Hyperkalaemia — Viva

Opening (30 s)

"Hyperkalaemia — give a one-line definition and the single most important immediate risk." ^[1][2]

Model: Hyperkalaemia is a serum potassium at or above 5.5 mmol/L (Lehnhardt; UKKA/ERC). The immediate risk is fatal arrhythmia. UKKA bands: mild 5.5-5.9, moderate 6.0-6.4, severe at or above 6.5 mmol/L. Calcium follows the ECG; insulin-glucose still runs at a confirmed 6.5. ^[1][2]

Station 1 — Pathophysiology (2 min)

Potassium is the predominant intracellular cation. A rise in extracellular K+ depolarises myocytes, inactivates fast sodium channels, slows conduction (wide QRS) and can dissolve organised activity into sine wave then VF or asystole. ^[3]

Station 2 — Clinical diagnosis (2 min)

Often silent. Symptoms, when present, are non-specific muscular or cardiac dysfunction. Peaked T waves are the most widely appreciated ECG sign and are rarely by themselves life-threatening. Always exclude pseudohyperkalaemia (haemolysis, leucocytosis, thrombocytosis) in the well patient with a normal ECG. ^[1][5]

Red flag cue: K+ at or above 6.5 mmol/L, or any ECG change (peaked T, wide QRS, lost P, sine wave). Give IV calcium if the ECG is abnormal (UKKA 6.8 mmol equivalent — not "10-30 mL" as a single unsourced range). ^[2]

Station 3 — Investigations (2 min)

ECG first. Repeat potassium without a tourniquet or ABG K+. Glucose (hypoglycaemia risk after insulin). Urea, creatinine, gas for acidosis. Cortisol if Addisonian — treat before the result. Digoxin level if relevant. Film if extreme counts. ^[2][5]

Station 4 — Emergency management (3 min)

1. Calcium if ECG abnormal: Long 10 mL 10% gluconate (chloride 10 mL in arrest); UKKA 6.8 mmol equivalent. Does not lower K+. ^[3][2]
2. Insulin 10 units IV with glucose: UKKA 25 g; Harel 50 g with 10 units because almost one fifth became hypoglycaemic. Check glucose hourly 4-6 h and up to 12 h. ^[2][4]
3. Salbutamol 10-20 mg nebulised, adjuvant not monotherapy.
4. Remove: diuretic if output allows, SZC/patiromer, or dialysis. SPS not for emergency severe hyperkalaemia.

Station 5 — Definitive / long-term care (2 min)

Stop K-retaining drugs. Treat the cause. Binders may allow RAAS inhibitors to continue. RALES: spironolactone 25 mg daily cut all-cause death 30 percent in severe HFrEF — do not stop the drug permanently for a number you can bind. ^[6]

Station 6 — Special populations (2 min)

Paediatric: same logic, weight-adjusted local protocol. Older adults: polypharmacy and reduced GFR. Dialysis: missed session is the prototype; HD is definitive. Heart failure plus CKD: use binders to keep RAAS drugs running. ^[1][2][6]

Station 7 — Evidence and pitfalls (2 min)

Name UKKA 2020 for bands and 6.8 mmol calcium. Name Harel for 10-unit insulin and the one-fifth hypoglycaemia figure. Name Long for 10 mL gluconate. Trap: quoting 10 mL gluconate as 10 mmol. Trap: 50 g glucose as the only dose when UKKA uses 25 g. Trap: calcium resonium as emergency removal. ^[2][3][4]

Station 8 — Rapid-fire pearls (1 min)

1. At or above 5.5 / at or above 6.5. 2. Calcium does not lower K+. 3. 6.8 mmol UKKA vs 10 mL gluconate US. 4. 10 units insulin. 5. Salbutamol not monotherapy. 6. Repeat the sample in the well normal-ECG patient. ^[1][2][3]

Examiner pass criteria

• Speaks in sourced numbers, not mixed 10-30 mL / 25 g / 50 g without naming the source
• Gives at least one exact dose or threshold
• Names escalation to dialysis
• Does not delay calcium for a repeat sample when the QRS is already wide ^[2][3]

References6ShowHide

1. [1]Lehnhardt A, Kemper MJ. Pathogenesis, diagnosis and management of hyperkalemia Pediatr Nephrol, 2011.PMID 21181208
2. [2]Alfonzo A, Harrison A, Baines R, Chu A, Mann S, MacRury M. Clinical Practice Guidelines: Treatment of Acute Hyperkalaemia in Adults UK Kidney Association (Renal Association), 2020.Source
3. [3]Long B, Warix JR, Koyfman A. Controversies in Management of Hyperkalemia J Emerg Med, 2018.PMID 29731287
4. [4]Harel Z, Kamel KS. Optimal Dose and Method of Administration of Intravenous Insulin in the Management of Emergency Hyperkalemia: A Systematic Review PLoS One, 2016.PMID 27148740
5. [5]Meng QH, Wagar EA. Pseudohyperkalemia: A new twist on an old phenomenon Crit Rev Clin Lab Sci, 2015.PMID 25319088
6. [6]Pitt B, Zannad F, Remme WJ, et al. The effect of spironolactone on morbidity and mortality in patients with severe heart failure N Engl J Med, 1999.PMID 10471456