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Hyperkalaemia

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⚡ Hyperkalaemia is a medical emergency. Electrolyte abnormalities are part of the MLA. Rising plasma [K⁺] causes partial membrane depolarisation → inactivation of Na⁺ channels → risk of cardioplegia, muscle paralysis, and death. 💉 Calcium gluconate is preferred (less irritating to veins than calcium chloride).

🚑 Emergency Management: K⁺ >6.5 mmol/L or >6.0 mmol/L with ECG changes
📟 Telemetry + ECG + IV access. Resend bloods if unexpected (exclude haemolysis). 💉 30 mL 10% Calcium Gluconate IV slow (5–10 min). Repeat if ECG changes persist. OR 💉 10 mL 10% Calcium Chloride IV slow (5–10 min). Repeat if ECG changes persist. 💉 10 U short-acting insulin (Actrapid) + 50 mL of 50% glucose IV over 15–30 min. 💊 Lokelma (SZC) 10 g TDS up to 72 h. 🌬️ Salbutamol 5–20 mg nebulised (caution: IHD/arrhythmia). 💧 IV fluids as appropriate. Always identify & treat the cause. 💧 Stop drugs containing K or K retaining 💧 Hypervolaemia: Consider IV Frusemide to remove K 🔁 If K⁺ remains high but not critical, repeat in 1–2 h. 💧 Consider haemodialysis ASAP if Renal failure 💉 Cardiac arrest: IV Sodium Bicarbonate 50 mL 8.4% (especially if metabolic acidosis)

🚑 Emergency Management: K⁺ >6.5 mmol/L or >6.0 mmol/L with ECG changes

📟 Telemetry + ECG + IV access. Resend bloods if unexpected (exclude haemolysis).
💉 30 mL 10% Calcium Gluconate IV slow (5–10 min). Repeat if ECG changes persist.
💉 10 mL 10% Calcium Chloride IV slow (5–10 min). Repeat if ECG changes persist.
💉 10 U short-acting insulin (Actrapid) + 50 mL of 50% glucose IV over 15–30 min.
💊 Lokelma (SZC) 10 g TDS up to 72 h.
🌬️ Salbutamol 5–20 mg nebulised (caution: IHD/arrhythmia).
💧 IV fluids as appropriate. Always identify & treat the cause.
💧 Stop drugs containing K or K retaining
💧 Hypervolaemia: Consider IV Frusemide to remove K
🔁 If K⁺ remains high but not critical, repeat in 1–2 h.
💧 Consider haemodialysis ASAP if Renal failure
💉 Cardiac arrest: IV Sodium Bicarbonate 50 mL 8.4% (especially if metabolic acidosis)

📉 ECG Changes (Act Fast!)

⚠️ Tented T waves → Broad QRS → Bradycardia → Sinewave → VT/VF → Asystole
Flat/absent P waves often precede collapse.

🧠 Physiology

High [K⁺] inactivates Na⁺ channels → ineffective action potentials → conduction block.
IV calcium works by enhancing conduction through L-type Ca²⁺ channels (resistant to K⁺ effects).
This restores excitability but does not lower K⁺.

📋 Aetiology (Check Drug Chart!)

🩺 CKD/AKI, missed dialysis
💊 Drugs: ACEi, ARBs, spironolactone, eplerenone, amiloride, NSAIDs, ciclosporin, trimethoprim, heparin
🧬 Addison’s, Type 4 RTA, congenital adrenal enzyme defects
🩸 Rhabdomyolysis, trauma, burns, tumour lysis, transfusion, haemolysis
🍫 High-K⁺ diet (chocolate, fruit juice, salt substitutes)
⚠️ Pseudohyperkalaemia: haemolysed sample, fist clenching, lab error

🧾 Clinical Features

Often asymptomatic → 🫀 arrhythmias may be first sign
Weakness, cramps, paraesthesia
Hypotension, bradycardia → cardiac arrest

📊 Severity

Mild: 5.5–5.9 mmol/L
Moderate: 6.0–6.4 mmol/L
Severe: ≥6.5 mmol/L or ECG changes → 🚨 emergency

