Hypokalemia: Possible Diagnosis
Potassium related content
- Potassium is the major intracellular cation with 98% of the total body
potassium in the intracellular compartment and only 2% located
extracellularly (plasma). The serum potassium level is a measure of
the 2% that is present in the extracellular space.
- Hypokalemia is defined as a serum potassium concentration
of less than 3.5 mEq/L [normal range: 3.5-5 mEq/L].
- Hypokalemia classification:
Mild (3-3.4 mEq/L)
Moderate (2.5 - 2.9 mEq/L)
Severe (< 2.5 mEq/L)
- The patient's BMI has little effect when determining the
amount of potassium required to reach a target level. Conversely,
renal disease can profoundly impact the amount of potassium required.
Potassium below 3.5 mEq/L (ruled out
24hr urinary K+ excretion:
Perform a spot urine potassium-to-creatinine ratio from
a spot urine specimen (Uk:Ucr):
Plasma bicarbonate concentration:
Answer the following questions
evidence suggestive of transcellular shifts?
Is the patient receiving any of the following medications?
- β-Adrenergic agonists (bronchodilators etc).
- Xanthines (theophylline, caffiene)
- Insulin administration or excess
- Amphotericin B
- Acute Glucose load
- Verapamil Overdose
- Chloroquine (Aralen) intoxication
- Barium or cesium Overdose
Are any of the following medical conditions present?
- Delirium Tremens
- Head Injury
- Myocardial Ischemia
- Refeeding Syndrome
- Metabolic Alkalosis
- Familial hypokalemic periodic paralysis
- Anabolic states
Aboujamous H. et al. Evaluation of the Change in Serum Potassium Levels
after Potassium Administration. J Clin Nephrol Ren Care 2016, 2:013.
Because the potassium content of gastric secretion (5–10 mEq/L)
is much less than that of the intestinal secretion (up to 90
mEq/L), loss of a large volume of gastric secretion is needed to
produce substantial potassium depletion.
In an asymptomatic hypokalemic patient with no apparent causes
for potassium depletion or transcellular redistribution,
pseudohypokalemia should be excluded before pursuing an
Transcellular redistribution of potassium may, however,
significantly alter the relationship between serum concentration
and total body deficit. Therefore, potassium repletion should be
guided by close monitoring of serum concentrations and analysis
Hypokalaemia can result from increased loss, transcellular
shift, or decreased intake of potassium. Increased potassium
loss (through the kidney or gastrointestinal tract) is the most
common cause of hypokalaemia.
Less frequently, hypokalaemia can occur as a result of shift of
potassium from the extracellular space into cells.
Rarely, hypokalemia can result from decreased intake of
Aboujamous et al. Evaluation of the Change in Serum Potassium Levels after
Potassium Administration. J Clin Nephrol Ren Care 2016, 2:013,
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