History
The history may be vague. Patients are often asymptomatic, particularly with mild hypokalemia. Symptoms are often due to the underlying cause of the hypokalemia rather than the hypokalemia itself. Hypokalemia should be suggested by a constellation of symptoms that involve the GI, renal, musculoskeletal, cardiac, and nervous systems. The patient's medications should be reviewed to ascertain whether any of them could cause hypokalemia.
Common symptoms include the following:
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Palpitations
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Skeletal muscle weakness or cramping
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Paralysis, paresthesias
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Constipation [13]
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Nausea or vomiting
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Abdominal cramping
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Polyuria, nocturia, or polydipsia
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Psychosis, delirium, or hallucinations
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Depression
Physical
Findings that are consistent with severe hypokalemia may include the following:
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Signs of ileus
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Hypotension
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Ventricular arrhythmias [4]
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Cardiac arrest
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Bradycardia or tachycardia
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Premature atrial or ventricular beats
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Hypoventilation, respiratory distress
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Respiratory failure
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Lethargy or other mental status changes
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Decreased muscle strength, fasciculations, or tetany
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Decreased or absent tendon reflexes
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Cushingoid appearance (eg, edema)
Causes
Causes include the following:
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Renal losses
Renal tubular acidosis
Hyperaldosteronism
Magnesium depletion
Leukemia (mechanism uncertain)
A study by Ravioli et al found dyskalemia not only to be common in emergency department patients with acute kidney injury (AKI), but to independently increase the risk of adverse outcomes. Of patients with AKI admitted to a Swiss public hospital’s emergency department, 11% were determined to have hypokalemia, and 13%, hyperkalemia. Current use of thiazide or loop diuretics, as well as a medical reason for emergency department admission, were risk factors for hypokalemia in patients with AKI, while male gender and the use of potassium-sparing diuretics, nonsteroidal anti-inflammatory drugs (NSAIDs), or angiotensin-converting enzyme (ACE) inhibitors reportedly protected against hypokalemia. The presence of potassium levels of less than 2.5 mmol/L or greater than 5.0 mmol/L were found to be independently tied to an increased risk of in-hospital mortality. [14]
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GI losses (source may be medical or psychiatric, ie, anorexia or bulimia)
Vomiting or nasogastric suctioning
Diarrhea
Enemas or laxative use
Ileal loop
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Medication effects
Diuretics (most common cause)
Beta-adrenergic agonists
Steroids
Theophylline
Aminoglycosides
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Transcellular shift
Insulin
Alkalosis
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Malnutrition or decreased dietary intake, parenteral nutrition
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Prominent U waves after T waves in hypokalemia.
