Hypokalemia: Difference between revisions
 
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*Central nervous system
*Central nervous system
**[[Weakness]]  
**[[Weakness]]  
**[[Cramps]]  
**[[myalgia|Cramps]]  
**[[Hyporeflexia]]
**Hyporeflexia  
*Gastrointestinal
*Gastrointestinal
**[[Ileus]]  
**[[Ileus]]  
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**[[Metabolic alkalosis]]
**[[Metabolic alkalosis]]
*Cardiovascular
*Cardiovascular
**PACs/PVCs  
**[[PACs]]/[[PVCs]]
**[[ACLS: Bradycardia|Bradycardia]] or atrial/junctional tachycardia  
**[[ACLS: Bradycardia|Bradycardia]] or [[atrial tachycardia|atrial]]/[[junctional tachycardia]]
**[[AV block]]  
**[[AV block]]  
**[[Tachycardia (wide)|Ventricular tachycardia]], [[Adult pulseless arrest|Ventricular fibrillation]]
**[[Tachycardia (wide)|Ventricular tachycardia]], [[Adult pulseless arrest|Ventricular fibrillation]]


==Differential Diagnosis==
==Differential Diagnosis<ref>In: Tintinalli JE, Stapczynski J, Ma O, Yealy DM, Meckler GD, Cline DM. eds. Tintinalli’s Emergency Medicine: A Comprehensive Study Guide, 8e. McGraw-Hill; Accessed November 29, 2020. https://accessmedicine.mhmedical.com/content.aspx?bookid=1658&sectionid=109381281</ref>==
[[File:Hypokalemia.png|thumb|Differential diagnosis of hypokalemia]]
[[File:Hypokalemia.png|thumb|Differential diagnosis of hypokalemia]]
===Intracellular Shift===
===Intracellular Shift===
*Alkalosis (each 0.10 rise in pH causes 0.5 decrease)
*Alkalosis (each 0.10 rise in pH causes 0.5 decrease)
*[[Insulin]]
*[[Insulin]]
*B-agonist
*[[Beta agonists]]
*[[Hypokalemic periodic paralysis]]
*[[Hypokalemic periodic paralysis]]


===Decreased intake===
===Decreased intake===
*Special diets or those low in potassium
*Special diets or those low in potassium
*Chronic alcohol abuse
*Chronic [[alcohol Abuse|alcohol abuse]]
*Fasting
*Eating disorders
 
===Increased loss===
===Increased loss===
*GI
*GI
**Vomiting, diarrhea, fistula
**[[Vomiting]], [[diarrhea]], fistula
*Renal
*Renal
**Diuretics
**[[Diuretics]]
**Hyperaldo
**Osmotic diuresis (late-presenting [[Diabetic ketoacidosis|DKA]])
**Exercise
**Hyperaldosteronism
**[[Hypercalcemia]]
**[[Hypercalcemia]]
**[[Hypomagnesemia]]
**[[Hypomagnesemia]]
*Increased sweat loss
**Heavy exercise
**Heat stroke
**Fever
===Drugs===
===Drugs===
*[[Penicillins]]
*[[Penicillins]]
*[[Lithium toxicity|Lithium]]
*[[Lithium toxicity|Lithium]]
*L-dopa
*L-dopa
*[[Theophylline]], methlxanthines
*[[Theophylline]], methylxanthines (e.g. [[caffeine]]
*[[Insulin]]
*[[Insulin]]
*Barium
*Barium
*[[Quinine]]
*[[Quinine]]
*Catecholamines
*Catecholamines
===Other===
*Acute leukemia and lymphomas
*Recovery from megaloblastic anemia
*Hypothermia (accidental or induced)


