Hypokalemia resident survival guide: Difference between revisions
Rim Halaby (talk | contribs) |
Rim Halaby (talk | contribs) No edit summary |
||
Line 1: | Line 1: | ||
__NOTOC__ | __NOTOC__ | ||
{{CMG}} | {{CMG}}; {{AE}} {{Rim}} | ||
==Overview== | ==Overview== | ||
[[Hypokalemia]] is defined as plasma potassium levels less than 3.5 mEq/L | [[Hypokalemia]] is defined as plasma[[potassium]] levels less than 3.5 mEq/L. [[Hypokalemia]] may present as [[ileus]], muscle cramps, [[rhabdomyolysis]], and [[hypomagnesemia]]. EKG findings may include [[U wave]], flat or inverted T waves, [[prolonged QT interval]], and ventricular ectopy. | ||
==Causes== | ==Causes== | ||
===Life Threatening Causes=== | ===Life Threatening Causes=== | ||
Life-threatening conditions which may result in death or permanent disability within 24 hours if left untreated. | Life-threatening conditions which may result in death or permanent disability within 24 hours if left untreated. | ||
* Metabolic alkalosis | |||
* Diabetic ketoacidosis | |||
===Common Causes=== | ===Common Causes=== | ||
Shown below is a table summarizing the different pathophysiological processes that can lead to hypokalemia. | Shown below is a table summarizing the different pathophysiological processes that can lead to hypokalemia. | ||
{| style="cellpadding=0; cellspacing= 0; width: 900px;" | {| style="cellpadding=0; cellspacing= 0; width: 900px;" | ||
Line 96: | Line 99: | ||
==Management== | ==Management== | ||
* Treat the underlying etiology. | |||
* Dosages for potassium repletion are: | |||
** PO: 40 mEq KCL Q 4-6 hours | |||
** IV (if urgent): 10 mEq/hour KCL | |||
* Recheck potassium levels in 2-4 hours. | |||
* Recheck potassium levels in 2-4 hours | |||
==Do's== | ==Do's== |
Revision as of 22:08, 21 October 2014
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Rim Halaby, M.D. [2]
Overview
Hypokalemia is defined as plasmapotassium levels less than 3.5 mEq/L. Hypokalemia may present as ileus, muscle cramps, rhabdomyolysis, and hypomagnesemia. EKG findings may include U wave, flat or inverted T waves, prolonged QT interval, and ventricular ectopy.
Causes
Life Threatening Causes
Life-threatening conditions which may result in death or permanent disability within 24 hours if left untreated.
- Metabolic alkalosis
- Diabetic ketoacidosis
Common Causes
Shown below is a table summarizing the different pathophysiological processes that can lead to hypokalemia.
Trans-cellular shifts | Renal loss | GI loss | Increased hematopoiesis | Decreased intake of potassium | |
|
Subject is normo or hypotensive
Associated with alkalosis
|
Subject is hypertensive
Secondary hyperaldosteronism
|
Associated with metabolic acidosis
Associated with metabolic alkalosis
|
|
|
Diagnostic Algorithm
Shown below is an algorithm depicting the possible laboratory findings and their interpretation.
Hypokalemia [K+] < 3.5 | |||||||||||||||||||||||||||||||||||||||||||||||
Order: ❑ 24 hours urinary K+ (UK) ❑ Transtubular potassium gradient (TTKG) | |||||||||||||||||||||||||||||||||||||||||||||||
UK > 25-30 mEq/L TTKG > 7 | UK < 25 mEq/L TTKG < 3 | ||||||||||||||||||||||||||||||||||||||||||||||
Renal loss of potassium | GI loss of potassium | ||||||||||||||||||||||||||||||||||||||||||||||
What is the blood pressure? | |||||||||||||||||||||||||||||||||||||||||||||||
Normal or ↓ | ↑ | ||||||||||||||||||||||||||||||||||||||||||||||
Check the acid/base status | Possible etiologies are: Primary aldosteronism Secondary aldosteronism Non aldosterone increase in mineralcorticoids | ||||||||||||||||||||||||||||||||||||||||||||||
Acidemia | Alkalemia | Variable | |||||||||||||||||||||||||||||||||||||||||||||
Check urinary chloride (UCl) | Hypomagnesemia | ↑ Aldosterone ↓ Renin | ↑ Aldosterone ↑ Renin | ↓ Aldosterone | |||||||||||||||||||||||||||||||||||||||||||
UCl < 20 | UCl > 20 | Primary aldosteronism | Secondary aldosteronism | Non aldosterone increase in mineralcorticoids | |||||||||||||||||||||||||||||||||||||||||||
Management
- Treat the underlying etiology.
- Dosages for potassium repletion are:
- PO: 40 mEq KCL Q 4-6 hours
- IV (if urgent): 10 mEq/hour KCL
- Recheck potassium levels in 2-4 hours.