eMedicine Specialties > Pediatrics: Cardiac Disease and Critical Care Medicine > Critical Care

Hyperkalemia: Differential Diagnoses & Workup

Author: Michael J Verive, MD, Medical Director, Pediatric Intensive Care, Department of Pediatrics, St Mary's Hospital for Women and Children
Contributor Information and Disclosures

Updated: Jan 4, 2010

Differential Diagnoses

Acidosis, Metabolic
Head Trauma
Acute Tubular Necrosis
Rhabdomyolysis
Burns, Electrical
Toxicity, Digitalis
Burns, Thermal
Tumor Lysis Syndrome
Congenital Adrenal Hyperplasia

Other Problems to Be Considered

Acute renal failure
Drug overdose or poisoning

Workup

Laboratory Studies

  • Laboratory studies depend on the etiology of hyperkalemia but may include the following:
    • Serum electrolyte tests
    • Serum BUN and creatinine tests
    • Urinalysis (UA)
  • Depending on the etiology or on clinical suspicion, other studies to consider include the following:
    • Arterial or free-flowing venous blood gas sampling (for acid-base disorders): Capillary blood gas sampling should not routinely be used to evaluate for hyperkalemia due to significant risks of factitious hyperkalemia.
    • Serum uric acid and phosphorous tests (for tumor lysis syndrome)
    • Serum creatinine phosphokinase (CPK) and calcium measurements (for rhabdomyolysis)
    • Urine myoglobin test (for crush injury or rhabdomyolysis; suspect if UA reveals blood in the urine but no RBCs are seen on urine microscopy)
    • Specific drug level tests for suspected toxicity (digoxin)
    • CBC count (for thrombocytosis, leukocytosis, or malignancy)
    • Urine electrolyte tests, including potassium and osmolality (osm) tests
    • Plasma osm test
  • When the etiology of hyperkalemia remains unclear, calculation of the transtubular potassium gradient (TTKG) using the following formula may be useful:

TTKG = (K+ urine X Osm plasma)/(K+ plasma X Osm urine)

  • The normal TTKG varies from 5-15. In the setting of hyperkalemia with normal renal excretion of potassium, the TTKG should be greater than 10. A TTKG of less than 8 in the setting of hyperkalemia implies inadequate potassium excretion, which is usually secondary to aldosterone deficiency or unresponsiveness. Checking a serum aldosterone level may be helpful.

Imaging Studies

  • Imaging studies are not generally indicated, except to assess the primary disease state (eg, excluding obstructive uropathy as a cause for acute renal failure).

Other Tests

An ECG is essential in all children in whom hyperkalemia is suspected. ECG reveals the sequence of changes as follows:

  • Serum K+ 5.5-6.5 mEq/L - Tall, peaked T waves with narrow base, best seen in precordial leads (as is shown in the image below)

  • Peaked T waves.

    Peaked T waves.

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    Peaked T waves.

    Peaked T waves.

  • Serum K+ 6.5-8.0 mEq/L - Peaked T waves, prolonged PR interval, decreased or disappearing P wave, widening of QRS, amplified R wave
  • Serum K+ greater than 8.0 mEq/L - Absence of P wave; progressive QRS widening, intraventricular/fascicular/bundle branch blocks; progressive widening of QRS, eventually merging with the T wave just before cardiac arrest, forming the sine wave pattern (as is shown in the image below)

  • Sinusoidal wave.

    Sinusoidal wave.

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    Sinusoidal wave.

    Sinusoidal wave.

More on Hyperkalemia

Overview: Hyperkalemia
Differential Diagnoses & Workup: Hyperkalemia
Treatment & Medication: Hyperkalemia
Follow-up: Hyperkalemia
Multimedia: Hyperkalemia
References
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References

  1. Shaffer SG, Kilbride HW, Hayen LK, Meade VM, Warady BA. Hyperkalemia in very low birth weight infants. J Pediatr. Aug 1992;121(2):275-9. [Medline].

  2. Bhananker SM, Ramamoorthy C, Geiduschek JM, et al. Anesthesia-related cardiac arrest in children: update from the Pediatric Perioperative Cardiac Arrest Registry. Anesth Analg. Aug 2007;105(2):344-50. [Medline].

  3. Papaioannou V, Dragoumanis C, Theodorou V, Pneumatikos I. The propofol infusion 'syndrome' in intensive care unit: from pathophysiology to prophylaxis and treatment. Acta Anaesthesiol Belg. 2008;59(2):79-86. [Medline].

  4. Schweiger B, Moriarty MW, Cadnapaphornchai MA. Case report: severe neonatal hyperkalemia due to pseudohypoaldosteronism type 1. Curr Opin Pediatr. Apr 2009;21(2):269-71. [Medline].

  5. Mattu A, Brady WJ, Robinson DA. Electrocardiographic manifestations of hyperkalemia. Am J Emerg Med. Oct 2000;18(6):721-9. [Medline].

  6. Lorenz JM, Kleinman LI, Markarian K. Potassium metabolism in extremely low birth weight infants in the first week of life. J Pediatr. Jul 1997;131(1 Pt 1):81-6. [Medline].

  7. Schweiger B, Moriarty MW, Cadnapaphornchai MA. Case report: severe neonatal hyperkalemia due to pseudohypoaldosteronism type 1. Curr Opin Pediatr. Apr 2009;21(2):269-71. [Medline].

