Hyperkalemia

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Contents 1 Etiology 2 Clinical-manifestations 3 Laboratory 4 Diagnostic-procedures 5 Complications 6 Management 7 More General Terms 8 Additional Terms 9 References

Etiology

• pseudohyperkalemia

• excessively long tourniquet application before phlebotomy cause K+ to leak from muscle distal to the tourniquet
• hemolysis of specimen during or after phlebotomy
• thrombocytosis > 1E06/ mm3 or leukocytosis > 100,000/ mm3

• lysis of platelets or leukocytes during clot formation & retraction
• determine K+ from plasma rather than serum

• massive influx of K+ into serum

• intravenous K+ salts
• oral potassium

• dietary excess
• salt substitutes
• prescribed K+ replacements

• hemolysis
• rhabdomyolysis

• redistribution of K+ from within cells to plasma

• pharmacologic agents

• succinylcholine
• digitalis overdose
• beta-adrenergic receptor antagonists
• alpha-adrenergic receptor agonists
• arginine & lysine from hyperalimentation

• hyperosmolar states especially hyperglycemia

• insulin-deficiency

• metabolic acidosis with normal anion gap

• a decrease in pH of 0.1 increases K+ 0.6 meq/L

• hyperkalemic periodic paralysis

• may result in hyperkalemia or hypokalemia

• inadequate renal excretion

• adrenal disorders

• hyporeninemic hypoaldosteronism

• renal tubular acidosis ( RTA) IV

• Addison's disease

• defects in tubular secretion

• systemic lupus erythematosus ( SLE)
• obstructive uropathy
• sickle cell disease
• renal transplant

• renal failure

• special considerations in dialysis patients
• extrarenal mechanism of K+ elimination dominate

• constipation diminishes GI K+ elimination - fasting diminishes basal insulin levels

• pharmacologic agents:

• potassium-sparing diuretics

• amiloride
• triamterene
• spironolactone

• agents that inhibit secretion of aldosterone

• ACE inhibitors, ARBs
• non-steroidal anti-inflammatory drugs ( NSAIDs)
• heparin

• beta-blockers
• cytotoxic drugs
• cyclosporine A
• lithium
• trimethoprim ( Bactrim, Septra)
• pentamidine [3]

• diminished effective plasma volume

• CHF
• cirrhosis

• risk factors

• advanced age
• diabetes mellitus

• insulin secretion which results in translocation of K+ intracellularly is the body's major safegaurd against acute hyperkalemia

Clinical-manifestations

• muscle weakness
• perioral paresthesias
• 1 & 2 inconsistently present

Laboratory

• serum chemistries

• serum potassium: hyperkalemia
• serum creatinine: assess renal function
• serum urea nitrogen: obtain BUN/creatinine ratio
• serum glucose:

• hyperglycemia with insulin deficiency

• serum creatine kinase to assess rhabdomyolysis

Diagnostic-procedures

• electrocardiogram

• peaked T waves especially in precordial leads
• prolongation of PR interval
• loss of P wave
• no prolongation of QT interval
• widening of QRS complex

• late change
• degeneration into sine wave before patient arrest

• ventricular fibrillation
• asystole

Complications

• ventricular arrhythmias
• cardiac conduction defects
• cardiac arrest

Management

• serum K+ < 6.5 meq/L & no EKG changes or peaked T waves only

• identify & correct underlying etiology
• loop diuretics

• advanced renal disease
• tubular defects
• hyporeninemic hypoaldosteronism

• fludrocortisone ( Florinef)

• oral NaHCO3 to enhance Na+ delivery to the distal tubules & K+ excretion
• Kayexalate with 1 mL of 70% sorbitol/g Kayexalate

• serum K+ > 8 meq/L or EKG changes beyond peaked T waves

• continuous EKG monitoring
• IV access
• 10-30 mL of 10% calcium gluconate IV push

• transiently stabilizes myocardial cells
• does not lower serum K+
• onset: minutes; duration: 1/2 hour

• NaHCO3 drip (may not be effective in dialysis patients)
• IV glucose + insulin

• 200 to 500 mL of 10% dextrose
• 10 units of insulin IV or SC
• over 30 minutes
• may repeat several times

• beta 2 adrenergic receptor agonists

• albuterol

• Kayexalate with 1 mL of 70% sorbitol/g Kayexalate

• 25-50 g of Kayexalate
• peak effect seen in 4 hours

• dialysis

• hemodialysis
• peritoneal dialysis

• continuing influx of K+ into plasma from:

• rhabdomyolysis
• tissue necrosis mandates aggressive treatment of hyperkalemia

• avoid, discontinue or decrease dosage of drugs that inhibit K+ excretion; threshold for action 5.5 meq/L [3]
• low potassium diet

More General Terms

• sign/symptom

Additional Terms

• calcium gluconate
• familial periodic paralysis (hyperkalemic, normokalemic, hypokalemic, HYPP, NKPP, HYPOPP)
• HCO3- (bicarbonate)
• polystyrene sulfonate (Kayexalate, Kalimate)
• potassium (K+) in serum/plasma
• renal tubular acidosis (RTA) type IV

References

1. Harrison's Principles of Internal Medicine, 13th ed. Companion Handbook, Isselbacher et al (eds), McGraw-Hill Inc. NY, 1995, pg 831
2. Saunders Manual of Medical Practice, Rakel (ed), WB Saunders, Philadelphia, 1996, pg 671-673
3. Medical Knowledge Self Assessment Program (MKSAP) 11, 14, 15, American College of Physicians, Philadelphia 1998, 2006, 2009

hyperkalemia