The Diagnostic Approach to Hypokalemia - Flowchart
The Diagnostic Approach to Hypokalemia - Flowchart
«Flowchart»

Hypokalemia (Serum K+  <3.5 mmol/L)

Hypokalemia (Serum K+  <3.5 mmol/L)

Hypokalemia (Serum K+  <3.5 mmol/L)

+

End

End

End

Move to therapy

Move to therapy

Move to therapy

Yes

Yes

Yes

No

No

No

History, physical examination, and basic laboratory tests

History, physical examination, and basic laboratory tests

History, physical examination, and basic laboratory tests

Clear evidence of low intake

Clear evidence of low intake

Clear evidence of low intake

Clear evidence of transcellular shift

Clear evidence of transcellular shift

Clear evidence of transcellular shift

Treat accordingly and reevaluate

Treat accordingly and reevaluate

Treat accordingly and reevaluate

Yes

Yes

Yes

No

No

No

Extrarenal loss/remote renal loss

Extrarenal loss/remote renal loss

Extrarenal loss/remote renal loss

Renal loss

Renal loss

Renal loss

Urine K+ 

Urine K+ 

Urine K+ 

+

<15 mmol/day OR <15 mmol/g Cr

<15 mmol/day OR <15 mmol/g Cr

<15 mmol/day

>15 mmol/g Cr OR >15 mmol/day

>15 mmol/g Cr OR >15 mmol/day

>15 mmol/g Cr

Treat accordingly

Treat accordingly

Treat accordingly

Yes

Yes

Yes

No

No

No


Insulin excess
2-adrenergic agonists
FHPP
Hyperthyroidism
Barium intoxication
Theophylline
Chloroquine


Insulin excess
2-adrenergic agonists
FHPP
Hyperthyroidism
Barium intoxication
Theophylline
Chloroquine


Insulin excess
2-adrenergic agonists
FHPP
Hyperthyroidism
Barium intoxication
Theophylline
Chloroquine


Insulin excess
2-adrenergic agonists 2
FHPP
Hyperthyroidism
Barium intoxication
Theophylline
Chloroquine

Emergency?

Emergency?

Emergency?

Pseudohypokalemia?

Pseudohypokalemia?

Pseudohypokalemia?

No further workup

No further workup

No further workup

Yes

Yes

Yes

No

No

No

Acid-base status

Acid-base status

Acid-base status

Metabolic acidosis


GI K+  loss

Metabolic acidosis


GI K+  loss


GI K+  loss + Metabolic acidosis

Normal


Profuse sweating

Normal


Profuse sweating


Profuse sweating Normal

Metabolic alkalosis


Remote diuretic use
Remote vomiting or stomach drainage
Profuse sweating

Metabolic alkalosis


Remote diuretic use
Remote vomiting or stomach drainage
Profuse sweating


Remote diuretic use
Remote vomiting or stomach drainage
Profuse sweating Metabolic alkalosis

Tubular flow


Osmotic diuresis

Tubular flow


Osmotic diuresis

Tubular flow


Osmotic diuresis


Osmotic diuresis

Distal K+  secretion

Distal K+  secretion

Distal K+  secretion

+

TTKG

TTKG

TTKG

>4

>4

>4

<2

<2

<2

BP and/or volume

BP and/or volume

BP and/or volume

Low OR normal

Low OR normal

Low OR normal

High

High

High

Non-reabsorbable anions other than HCO3- 


Hippurate
Penicillins

Non-reabsorbable anions other than HCO3- 


Hippurate
Penicillins

Non-reabsorbable anions other than HCO3- 

3 -


Hippurate
Penicillins


Hippurate
Penicillins

Acid-base status

Acid-base status

Acid-base status

Variable

Variable

Variable

Metabolic acidosis


Proximal RTA
Distal RTA
DKA
Amphotericin B
Acetazolamide

Metabolic acidosis


Proximal RTA
Distal RTA
DKA
Amphotericin B
Acetazolamide


Proximal RTA
Distal RTA
DKA
Amphotericin B
Acetazolamide Metabolic acidosis

Metabolic alkalosis

Metabolic alkalosis

Metabolic alkalosis


Vomiting
Chloride diarrhea


Vomiting
Chloride diarrhea


Vomiting
Chloride diarrhea


Vomiting
Chloride diarrhea

Urine Cl-  (mmol/L)

Urine Cl-  (mmol/L)

Urine Cl-  (mmol/L)

-

>20

>20

>20

<10

<10

<10


Thiazide diuretic
Gitelman's syndrome


Thiazide diuretic
Gitelman's syndrome


Thiazide diuretic
Gitelman's syndrome


Thiazide diuretic
Gitelman's syndrome


Loop diuretic
Bartter's syndrome


Loop diuretic
Bartter's syndrome


Loop diuretic
Bartter's syndrome


Loop diuretic
Bartter's syndrome

Urine Ca/Cr (molar ratio)

Urine Ca/Cr (molar ratio)

Urine Ca/Cr (molar ratio)

>0.20

>0.20

>0.20

<0.15

<0.15

<0.15

Aldosterone

Aldosterone

Aldosterone

High

High

High

Low

Low

Low


RAS
RST
Malignant HTN


RAS
RST
Malignant HTN


RAS
RST
Malignant HTN


RAS
RST
Malignant HTN


PA
FH-I


PA
FH-I


PA
FH-I


PA
FH-I

Renin

Renin

Renin

High

High

High

Low

Low

Low


Cushing's syndrome


Cushing's syndrome


Cushing's syndrome


Cushing's syndrome


Liddle's syndrome
Licorice
SAME


Liddle's syndrome
Licorice
SAME


Liddle's syndrome
Licorice
SAME


Liddle's syndrome
Licorice
SAME

Cortisol

Cortisol

Cortisol

High

High

High

Normal

Normal

Normal

bp, blood pressure; DKA, diabetic ketoacidosis; FH-I, familial hyperaldosteronism type I; FHPP, familial hypokalemic periodic paralysis; HTN, hypertension; PA, primary aldosteronism; RAS, renal artery stenosis; RST, renin-secreting tumor; RTA, renal tubular acidosis; SAME, syndrome of apparent mineralocorticoid excess; TTKG, transtubular potassium gradient.

bp, blood pressure; DKA, diabetic ketoacidosis; FH-I, familial hyperaldosteronism type I; FHPP, familial hypokalemic periodic paralysis; HTN, hypertension; PA, primary aldosteronism; RAS, renal artery stenosis; RST, renin-secreting tumor; RTA, renal tubular acidosis; SAME, syndrome of apparent mineralocorticoid excess; TTKG, transtubular potassium gradient.

bp, blood pressure; DKA, diabetic ketoacidosis; FH-I, familial hyperaldosteronism type I; FHPP, familial hypokalemic periodic paralysis; HTN, hypertension; PA, primary aldosteronism; RAS, renal artery stenosis; RST, renin-secreting tumor; RTA, renal tubular acidosis; SAME, syndrome of apparent mineralocorticoid excess; TTKG, transtubular potassium gradient.