🔬 Investigations

FBC (haemolysis, anaemia), LDH
CK (rhabdomyolysis)
U&E, Ca, Mg; repeat if unexpected
VBG/ABG (metabolic acidosis)
ECG (tented T → sinewave → VT/VF)

⚕️ Management Summary

Stop offending drugs 🚫
IV access + fluids (unless overloaded)
Calcium gluconate IV if ECG changes
Insulin + glucose infusion
Nebulised salbutamol
Consider furosemide if volume status allows
Resins (Lokelma) as bridge
Repeat U&E q2h, ECG monitoring
If refractory/severe → dialysis

💔 Hyperkalaemia in Cardiac Arrest

Confirm K⁺ >6.5 mmol/L (blood gas)
10 mL 10% Calcium chloride IV bolus (can repeat)
10 U insulin + 25 g glucose IV bolus, then glucose infusion
50 mmol NaHCO₃ (50 mL 8.4%) IV if severe acidosis
Dialysis if refractory
Consider mechanical CPR device / ECLS if prolonged

📚 References

Cases — Hyperkalaemia

Case 1: A 68-year-old man with CKD stage 4 and poorly controlled hypertension presents with muscle weakness. ECG shows tall, tented T-waves. Serum potassium is 6.8 mmol/L. Management: IV calcium gluconate for cardiac membrane stabilisation, IV insulin with dextrose to shift K⁺ intracellularly, nebulised salbutamol, and oral sodium zirconium cyclosilicate. Loop diuretic started, and his ramipril held.
Outcome: Potassium falls to 5.0 mmol/L over 6 hours, symptoms resolve, and he is discharged after nephrology review.
Case 2: A 42-year-old man with poorly controlled type 1 diabetes presents with vomiting and dehydration. Labs show diabetic ketoacidosis with potassium 7.2 mmol/L. ECG: absent P-waves, widened QRS. Management: IV calcium gluconate, insulin/dextrose infusion, aggressive fluid resuscitation with normal saline, and close cardiac monitoring. Outcome: As acidosis corrects, K⁺ shifts intracellularly and falls rapidly; potassium replacement is later required to prevent hypokalaemia. He recovers fully after 4 days in hospital.
Case 3: A 79-year-old woman on spironolactone and an ACE inhibitor for heart failure presents after a collapse. Potassium 8.1 mmol/L. She is bradycardic (HR 38), hypotensive, and her ECG shows sine-wave complexes. Management: Immediate IV calcium chloride, repeated insulin/dextrose, IV sodium bicarbonate (metabolic acidosis present), and IV furosemide. Emergency haemodialysis organised. Outcome: ROSC achieved after transient cardiac arrest during dialysis initiation. Survives to discharge after 2 weeks but ACE inhibitor permanently discontinued.

Teaching Commentary 🧑‍⚕️

Hyperkalaemia is life-threatening because of its effects on cardiac conduction. Early ECG changes (tall T-waves, PR prolongation) progress to sine-wave and arrest. Management principles: 1) Stabilise the myocardium (calcium salts), 2) Shift potassium into cells (insulin/dextrose, salbutamol, bicarbonate if acidotic), 3) Remove potassium (resins, diuretics, dialysis). Case 1 shows chronic renal disease, Case 2 highlights acidosis-driven hyperkalaemia in DKA, and Case 3 demonstrates the deadly drug–renal interaction in elderly patients. Always treat both the serum potassium and the underlying cause.

PLEASE NOTE LEGAL ADVICE: The contents are under continuing development and improvements and may contain errors of omission or fact. Feedback vital and always welcome at drokane at gmail.com. This is not to be used for the assessment, diagnosis or management of patients. It should not be regarded as medical advice. It is only for educational purposes. Please adhere to your local protocols. If you are unwell please seek healthcare advice from your doctor. This does not replace senior or specialist advice. If you do not accept this then please do not use the website. If you need medical advice, please consult a doctor or other appropriate medical professional. If you are a medical professional and you need advice then speak to your senior or colleagues.

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