Prehospital Care
Be attentive to the ABCs.
If the patient is severely bradycardic or manifesting cardiac arrhythmias, appropriate pharmacologic therapy or cardiac pacing should be considered.
Emergency Department Care
Emergency department care includes the following:
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Patients in whom severe hypokalemia is suspected should be placed on a cardiac monitor; establish intravenous access and assess respiratory status.
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Direct potassium replacement therapy by the symptomatology and the potassium level. Begin therapy after laboratory confirmation of the diagnosis.
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Patients who have mild or moderate hypokalemia (potassium level of 2.5-3.5 mEq/L) are usually asymptomatic; if these patients have only minor symptoms, they may need only oral potassium replacement therapy. Patients with mild hypokalemia whose underlying cause of hypokalemia can be corrected may not need any potassium replacement, such as those with vomiting successfully treated with antiemetics. If cardiac arrhythmias or significant symptoms are present, then more aggressive therapy is warranted. This treatment is similar to the treatment of severe hypokalemia.
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If the potassium level is less than 2.5 mEq/L, intravenous potassium should be given. Admission or ED observation is indicated; replacement therapy takes more than a few hours.
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The serum potassium level is difficult to replenish if the serum magnesium level is also low. Look to replace both.
Patients should be transferred only after any cardiac arrhythmias have been treated and the condition has been stabilized. Depending on the level of hypokalemia, an advanced cardiac life support (ACLS) ambulance should be used to allow continuous cardiac monitoring during transport.
The aforementioned study by Makinouchi et al determined that no electrocardiographic exams were performed in 30% of emergency department patients with severe hypokalemia and that for about 40% of individuals in the emergency department with severe hypokalemia, intravenous potassium replacement was not provided within 24 hours of presentation. Therefore, the investigators suggested that emergency department patients with severe hypokalemia may be receiving suboptimal management. [9]
Consultations
An internist or a nephrologist should be consulted for admission or follow-up care.
Consider psychiatric consultation in laxative abuse, anorexia, or bulimia cases. [15]
Medical Care
Further inpatient care involves continuing intravenous replacement of potassium as needed, cardiac monitoring in severe hypokalemia, and repeating potassium level measurements every 1-3 hours.
Identify the etiology of the hypokalemia.
Consider switching to potassium-sparing diuretic if diuretic therapy is needed. Take 40 mEq KCI daily for 2-3 days and repeat the potassium level.
Complications
Replacing potassium too quickly can cause a rapid rise in the blood potassium level, leading to a relative hyperkalemia with subsequent cardiac complications.
If hypokalemia is not corrected easily with replacement therapy, search for other coexistent metabolic abnormalities (eg, hypomagnesemia). Hypokalemia may be refractory to treatment until hypomagnesemia is corrected.
Hypokalemia can potentiate digitalis toxicity in patients who are taking digoxin.
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Prominent U waves after T waves in hypokalemia.