==Evaluation==
==Evaluation==
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**Severe hypokalemia = <2.5meq/L
**Severe hypokalemia = <2.5meq/L
*Always check magnesium
*Always check magnesium
**Na+/K+ ATPase pump requires Mg to function, therefore low Mg can lead to refractory hypoK
*Suggestive [[ECG]] findings:  
*Suggestive [[ECG]] findings:  
**[[ST segment depression]]  
**[[ST segment depression]]  
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**KCl tablet (elixir form available but has poor taste)
**KCl tablet (elixir form available but has poor taste)
**K-Dur (extended release tablet) is large and may be difficult to swallow
**K-Dur (extended release tablet) is large and may be difficult to swallow
**If sending patient home can also increase food intake of potassium as an alternative or supplementing potassium tablets. Printable table that can be given to the patient available at this reference: <ref>[https://www.mayoclinic.org/drugs-supplements/potassium-supplement-oral-route-parenteral-route/description/drg-20070753?p=1 Potassium Supplement (Oral Route, Parenteral Route) from Mayo Clinic]</ref>.
*Intravenous potassium
*Intravenous potassium
**Must be given in dilute solutions at slow rate (10meq/hour) to minimize side effects and cardiac toxicity
**Must be given in dilute solutions at slow rate (10meq/hour) to minimize side effects and cardiac toxicity
**Generally should not give more than 40mEq via IV
**Generally should not give more than 40mEq via IV
**Side effects: Local tissue burning, phelbitis, sclerosis
**Side effects: Local tissue burning, phlebitis, sclerosis
*Also treat [[Hypomagnesemia]] if present
*Also treat [[Hypomagnesemia]] if present
*Re-check ECG after treatment <ref>Slovis, Corey. "Electrolyte Emergencies". Presentation.</ref>
*Re-check ECG after treatment <ref>Slovis, Corey. "Electrolyte Emergencies". Presentation.</ref>
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==Disposition==
==Disposition==
*Based on underlying cause
*Based on underlying cause
*One admission criteria is potassium less than 3.0 meq/L and a QTc that is close to or more than 500 msec. <ref>[https://www.emrap.org/episode/emrap2018august/electrolyte EM:RAP 2018 August Electrolyte Emergencies - Part 1 - All Things Potassium]</ref>


==See Also==
==See Also==
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==External Links==
==External Links==
*[https://emcrit.org/ibcc/hypokalemia/ IBCC Hypokalemia]
*[http://ddxof.com/electrolyte-abnormalities/ DDxOf: Differential Diagnosis of Electrolyte Abnormalities]
*[http://ddxof.com/electrolyte-abnormalities/ DDxOf: Differential Diagnosis of Electrolyte Abnormalities]


Latest revision as of 15:57, 10 February 2021

Background

Clinical Features

Differential Diagnosis[1]

Differential diagnosis of hypokalemia

Intracellular Shift

Decreased intake

  • Special diets or those low in potassium
  • Chronic alcohol abuse
  • Fasting
  • Eating disorders

Increased loss

Drugs

Other

  • Acute leukemia and lymphomas
  • Recovery from megaloblastic anemia
  • Hypothermia (accidental or induced)

Evaluation

ECG Hypokalemia.jpg

Management

  • Potassium repletion (PO or IV)
    • Every 10mEq KCl → serum K ↑ ~0.1mEq/L
    • PO preferred (if symptomatic or level is <2.5, both oral and IV should be given)
  • Oral potassium
    • Inexpensive and rapidly absorbed
    • KCl tablet (elixir form available but has poor taste)
    • K-Dur (extended release tablet) is large and may be difficult to swallow
    • If sending patient home can also increase food intake of potassium as an alternative or supplementing potassium tablets. Printable table that can be given to the patient available at this reference: [2].
  • Intravenous potassium
    • Must be given in dilute solutions at slow rate (10meq/hour) to minimize side effects and cardiac toxicity
    • Generally should not give more than 40mEq via IV
    • Side effects: Local tissue burning, phlebitis, sclerosis
  • Also treat Hypomagnesemia if present
  • Re-check ECG after treatment [3]
  • Hypokalemia in acute or recent myocardial infarction places patients at much higher risk for ventricular fibrillation[4]
    • Previous studies and many professional organizations recommend maintaining K between 4.0 - 5.0 mEq/L in MI patients
    • However, more recent studies suggest 3.5 - 4.5 mEq/L results in the lowest mortality

Disposition

  • Based on underlying cause
  • One admission criteria is potassium less than 3.0 meq/L and a QTc that is close to or more than 500 msec. [5]

See Also

External Links

References

  1. ↑ In: Tintinalli JE, Stapczynski J, Ma O, Yealy DM, Meckler GD, Cline DM. eds. Tintinalli’s Emergency Medicine: A Comprehensive Study Guide, 8e. McGraw-Hill; Accessed November 29, 2020. https://accessmedicine.mhmedical.com/content.aspx?bookid=1658&sectionid=109381281
  2. ↑ Potassium Supplement (Oral Route, Parenteral Route) from Mayo Clinic
  3. ↑ Slovis, Corey. "Electrolyte Emergencies". Presentation.
  4. ↑ Goyal A et al. Serum Potassium Levels and Mortality in Acute Myocardial Infarction. JAMA. 2012;307(2):157-164.
  5. ↑ EM:RAP 2018 August Electrolyte Emergencies - Part 1 - All Things Potassium
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