS complex widening
      • Second part of QRS complex may become notched or slurred
      • Further P-wave widening, flattening and PR-interval prolongation
      • Widened QRS complex may merge with peaked T-waves to produce sine wave

Differential Dx

  • Hypocalcemia
  • Pseudohyperkalemia
  • Dehydration
  • Addisons disease
  • Sickle Cell dz
  • Acid-Base disorders

Treatment

C BIG K

  • Strategies
    • Establish pre-hospital IV access, ECG monitoring
      • ABCs, discontinue potassium-sparing drugs
      • Monitored bed, maintain IV access
    • Stabilize myocardium
      • Calcium Cl, gluconate
    • Redistribute K+ into cells
      • Glucose/Insulin, Sodium Bicarb, Beta-agonists
    • Excretion of K+
      • Acute situations
        • Exchange resins
        • Hemodialysis
      • Diuretics (for short term treatment, chronic disease)
        • Torsemide, Bumetanide, Furosemide IV
        • Combinations of loop and thiazide-like diuretics
          • Better efficacy, may decrease GFR
      • Mineralocorticoids (chronic disease)
        • Fludrocortisone: 0.1 - 0.3 mg/day

 

Hold K supplements (in IV, PO, etc.).
Mild (< 6.0 mEq/L)
  • Treat cause.
  • Consider:
    • Kayexalate (controversial; increased risk for colonic necrosis)
      • 15 - 30 g in sorbitol PO x1 or
      • 50 g/200 mL H2O retention enema
    • Lasix 40-80mg IV x 1 + NaCl bolus
  • Repeat K 4-6 h later.
Moderate (> 6.0-7.0 mEq/L)
Cardiac monitoring!--one or more of the following:
  • Kayexalate 15-30 g in sorbitol PO/NG/PR q4 - 6h PRN. CI if ileus.
    • Can cause Colonic Necrosis
    • Can also be given by retention enema: 50 g/200 mL NS or D20W, retained for 30 - 60 min q4h PRN.
    • Watch for evidence of fluid overload (especially CHF patients).
    • The only way of "removing" the K.
    • Onset: >2hr; Duration: 4-6 hr.
  • Glucose + Insulin:
    • Glucose: 1 amp D50 (50 mL of dextrose 50%) IVP
    • Insulin R: 5 - 10 U Regular insulin IVP over 15 min
      • Can put 10 U insulin in 500 mL of D10
    • Causes intracellular shift of K.
    • Lasts 1-2h.
    • Monitor glucose and adjust insulin accordingly.
  • Albuterol NEBs 5 - 20 mg over 10 min, repeat q4h PRN.
    • Intracellular shift of K.
    • 10mg drops K by 0.6 mmol/L
    • Onset: 30min; Duration: 2hr.
    • for patients on hemodialysis
  • NaHCO3 1 amp IV over 5 min PLUS 2 amps in 100 mL D5W over 30 - 60 min, especially if there is concurrent metabolic acidosis.
    • Drives K out at distal nephron
    • Onset: 1hr; Lasts 1-2hr.
  • Lasix 40-80mg IV
    • Onset: 15min; Duration: 2-3 hr.
  • Monitor K q1-2h until < 6.5 mEq/L.
Severe (> 7.0 mEq/L)
 Cardiac monitoring! -- one or more of the following:
  • Calcium
    • Ca Gluconate (preferred): 10-30cc IV Slow
      OR
    • Ca Chloride: 5-10 ml IV Slow over 10 min
      • Preferred in Liver failure pt.
    • Avoid Ca2+ if possible Digoxin toxic
  • Glucose + Insulin:
    • Glucose: 1 amp D50 (50 mL of dextrose 50%) IVP
    • Insulin R: 5 - 10 U Regular insulin IVP over 15 min
      • Can put 10 U insulin in 500 mL of D10
     
  • Albuterol NEBs 5 - 20 mg over 10 min, repeat q4h PRN. 
  • NaHCO3 1 amp IV over 5 min PLUS 2 amps in 100 mL D5W over 30 - 60 min, especially if there is concurrent metabolic acidosis, especially if there is concurrent metabolic acidosis.
  • Kayexalate 15-30 g in sorbitol PO/NG/PR q4 - 6h PRN. CI if ileus. Can also be given by retention enema: 50 g/200 mL NS retained for 30 - 60 min q4h PRN
  • Lasix 40-80mg IV
  • Consider hemodialysis

Disposition

  1. Admit if serum potassium > 5.5 mEq/L [5.5 mmol/L]
  2. Consult required dept (i.e. nephrology, cardiology, etc)
  3. Monitored bed or ICU if ECG changes
  4. Prognosis good, usually full resolution
  5. Nutrition modification
  6. Follow-up potassium levels 2 - 3 days
 

ADMISSION ORDERS:

1. Admit to:
2. Diagnosis: Hyperkalemia
3. Condition:
4. Vital Signs: q4h. Call physician if QRS complex >0.14 sec or BP >160/90, <90/60; P >120, <50; R>25, <10; T >38.5°C.
5. Activity: up as tolerated.
6. Allergies: Discontinue ACE inhibitors, potassium sparing diuretics.
6. Nursing: Inputs and outputs. Chart QRS complex width q1h.
7. Diet: Regular, no salt substitutes.
8. IV Fluids: D5NS at 125 cc/h
9. Special Medications:
  -Calcium gluconate (10% solution) 10-30 mL IV over 2-5 min. Keep 10 mL vial of calcium gluconate at bedside for emergent use.
  -Sodium bicarbonate 1 amp (50 mEq) IV over 5 min (give after calcium in separate IV).
  -Regular insulin 10 units IV push with 1 ampule of 50% glucose IV push.
  -Kayexalate 30-45 gm in sorbitol solution PO/NG/PR now and q3-4h.
  -Furosemide 40-80 mg IV, repeat prn.
  -Emergent dialysis if cardiac complications or renal failure.

10. Extras: ECG.

11. Labs: CBC, CMP, magnesium, chem-12. UA, urine specific gravity, urine sodium, pH, 24h urine potassium, creatinine.