Hypokalemia in Emergency Medicine Workup

  • Author: David Garth, MD; Chief Editor: Erik D Schraga, MD   more...
 
Updated: Apr 25, 2012
 

Laboratory Studies

  • Serum potassium level < 3.5 mEq/L (3.5 mmol/L)[8]
  • BUN and creatinine level
  • Glucose, calcium, and/or phosphorus level if coexistent electrolyte disturbances are suspected.
  • Magnesium levels are unreliable and typically do not change management, since patients with hypokalemia almost always have coincident hypomagnesemia and should be treated empirically.
  • Consider digoxin level if the patient is on a digitalis preparation; hypokalemia can potentiate digitalis-induced arrhythmias.
  • Consider arterial blood gas (ABG): Alkalosis can cause potassium to shift from extracellular to intracellular.
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Imaging Studies

  • CT scan of the adrenal glands is indicated if mineralocorticoid excess is evident (rarely needed emergently).
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Other Tests

  • Electrocardiography
    • T-wave flattening or inverted T waves
    • Prominent U wave that appears as QT prolongation (see the image below)Prominent U waves after T waves in hypokalemia. Prominent U waves after T waves in hypokalemia.
    • ST-segment depression
    • Ventricular arrhythmias (eg, premature ventricular contractions [PVCs], torsade de pointes, ventricular fibrillation)[5]
    • Atrial arrhythmias (eg, premature atrial contractions [PACs], atrial fibrillation)
  • Thyroid screening studies - Thyroid-stimulating hormone (TSH), free T3, and free T4 in patients with tachycardia, especially Asian patients[7]
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Contributor Information and Disclosures
Author

David Garth, MD  Attending Physician, Department of Emergency Medicine, Mary Washington Hospital

David Garth, MD is a member of the following medical societies: American Academy of Emergency Medicine

Disclosure: Nothing to disclose.

Specialty Editor Board

Robin R Hemphill, MD, MPH  Associate Professor, Director, Quality and Safety, Department of Emergency Medicine, Emory University School of Medicine

Robin R Hemphill, MD, MPH is a member of the following medical societies: American College of Emergency Physicians and Society for Academic Emergency Medicine

Disclosure: Nothing to disclose.

Francisco Talavera, PharmD, PhD  Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Medscape Salary Employment

Howard A Bessen, MD  Professor of Medicine, Department of Emergency Medicine, University of California, Los Angeles, David Geffen School of Medicine; Program Director, Harbor-UCLA Medical Center

Howard A Bessen, MD is a member of the following medical societies: American College of Emergency Physicians

Disclosure: Nothing to disclose.

John D Halamka, MD, MS  Associate Professor of Medicine, Harvard Medical School, Beth Israel Deaconess Medical Center; Chief Information Officer, CareGroup Healthcare System and Harvard Medical School; Attending Physician, Division of Emergency Medicine, Beth Israel Deaconess Medical Center

John D Halamka, MD, MS is a member of the following medical societies: American College of Emergency Physicians, American Medical Informatics Association, Phi Beta Kappa, and Society for Academic Emergency Medicine

Disclosure: Nothing to disclose.

Chief Editor

Erik D Schraga, MD  Staff Physician, Department of Emergency Medicine, Mills-Peninsula Emergency Medical Associates

Disclosure: Nothing to disclose.

Additional Contributors

I would like to thank my wife, Mary. Her patience, love, and reassurance, are my bedrock.

References

  1. [Guideline] ECC Committee, Subcommittees and Task Forces of the American Heart Association. 2005 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation. Dec 13 2005;112(24 Suppl):IV1-203. [Medline]. [Full Text].

  2. Latronico N, Shehu I, Seghelini E. Neuromuscular sequelae of critical illness. Curr Opin Crit Care. Aug 2005;11(4):381-90. [Medline].

  3. Ingram TC, Olsson JM. In brief: hypokalemia. Pediatr Rev. Sep 2008;29(9):e50-1. [Medline].

  4. Seigel JD, Di Palma JA. Medical treatment of constipation. Clin Colon Rectal Surg. 2005;18(2):76-80.

  5. Reactions Weekly. Dextrose: First report of ventricular arrhythmia: case report. Reactions Weekly. 2005;1046:11.

  6. Greenfeld D, Mickley D, Quinlan DM, Roloff P. Hypokalemia in outpatients with eating disorders. Am J Psychiatry. Jan 1995;152(1):60-3. [Medline]. [Full Text].

  7. Goldberger ZD. Images in cardiovascular medicine. An electrocardiogram triad in thyrotoxic hypokalemic periodic paralysis. Circulation. Feb 13 2007;115(6):e179-80. [Medline].

  8. [Guideline] Assadi F. Diagnosis of hypokalemia: a problem-solving approach to clinical cases. Iran J Kidney Dis. Jul 2008;2(3):115-22. [Medline].

  9. Becker AE, Grinspoon SK, Klibanski A, Herzog DB. Eating disorders. N Engl J Med. Apr 8 1999;340(14):1092-8. [Medline].

  10. Cohn JN, Kowey PR, Whelton PK, Prisant LM. New guidelines for potassium replacement in clinical practice: a contemporary review by the National Council on Potassium in Clinical Practice. Arch Intern Med. Sep 11 2000;160(16):2429-36. [Medline].

  11. Dominiczak AF, Semple PF, Fraser R, Lever AF, Wallace AM. Hypokalaemia in alcoholics. Scott Med J. Aug 1989;34(4):489-94. [Medline].

  12. Gennari FJ. Hypokalemia. N Engl J Med. Aug 13 1998;339(7):451-8. [Medline].

  13. Halperin ML, Kamel KS. Potassium. Lancet. Jul 11 1998;352(9122):135-40. [Medline].

  14. Howes LG. Which drugs affect potassium?. Drug Saf. Apr 1995;12(4):240-4. [Medline].

  15. Kleinfeld M, Borra S, Gavani S, Corcoran A. Hypokalemia: are elderly females more vulnerable?. J Natl Med Assoc. Nov 1993;85(11):861-4. [Medline].

  16. Küng M. Parenteral adrenergic bronchodilators and potassium. Chest. Mar 1986;89(3):322-3. [Medline].

  17. Mandal AK. Hypokalemia and hyperkalemia. Med Clin North Am. May 1997;81(3):611-39. [Medline].

  18. Paice BJ, Paterson KR, Onyanga-Omara F, Donnelly T, Gray JM, Lawson DH. Record linkage study of hypokalaemia in hospitalized patients. Postgrad Med J. Mar 1986;62(725):187-91. [Medline].

  19. Singhal PC, Venkatesan J, Gibbons N, Gibbons J. Prevalence and predictors of rhabdomyolysis in patients with hypokalemia. N Engl J Med. Nov 22 1990;323(21):1488. [Medline].

  20. Walters EG, Barnes IC. A survey of hypokalaemia in patients of general practitioners. Br J Clin Pract. May 1988;42(5):192-5. [Medline].

  21. Zull DN. Disorders of potassium metabolism. Emerg Med Clin North Am. Nov 1989;7(4):771-94. [Medline].

 
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Prominent U waves after T waves in hypokalemia.
 
 
 
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