Hypokalemia resident survival guide: Difference between revisions
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===Common Causes=== | ===Common Causes=== | ||
{ | Shown below is a table summarizing the different pathophysiological processes that can lead to hypokalemia. | ||
{{ | {| style="cellpadding=0; cellspacing= 0; width: 900px;" | ||
{{ | |- | ||
{{ | | style="padding: 0 5px; font-size: 100%; background: #4682B4; color: #FFFFFF;" align=center |'''Trans-cellular shifts''' || style="padding: 0 5px; font-size: 100%; background: #4682B4; color: #FFFFFF;" align=center colspan="2"|'''Renal loss''' || style="padding: 0 5px; font-size: 100%; background: #4682B4; color: #FFFFFF;" align=center |'''GI loss'''|| style="padding: 0 5px; font-size: 100%; background: #4682B4; color: #FFFFFF;" align=center |'''Increased hematopoiesis''' || style="padding: 0 5px; font-size: 100%; background: #4682B4; color: #FFFFFF;" align=center |'''Decreased intake of potassium''' | ||
{{ | |- | ||
{{ | |style="font-size: 100; padding: 0 5px; background: #B8B8B8" align=left | | ||
{{ | * Metabolic alkalosis (K+/H+ exchanger) | ||
{{ | * Insulin (activates Na+/K+ ATPase) | ||
{{ | * Catecholamine (activates Na+/K+ ATPase) | ||
{{ | * Hypokalemic thyrotoxic periodic paralysis | ||
{{ | * Hypothermia | ||
{{ | * Chloroquine | ||
{{ | * Barium intoxication | ||
<br> | | * Cesium intoxication | ||
{{ | * Antipsychotic overdose | ||
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'''''Subject is normo or hypotensive'''''<br> | |||
''Associated with acidosis'' | |||
* Diabetic ketoacidosis | |||
* Renal tubular acidosis type 1 | |||
* Renal tubular acidosis type 2 | |||
''Associated with alkalosis'' | |||
* Diuretics | |||
* Vomiting (increase aldosterone) | |||
* Bartter's syndrome (dysfunction of in loop of Henle) | |||
* Gitelman's syndrome (dysfunction in distal convoluted tubules) | |||
* Hypomagnesemia | |||
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'''''Subject is hypertensive'''''<br> | |||
''Primary hyperaldosteronism'' | |||
* Conn's syndrome | |||
''Secondary hyperaldosteronism'' | |||
* Cushing's disease | |||
* Congenital adrenal hyperplasia | |||
* Increased mineralcorticoids | |||
* Licorice ingestion | |||
* Liddle's disease | |||
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''Associated with metabolic acidosis'' | |||
* Diarrhea | |||
* Laxative abuse | |||
* Villous adenoma | |||
''Associated with metabolic alkalosis'' | |||
* Vomiting | |||
* Nasogastric tube drainage | |||
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* Megaloblastic anemia | |||
* Treatment of anemia | |||
* Crisis of AML | |||
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* Tea and toast diet | |||
* Anorexia nervosa | |||
* Alcoholism | |||
|} | |||
==Diagnostic Algorithm== | |||
Shown below is an algorithm depicting the possible laboratory findings and their interpretation. | |||
{{Family tree/start}} | |||
{{Family tree | | | | | | | A00 | | | | | A00= '''Hypokalemia''' <br> '''[K+] < 3.5'''}} | |||
{{Family tree | | | | | | | |!| | | | | | }} | |||
{{Family tree | | | | | | | A01 | | | | | A01= Order: <br> <div style="float: left; text-align: left; width: 12em; padding:1em;">❑ 24 hours urinary K<sup>+</sup> (U<sub>K</sub>)<br> ❑ Transtubular potassium gradient (TTKG) </div>}} | |||
{{Family tree | | | | | |,|-|^|-|.| | | | | | | }} | |||
{{Family tree | | | | | B01 | | B02 | B01= '''U<sub>K</sub> > 25-30 mEq/L''' <br> '''TTKG > 7'''| B02= '''U<sub>K</sub> < 25 mEq/L''' <br> '''TTKG < 3'''| }} | |||
{{Family tree | | | | | |!| | | |!| | | }} | |||
{{Family tree | | | | | C01 | | C02 | C01= '''Renal loss of potassium'''|C02= '''GI loss of potassium'''| }} | |||
