โšก Chapter 87: Hyperkalemia

๐Ÿ“˜ Nelson's Pediatric Decision-Making Strategies

Renal failure ยท Hemolysis ยท Rhabdomyolysis ยท Tumor lysis ยท Acidosis ยท Adrenal insufficiency ยท Type 4 RTA ยท Pseudohyperkalemia

๐Ÿ” Clinical Decision-Making: Hyperkalemia in Children

๐Ÿ“Š Definitions
โ€ข Hyperkalemia: serum K >5.5 mEq/L (mild), >6.5 mEq/L (severe)
โ€ข EKG changes: peaked T waves โ†’ widened QRS โ†’ sine wave โ†’ ventricular fibrillation
โ€ข Medical emergency: treat immediately if K >6.5 or EKG changes
โš ๏ธ Causes of Hyperkalemia
โ€ข Increased intake: salt substitutes, IV KCl, blood transfusion, TPN
โ€ข Decreased excretion: acute kidney injury (AKI), chronic kidney disease (CKD), type 4 RTA (hypoaldosteronism), adrenal insufficiency, medications (ACEi, ARBs, K-sparing diuretics, NSAIDs, TMP-SMX)
โ€ข Transcellular shift: metabolic acidosis (H+ moves into cells, K+ out), tumor lysis syndrome, rhabdomyolysis, hemolysis, hyperkalemic periodic paralysis
๐Ÿšจ Emergency Treatment (Stabilize Membrane)
โ€ข Calcium gluconate (10%): 0.5 mL/kg IV over 2-5 min โ†’ protects heart (does NOT lower K)
โ€ข Shift K into cells: insulin + glucose (0.1 U/kg IV insulin, then 0.5 g/kg glucose), albuterol nebulized
โ€ข Remove K: sodium polystyrene sulfonate (Kayexalate) oral/rectal, loop diuretics (furosemide), dialysis (for severe/refractory)
๐Ÿฉบ Chronic Management
โ€ข Low-potassium diet, avoid medications that impair K excretion
โ€ข Loop diuretics (furosemide), K binders (patiromer, sodium zirconium cyclosilicate)
โ€ข Treat underlying cause (adrenal insufficiency โ†’ hydrocortisone/fludrocortisone)

๐Ÿ“Œ Decision strategy: Check EKG immediately if K >6.5 or patient symptomatic. Calcium gluconate first if EKG changes. Then shift K into cells (insulin + glucose, albuterol). Then remove K (diuretics, Kayexalate, dialysis).