Electrolyte Emergencies

Bedside management of life-threatening electrolyte disturbances. These are time-critical decisions: obtain ECGs, treat the patient, and re-check the electrolyte frequently.

See also the companion Electrolyte Repletion charts for chronic/ward-based repletion.

Hyperkalemia

When to act

Do not wait for ECG if K is at least 6.5 mEq/L, rising rapidly, or the patient is symptomatic. Obtain ECG early, but start membrane stabilization while the ECG is being obtained.

ECG progression

Finding	Interpretation
Peaked T waves	Early
PR prolongation, QRS widening	Worsening
Sine-wave pattern, bradyarrhythmia, asystole	Pre-arrest

Tiered management

Tier	Intervention	Dose / Notes
First — stabilize myocardium	Calcium gluconate 10%	1 g IV over 5-10 min via large peripheral or central line. Onset 1-3 min; lasts about 30-60 min. Does not lower total body K. Repeat if ECG changes persist. WikEM Hyperkalemia
	Calcium chloride 10%	1 g IV via central line only (extravasation necrosis risk). Use when peripheral access is poor and delay is dangerous.
Second — shift K intracellular	Regular insulin + dextrose	10 units regular insulin IV push + 25 g dextrose IV (D50 50 mL). Onset about 15 min. Monitor glucose q30-60 min; continue dextrose infusion to prevent rebound hypoglycemia.
	Albuterol nebulizer	10-20 mg over 10-20 min. Additive with insulin/dextrose.
	Sodium bicarbonate	150 mEq IV over 15-30 min if metabolic acidosis is present. Less reliable as monotherapy.
Third — remove K from body	Loop diuretics	If volume overloaded and adequate urine output.
	Sodium zirconium cyclosilicate (SZC)	10 g PO/NG TID. Onset within 1 h; not for stand-alone life-threatening hyperkalemia.
	Patiromer	25 g PO daily. Onset 4-7 h; not for acute life-threatening events.
	Hemodialysis	For refractory/severe hyperkalemia, especially with renal failure or life-threatening arrhythmia.

Pearls

• Recheck K frequently after each intervention. Shifts are temporary; K re-equilibrates.
• Calcium first when ECG shows QRS widening or sine waves. Calcium does not lower K; it buys time for insulin/glucose and definitive removal.
• Hypoglycemia after insulin is common; have D10 infusion ready and check glucose serially.
• False hyperkalemia from hemolysis or extreme thrombocytosis/WBC — repeat a non-hemolyzed sample if the clinical picture does not fit.

Hyponatremia

General correction limits

Setting	24-hour limit	Notes
Chronic hyponatremia (over 48 h or unknown)	at most 8 mEq/L	Lower target if high ODS risk: alcoholism, malnutrition, liver disease, hypokalemia
Acute water intoxication / active seizures	Correct more rapidly initially, then keep total 24 h change below 10-12 mEq/L once active treatment begins	Goal is to stop seizures, not to normalize Na

Seizure / severe symptomatic hyponatremia

Step	Action
First-line	3% saline 100 mL IV over 10 min. May repeat up to 3x (total 300 mL) until symptoms improve. IBCC Hyponatremia
Goal	Raise serum Na about 4-6 mEq/L — usually enough to abort seizures.
Recheck	Serum Na q30-60 min during active correction.

ODS prevention

If correction exceeds safe limits or the patient is high-risk, involve nephrology/ICU. Options include therapeutic re-lowering with DDAVP + D5W.

Pearls

• Hypotonic fluids are contraindicated in severe hyponatremia with seizures.
• Symptoms matter more than the number — a Na of 118 with seizures needs urgent treatment; a Na of 118 found incidentally does not.
• Calculate the change per liter if using a continuous 3% saline infusion. A rough rule: 1 L of 3% saline raises serum Na by about 10-12 mEq/L in a 70 kg patient (use actual weight and Na deficit formula for precision).

Hypokalemia and Hypomagnesemia

Hypokalemia

Route	Max replacement rate	Notes
Peripheral IV	10-20 mEq/hr	With cardiac monitoring; stay at the lower end unless ICU
Central IV	up to 40 mEq/hr in ICU	Continuous telemetry; confirm local protocol
Oral	20-40 mEq per dose, up to about 100 mEq/day	Preferred when safe

• Recheck K frequently; aggressive diuresis or ongoing GI losses require ongoing replacement.
• Concurrent alkalosis increases renal K wasting — correct the driver when possible.

Hypomagnesemia

Severity	Dose
Severe (below 1.2 mg/dL) or symptomatic	1-2 g MgSO4 IV over 15 min - 1 h
Asymptomatic	1-2 g MgSO4 IV q6h x 4 doses

Replete magnesium first

Hypomagnesemia is a cofactor in many hypokalemia cases: Mg is required for Na/K-ATPase and ROMK channel function. K will not correct reliably until Mg is repleted. IBCC Hypomagnesemia

Hypercalcemia

Severity	Ca level	Management
Mild	below 12 mg/dL	Oral hydration, treat underlying cause, avoid immobilization
Moderate	12-14 mg/dL	IV normal saline 200-300 mL/h; loop diuretic once euvolemic
Severe / symptomatic	above 14 mg/dL	Aggressive IV NS + calcitonin 4 IU/kg SC/IM q12h (onset 4-6 h, tachyphylaxis within 48 h) + zoledronic acid 4 mg IV over 15 min (onset 24-48 h; renal caution) or pamidronate 60-90 mg IV over 24 h. Hemodialysis if renal failure.

Pearls

• Hydration is first in all symptomatic cases. Loop diuretics only after volume is replete.
• Bisphosphonates take days — they do not rescue acutely unstable patients. Use calcitonin for immediate effect while waiting.
• Denosumab is an option when bisphosphonates are contraindicated (e.g., renal failure).

Hypocalcemia

Presentation	Management
Symptomatic (seizures, tetany, laryngospasm, QT prolongation)	Calcium gluconate 1-2 g IV over 10-20 min. Repeat as needed; consider continuous infusion. IBCC Hypocalcemia
With ECG instability or code situation	Calcium chloride via central line if faster elemental calcium needed
Chronic	Oral calcium +/- vitamin D; calcitriol if 1-alpha-hydroxylation impaired

Pearls

• Check and replete magnesium first. Hypocalcemia often will not correct until Mg is normalized.
• Do not treat by the albumin-corrected calcium alone in acutely ill patients — ionized calcium is the physiologically relevant value.
• Citrate toxicity from massive transfusion or plasma exchange causes ionized hypocalcemia with a normal total calcium.