Hypokalemia (serum K⁺ <3.5 mmol/l)

Emergency?

Pseudohypokalemia?

Start

Move to therapy

Hypokalemia (serum K⁺ <3.5 mmol/L)

No further workup

Treat accordingly and reevaluate

Treat accordingly ^*

Extrarenal loss/remote renal loss

Renal loss

↑ Tubular flow

Osmotic diuresis

Vomiting
Chloride
Diarrhea

Loop diureticd
Bartter's syndrome

Thiazide diuretic
Gitelman's syndrome

Nonreabsorbable anions other than HCO₃^-

Hippurate
Penicillins

↑  Distal K⁺ secretion

End

Yes

No

Yes

No

Yes

No

Acid-base status

Metabolic acidosis

GI K⁺ loss

Normal

Profuse sweating

Metabolic alkalosis

Remote diuretic use
Remote voliting or stomach drainage
Profuse sweating

BP and/or volume

Low or normal

High

Acid-base status

Variable

Metabolic acidosis

Proximal RTA
Distal RTA
DKA
Amphotericin B
Acetazolamide

Metabolic alkalosis

Aldosterone

High

Low

Cortisol

High

Cushing's syndrome

Normal

Liddle's syndrome
Licorice
AME

Move to therapy

Renin

High

RAS
RST
Malignant HTN

Low

PA
FH-I

Urine K⁺

<15 mmol/d or <15 mmol/g Cr

>15 mmol/g Cr or >15 mmol/d

TTKG

>4

<2

Urine Cl^– (mmol/l)

>20

<10

Urine Ca/Cr (molar ratio)

>0.20

<0.15

Yes

No

Insulin excess
ß₂-Adrenergic agonists
FHPP
Hyperthyroidism
Barium intoxication
Theophylline
Chloroquine

History, physical examination, basic laboratory tests

Clear evidence of low intake

Clear evidence of transcellular shift