{{Family tree | | | | | |!| | | |!| }} | |||
{{Family tree | | | | | C03 | | C04 | C03= <div style="float: left; text-align: left; width: 12em; padding:1em;">'''What is the blood pressure?''' </div>| C04= <div style="float: left; text-align: left; width: 12em; padding:1em;">Possible etiologies are: <br> [[Diarrhea]] <br> [[Laxative]]s <br> [[Villous adenoma]] </div>}} | |||
{{Family tree | | | |,|-|^|-|-|-|-|-|-|-|-|-|.| | | | | }} | |||
{{Family tree | | | D01 | | | | | | | | | | D02 | D01= Normal or ↓| D02= ↑}} | |||
{{Family tree | | | |!| | | | | | | | | | | |!| | | | | }} | |||
{{Family tree | | | E01 | | | | | | | | | | E02 | E01= '''Check the acid/base status'''| E02= <div style="float: left; text-align: left; width: 12em; padding:1em;">Possible etiologies are: <br> [[Primary aldosteronism]] <br> [[Secondary aldosteronism]] <br> Non aldosterone increase in [[mineralcorticoid]]s </div>}} | |||
{{Family tree | |,|-|^|-|v|-|-|-|.| | | | | |!| | }} | |||
{{Family tree | F01 | | F02 | | F03 | | | | F04 | F01= [[Acidemia]]| F02= [[Alkalemia]] | F03= Variable | F04= div style="float: left; text-align: left; width: 12em; padding:1em;">Order: <br> ❑ [[Aldosterone]] <br> ❑ [[Renin]] </div>}} | |||
{{Family tree | |!| | | |!| | | |!| | | |,|-|^|-|v|-|-|.|}} | |||
{{Family tree | G01 | | G02 | | G03 | | G04 | | G05 | | G06 | | G01= <div style="float: left; text-align: left; width: 12em; padding:1em;">Possible etiologies are: <br>[[Diabetic ketoacidosis]] <br> [[Renal tubular acidosis]] </div>| G02= '''Check urinary chloride (U<sub>Cl</sub>)''' | G03= [[Hypomagnesemia]] | G04 = ↑ [[Aldosterone]] <br> ↓ [[Renin]] | G05= ↑ [[Aldosterone]] <br> ↑ [[Renin]]| G06= ↓ [[Aldosterone]]}} | |||
{{Family tree | | | |,|-|^|-|.| | | | | |!| | | |!| | | |!| | }} | |||
{{Family tree | | | H01 | | H02 | | | | H03 | | H04 | | H05 | H01= U<sub>Cl</sub> < 20| H02= U<sub>Cl</sub> > 20 | H03= [[Primary aldosteronism]]| H04= [[Secondary aldosteronism]]| H05= <div style="float: left; text-align: left; width: 12em; padding:1em;">Non aldosterone increase in [[mineralcorticoid]]s </div>}} | |||
{{Family tree | | | |!| | | |!| | }} | |||
{{Family tree | | | I01 | | I02 | I01= <div style="float: left; text-align: left; width: 12em; padding:1em;">Possible etiologies are: <br>[[Vomiting]] <br> [[Nasogastric tube]] </div>| I02= <div style="float: left; text-align: left; width: 12em; padding:1em;">Possible etiologies are: <br> [[Diuretics]] <br> [[Bartter's]] <br> [[Gitelman's]] </div>}} | |||
{{Family tree/end}} | |||
==Management== | ==Management== |
Revision as of 22:02, 21 October 2014
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
Hypokalemia is defined as plasma potassium levels less than 3.5 mEq/L
Causes
Life Threatening Causes
Life-threatening conditions which may result in death or permanent disability within 24 hours if left untreated.
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 | div style="float: left; text-align: left; width: 12em; padding:1em;">Order: ❑ Aldosterone ❑ Renin | ||||||||||||||||||||||||||||||||||||||||||||
Check urinary chloride (UCl) | Hypomagnesemia | ↑ Aldosterone ↓ Renin | ↑ Aldosterone ↑ Renin | ↓ Aldosterone | |||||||||||||||||||||||||||||||||||||||||||
UCl < 20 | UCl > 20 | Primary aldosteronism | Secondary aldosteronism | Non aldosterone increase in mineralcorticoids | |||||||||||||||||||||||||||||||||||||||||||
Management
1) Hypokalemia may present as ileus, muscle cramps, rhabdomyolysis, and hypomagnesemia.
2) Treat the etiology.
3) For severe hypokalemia (K < 2.5 mEq/L)
- EKG findings show 'U' wave, flat or inverted T waves.
- Intravenous KCL 80 mEQ/L @ 10-15mEq/hr with oral KCL 40-80mEq/L
- Recheck potassium levels in 2-4 hours