The cause of hypokalemia can often be suggested by considering clinical and laboratory findings.
|
potassium excretion rate low? |
ECF volume contracted? |
hyper-tension present? |
renin levels low? |
Possible Diagnoses |
|
Y |
|
|
|
• diet low in potassium • shift of K+ into ICF • GI loss potassium • prior loss of K+ in urine |
|
N |
Y |
|
|
• vomiting • diuretics • laxatives • Bartter's syndrome |
|
N |
N |
N |
|
• low magnesium • hypertensive causes of hypokalemia |
|
N |
N |
Y |
Y |
• endogenous or exogenous mineralocorticoids |
|
N |
N |
Y |
N |
• renal artery stenosis • malignant hypertension • tumor producing renin |
after Figure 1, page 32 (Halperin, 1992)
where:
• low potassium excretion present if < 15 mmol/day or TTKG < 2
• ECF is extracellular fluid
• ICF is intracellular fluid
|
Age in Years |
Low end of reference range plasma renin activity in ng AI per mL per hour if supine with normal sodium diet |
|
< 1 year |
2.4 |
|
1 - 3 |
1.7 |
|
3 - 5 |
1.0 |
|
5 - 10 |
0.5 |
|
10 - 15 |
0.5 |
|
> 15 |
0.2 |
Purpose: To identify the cause of hypokalemia based on clinical and laboratory findings.
Specialty: Endocrinology, Clinical Laboratory
Objective: clinical diagnosis, including family history for genetics
ICD-10: E87.6,
