Hyperkalemia

ER

• Definition: serum potassium > 5.5 mEq/L
• Causes:
  • hemolysis/thrombocytosis/leukocytosis (lab artifact);
  • cellular breakdown (rhabdomyolysis);
  • impaired excretion (renal failure);
  • transcellular shift (acidosis);
  • hypoaldosteronism;
  • medications (ACE inhibitors, potassium-sparing diuretics).

Clinical features

• Cardiac: ventricular fibrillation, AV blocks, asystole
• Neuromuscular: weakness, paresthesias, areflexia, ascending paralysis
• GI: nausea, vomiting, diarrhea

Evaluation

• ECG is essential in all hyperkalemic patients.
• If ECG changes present, start emergency treatment immediately.

ECG changes

• Tall peaked T waves
• Flattening of the P wave
• Prolonged PR interval
• QRS widening

Treatment summary

Mechanism	Therapy	Dose & Route	Notes
Cardiac membrane stabilization	Calcium chloride or calcium gluconate	1 g IV (Ca gluconate) or 2 g IV (Ca chloride)	First medication if widened QRS
Shift potassium into cells	Regular insulin + dextrose	10 units insulin IV + 100 mL 50% dextrose IV	Use 5 units IV insulin if renal dysfunction
	Albuterol	10–15 mg nebulized
	Sodium bicarbonate	50–100 mL IV	For severely acidotic patients
Remove potassium from body	Furosemide	40–80 mg IV	Ineffective in ESRD
	Hemodialysis		Emergently in cardiac arrest, urgently in renal failure

• Sodium polystyrene sulfonate (Kayexalate) is not effective for acute management and may cause GI necrosis/perforation.

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Pediatrics

Causes

1. Potassium Shifts from the ICF to the ECF

   • Metabolic acidosis
   • Strenuous exercise
   • Insulin deficiency
   • Hyperglycemia

2. Medications

   • Potassium-sparing diuretics (spironolactone)
   • Potassium supplements (e.g., potassium chloride)
   • ACE inhibitors
   • Chemotherapeutic agents

3. Impaired Renal Potassium Excretion

   • Renal failure
   • Renal tubular acidosis (RTA)
   • Adrenal insufficiency
   • Congenital adrenal hyperplasia (CAH)

4. Movement of Potassium Out of Cells During or After Specimen Collection (Pseudohyperkalemia)

   • Hemolysis
   • Tumor lysis syndrome

Hyperkalemia

• Serum K+ > 5.5 mEq/L
  • Mild: S K+ = 5.5-6.5 mEq/L
  • Moderate: S K+ = 6.5-8.00 mEq/L
  • Severe: S K+ >8 mEq/L

Lab Tests

• Chemistry for other electrolytes
• Glucose level
• Urinalysis, urine potassium, and creatinine
• ECG

ECG Changes

• Prolonged PR interval
• Peaked T wave
• Wide QRS complex
• Absent P; flattening
• Asystole, VF

Clinical Features

• Muscle weakness, decreased deep tendon reflexes, ileus, tingling of the mouth and extremities, malaise, and tetany.

Hyperkalemia Treatment

First Line

• Salbutamol nebulization: Shifts K into the cells. Effect appears within 20-30 minutes.

Second Line

• Insulin and Glucose infusion: Shifts K into cells. Effect appears within 10-20 minutes.

Third Line

• Furosemide: Excretes K through renal tubules. Effect appears within 60-120 minutes.
• Calcium Gluconate: Given in moderate to severe hyperkalemia to stabilize cardiac conduction. Z (ECG CHANGES GIVE IMMEDIATLY)
• Calcium Resonium (Kayexalate): Antagonizes K effect. Effect appears within 60-120 minutes. Z (PROTECT HEART AND ORGANS AGAINST K EFFECT)

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