Hypokalemia: Difference between revisions
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==Background==
==Background==
Low = <3.5meq/L


Low! = <2.5meq/L
==Clinical Features==
 
*Central nervous system
== Diagnosis  ==
**[[Weakness]]
 
**[[myalgia|Cramps]]
*CNS
**Weakness  
**Cramps  
**Hyporeflexia  
**Hyporeflexia  
*GI
*Gastrointestinal
**Ileus  
**[[Ileus]]
*Renal  
*Renal  
**Met alkalosis  
**[[Metabolic alkalosis]]
*CV
*Cardiovascular
**ECG findings:  
**[[PACs]]/[[PVCs]]
***ST seg depression
**[[ACLS: Bradycardia|Bradycardia]] or [[atrial tachycardia|atrial]]/[[junctional tachycardia]]
***U wave (V4-V6)[[Image:ECG Hypokalemia.jpg|thumb|ECG Hypokalemia.jpg]]  
**[[AV block]]
**Also may cause:
**[[Tachycardia (wide)|Ventricular tachycardia]], [[Adult pulseless arrest|Ventricular fibrillation]]
***PACs/PVCs
 
***Bradycardia or atrial/junctional tachycardia
==Differential Diagnosis==
***AV block
[[File:Hypokalemia.png|thumb|Differential diagnosis of hypokalemia]]
***V tach, V fib
===Intracellular Shift===
*Alkalosis (each 0.10 rise in pH causes 0.5 decrease)
*[[Insulin]]
*[[Beta agonists]]
*[[Hypokalemic periodic paralysis]]


== DDX ==
===Decreased intake===
*Special diets or those low in potassium
*Chronic [[alcohol Abuse|alcohol abuse]]


*Shift
===Increased loss===
**Alkalosis (each 0.10 rise in pH causes 0.5 decrease)
*GI
**Insulin
**[[Vomiting]], [[diarrhea]], fistula
**B-agonist
*Renal
*Decreased intake
**[[Diuretics]]
*Increased loss
**Hyperaldosteronism
**GI (v/d/fistula)
**Renal
***Diuretics
***Hyperaldo
**Exercise
**Exercise
***HyperCa
**[[Hypercalcemia]]
***HypoMg
**[[Hypomagnesemia]]
*Drugs
 
**PCN
===Drugs===
**Lithium
*[[Penicillins]]
**L-dopa
*[[Lithium toxicity|Lithium]]
**Theophyline
*L-dopa
*[[Theophylline]], methylxanthines (e.g. [[caffeine]]
*[[Insulin]]
*Barium
*[[Quinine]]
*Catecholamines
 
==Evaluation==
*Serum potassium level is diagnostic
**Normal = 3.5-5meq/L
**Severe hypokalemia = <2.5meq/L
*Always check magnesium
*Suggestive [[ECG]] findings:
**[[ST segment depression]]
**U wave (V4-V6)
**[[QT prolongation]]
**[[Premature ventricular contraction]]
 
[[Image: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
*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 <ref>Slovis, Corey. "Electrolyte Emergencies". Presentation.</ref>
*Hypokalemia in acute or recent [[myocardial infarction]] places patients at much higher risk for [[ventricular fibrillation]]<ref>Goyal A et al. Serum Potassium Levels and Mortality in Acute Myocardial Infarction. JAMA. 2012;307(2):157-164.</ref>
**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


==Treatment==
==See Also==
*20meq/hr KCl IV or PO
*[[Electrolyte Abnormalities (Main)]]
**every 10meq should inc serum by ~0.1meq/L
*[[Hypokalemic periodic paralysis]]
*Treat hypomag if present
*[[Hyperkalemia]]


==Source ==
==External Links==
Tintinalli's
*[http://ddxof.com/electrolyte-abnormalities/ DDxOf: Differential Diagnosis of Electrolyte Abnormalities]


==References==
<references/>
[[Category:FEN]]
[[Category:FEN]]

Revision as of 16:10, 29 September 2019

Background

Clinical Features

Differential Diagnosis

Differential diagnosis of hypokalemia

Intracellular Shift

Decreased intake

Increased loss

Drugs

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
  • 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 [1]
  • Hypokalemia in acute or recent myocardial infarction places patients at much higher risk for ventricular fibrillation[2]
    • 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

See Also

External Links

References

  1. ↑ Slovis, Corey. "Electrolyte Emergencies". Presentation.
  2. ↑ Goyal A et al. Serum Potassium Levels and Mortality in Acute Myocardial Infarction. JAMA. 2012;307(2):157-164.
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