Diagnosis

Hyperkalemia

Etiology

Cause [wm1][4ku]

• Increased K intake

  • Iatrogenic: intravenous or oral potassium supplementation, blood transfusion

• Decreased potassium excretion

  • Renal failure (oliguria)

  • Primary adrenal insufficiency: Addison disease, adrenal hyperplasia, hypoaldosteronism

  • Drug side effects: NSAIDs, diuretics, spironolactone, Cyclosporin A, ACE inhibitors/AT-blockers (RAAS), trimethoprim, tacrolimus, pentamidine, Beta blockers, Digoxin toxicity, amiloride, Fluoride toxicity, Methotrexate, Propofol infusion syndrome, Succinylcholine, Heparins, Penicillin G

• Transcellular potassium shifts

  • Acidosis: hydrogen ion enters a cell --> decreased K+ uptake by the cell in order to maintain electrical neutrality

  • Diabetes type 1 (insulin deficiency)

  • Dehydration

  • Acute tubular necrosis

  • Cell destruction:

    • Pseudohyperkalemia due to hemolysis in the laboratory, leukocytosis, or thrombocytosis

    • Burns

    • Tumor lysis syndrome

    • Rhabdomyolysis

    • Strenuous or prolonged exercise

    • Malignant hyperthermia

Pathophysiology [4ku]

1. The sodium-potassium pump

   • Intracellular potassium concentration: 140 mEq/L

   • Extracellular potassium concentration: 4 to 5 mEq/L

2. 95-98% of the total body potassium is found in the intracellular space

3. Under normal conditions, approximately 90% of potassium excretion occurs in the urine, with less than 10% of potassium excreted through sweat or stool

4. Elevated renal potassium excretion:

   • Aldosterone

   • Diuretics

   • WNK1 and WNK4

   • High levels of serum potassium

   • A high flow of urine (osmotic diuresis)

   • Presence of negative ions in the distal tubule (bicarbonate)

Complications [4ku]

• Cardiac arrest

• Weakness

• Arrhythmias

• Paralysis

Epidemiology

Incidence per 100.000 [h6u][swm][wm1][3hv][y7o]

Prevalence per 100.000 [h6u][swm][wm1][3hv][y7o]

Approach

• Blood test: Complete blood cell count, serum electrolytes, glucose, creatinine, blood urea nitrogen, osmolality, digoxin level test, uric acid/phosphorous (for tumor lysis syndrome)

• Blood gas (acid-base disorders)

• Urine: stix, urine electrolyte, osmolality

• Ultrasound abdomen (renal circulation, post-renal obstruction)

• ECG

• Digitoxin level

Treatment

1. Avoid high-potassium foods: [y9d]

   • Salt substitutes

   • Yogurt and milk

   • Molasses

   • Seaweed

   • Chocolate

   • Cereal, wheat, granola

   • Vegetables (acorn squash, artichoke, bamboo shoots, beets, broccoli, brussel sprouts, chinese cabbage, carrots, greens (except kale), kohlrabi, mushrooms (canned), parsnips, potatoes, pumpkin, rutabagas, spinach, tomatoes, vegetable juices)

   • Dried fruit (apricot, dates, figs, raisins, prunes)

   • Nuts and seeds

   • Dried peas and beans (lima beans, black beans, refried beans, lentils, legumes)

   • Fruit and juice (apricot, avocado, banana, cantaloupe, grapefruit, honeydew, kiwi fruit, mango, nectarine, orange, papaya, pomegranate, prune)

2. Medical treatment: [cue][nsi][o2e]

   1. If K > 5.0 mmol/l:

      • Patiromer (Veltassa): 8.4 g orally per day, can titrate up to 25.2 g per day

      • Sodium polystyrene sulfonate: 15 g orally once per day; can repeat up to 4 times per day

      • Sodium zirconium cyclosilicate (Lokelma): 10 g orally 3 times per day

   2. If K > 6.0 mmol/l:

      • Intravenous calcium if ECG-changes for immediate effect:

        • Calcium gluconate 1-2 g or 10 to 20 mL of 10 percent solution IV over 2-3 minutes

        • Calcium chloride 500-1,000 mg

      • Diuretics: give with saline if volume depletion

        • Furosemide: 20 to 40 mg iv/po

        • Bumetanide: 0.5 to 1 mg iv/po

      • Insulin with glucose: 10 units IV with 50 mL of 50 percent glucose

      • Albuterol (Ventolin): 10 to 20 mg by nebulizer over 10 minutes

   3. If increasing K:

      • Hemodialysis

Differential diagnoses

Acidosis, Adrenal insufficiency, Blood transfusion, Burn wound, Congenital adrenal hyperplasia, Drug side effects, Electrical injury, Hemolysis, Hypoaldosteronism, Hypocalcemia, Hypoinsulinemia, Lab error, Metabolic acidosis, Renal failure, Rhabdomyolysis, Tumor lysis syndrome