Learning objectives

• Definition, diagnosis, and management of hyperkalemia

Definition

• Hyperkalemia is an elevated level of potassium (K+) in the blood:
  • Mild: a serum K+ 5.5 – 5.9 mmol/L
  • Moderate: a serum K+6.0-6.4 mmol/L
  • Severe: a serum K+  ≥ 6.5  mmol/L

Signs and symptoms

• Gastro-intestinal
  • Nausea
  • Vomiting
  • Diarrhea
• Neuromuscular 
  • Paresthesias
  • Muscle fasciculations
  • Ascending paralysis of the extremities (quadriplegia)
• Cardiac
  • Dyspnea
  • Progressive ECG changes with increasing severity of hyperkalemia
    • Peaked T wave
    • Wide PR interval
    • Wide QRS duration
    • Loss of P wave
    • Sinusoidal wave

Causes

Management

• First, ensure that the lab result is correct and rule out pseudohyperkalemia
• Typical examples:
  • Poor storage of blood specimens
  • Long transport time from blood draw of the sample to processing in the lab

Suggested reading

• Lott C, Truhlář A, Alfonzo A, et al. European Resuscitation Council Guidelines 2021: Cardiac arrest in special circumstances [published correction appears in Resuscitation. 2021 Oct;167:91-92]. Resuscitation. 2021;161:152-219.
• Palmer BF, Carrero JJ, Clegg DJ, et al. Clinical Management of Hyperkalemia. Mayo Clin Proc. 2021;96(3):744-762.
• Palmer BF, Clegg DJ. Diagnosis and treatment of hyperkalemia. Cleve Clin J Med. 2017;84(12):934-942. doi:10.3949/ccjm.84a.17056

Clinical updates

Jessen et al. (Resuscitation, 2025) conducted a systematic review and meta-analysis showing that insulin with glucose lowers serum potassium by about 0.7 mmol/L within 60 minutes, while inhaled or IV beta₂-agonists (e.g., salbutamol) reduce potassium by 0.9–1.0 mmol/L, with combination therapy achieving up to a 1.2 mmol/L reduction. In contrast, bicarbonate showed no meaningful potassium-lowering effect, and there is no high-quality evidence that calcium improves outcomes beyond membrane stabilization. These findings support insulin–glucose and beta₂-agonists as first-line therapies for acute hyperkalemia and call for re-evaluation of routine bicarbonate and calcium use.

• Read more about this study HERE.
• Listen to NYSORA’s podcast discussing this HERE.

Glahn et al. (British Journal of Anaesthesia, 2025) highlight in the updated 2024 EMHG guidelines that severe hyperkalemia is a key life-threatening feature of malignant hyperthermia (MH) and requires immediate treatment alongside dantrolene. Recommended management includes IV insulin with dextrose, IV calcium chloride or gluconate for membrane stabilization, beta₂-agonists, and dialysis in refractory cases, with close potassium and ECG monitoring. The guideline reinforces structured, protocol-driven hyperkalemia treatment as a core component of MH crisis management to prevent arrhythmias and cardiac arrest.

• Read more about this study HERE.