  8. Gurnaney H, Brown A, Litman RS. Malignant hyperthermia and muscular dystrophies. Anesth Analg. Oct 2009;109(4):1043-8. [Medline].

  9. Cummings CC, McIvor ME. Fluoride-induced hyperkalemia: the role of Ca2+-dependent K+ channels. Am J Emerg Med. Jan 1988;6(1):1-3. [Medline].

  10. Piotrowski AJ, Fendler WM. Hyperkalemia and cardiac arrest following succinylcholine administration in a 16-year-old boy with acute nonlymphoblastic leukemia and sepsis. Pediatr Crit Care Med. Mar 2007;8(2):183-5. [Medline].

  11. [Guideline] Advanced life support. In: 2005 International Consensus Conference on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science with Treatment Recommendations. Circulation 2005 Nov 29;112(22 Suppl):III25-54. [Full Text].

  12. Bercovitz RS, Greffe BS, Hunger SP. Acute tumor lysis syndrome in a 7-month-old with hepatoblastoma. Curr Opin Pediatr. Nov 18 2009;[Medline].

  13. Behrman R, Kliegman R, Jenson H. Nelson Textbook of Pediatrics. 17th Ed. Philadelphia, PA: WB Saunders; 2004.

  14. Brenner B. Brenner & Rector's The Kidney. 7th ed. St Louis, MO: WB Saunders; 2004.

  15. Finberg L, Kravath R, Hellerstein S. Potassium. In: Water and Electrolytes in Pediatrics: Physiology, Pathophysiology, and Treatment. Philadelphia, PA: WB Saunders; 1993:70-1.

  16. Goldfrank LR, ed. Goldfrank's Toxicologic Emergencies. 6th ed. Stanford, CT: Appleton & Lange; 1998.

  17. Kokko, JP, Tannen RL. Potassium disorders. In: Fluids and Electrolytes. Philadelphia, PA: WB Saunders; 1990:195-300.

  18. Lieh-Lai, M, Asi-Bautista, M, Ling-McGeorge, K. Hyperkalemia. In: Pediatric Acute Care Handbook. Philadelphia, PA: Lippincott, Williams, & Wilkins; 1995.

  19. Maxwell MH, Kleeman CR. Maxwell and Kleeman's Clinical Disorders of Fluid and Electrolyte Metabolism. 5th Ed. New York, NY: McGraw-Hill; 1994.

  20. Odegard KC, DiNardo JA, Kussman BD, et al. The frequency of anesthesia-related cardiac arrests in patients with congenital heart disease undergoing cardiac surgery. Anesth Analg. Aug 2007;105(2):335-43. [Medline].

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Further Reading

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Keywords

hyperkaliemia, hyperpotassemia, potassium, potassium level, serum potassium level, K+, potassium excretion, potassium intake, hemolysis, phlebotomy, fictitious hyperkalemia, pseudohyperkalemia, true hyperkalemia, renal insufficiency, treatment, diagnosis, symptoms

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Contributor Information and Disclosures

Author

Michael J Verive, MD, Medical Director, Pediatric Intensive Care, Department of Pediatrics, St Mary's Hospital for Women and Children
Michael J Verive, MD is a member of the following medical societies: American Academy of Pediatrics, American College of Chest Physicians, and Society of Critical Care Medicine
Disclosure: Nothing to disclose.

Medical Editor

G Patricia Cantwell, MD, Associate Clinical Professor, Department of Pediatrics, University of Miami; Director of Pediatric Critical Care Medicine, Miller School of Medicine, Jackson Children's Hospital
G Patricia Cantwell, MD is a member of the following medical societies: American Academy of Pediatrics, American College of Emergency Physicians, American Heart Association, American Trauma Society, National Association of EMS Physicians, Society of Critical Care Medicine, and Wilderness Medical Society
Disclosure: Nothing to disclose.

Pharmacy Editor

Mary L Windle, PharmD, Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy, Pharmacy Editor, eMedicine
Disclosure: Nothing to disclose.

Managing Editor

Barry J Evans, MD, Assistant Professor of Pediatrics, Temple University Medical School; Director of Pediatric Critical Care and Pulmonology, Associate Chair for Pediatric Education, Temple University Children's Medical Center
Barry J Evans, MD is a member of the following medical societies: American Academy of Pediatrics, American College of Chest Physicians, American Thoracic Society, and Society of Critical Care Medicine
Disclosure: Nothing to disclose.

CME Editor

Mary E Cataletto, MD, Associate Director, Division of Pediatric Pulmonology, Winthrop University Hospital; Professor of Clinical Pediatrics, State University of New York at Stony Brook; Director of Children's Sleep Services, Winthrop University Hospital
Mary E Cataletto, MD is a member of the following medical societies: American Academy of Pediatrics and American College of Chest Physicians
Disclosure: Shering Plough Pharmaceuticals Honoraria Consulting

Chief Editor

Timothy E Corden, MD, Associate Professor of Pediatrics, Co-Director, Policy Core, Injury Research Center, Medical College of Wisconsin; Associate Director, PICU, Children's Hospital of Wisconsin
Timothy E Corden, MD is a member of the following medical societies: American Academy of Pediatrics, Phi Beta Kappa, Society of Critical Care Medicine, and Wisconsin Medical Society
Disclosure: Nothing to disclose.

 
 
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