Overview/Classification #
| Potassium level (mmol/L) | |
| Normal Range (1) | 3.5 – 5.0 mmol/L |
| Mild hyperkalemia | 5.5 – 6.0 mmol/L |
| Moderate hyperkalemia | 6.1 – 7.0 mmol/L |
| Severe hyperkalemia | >7.0 mmol/L + ECG changes |
- Key points:
- The most common cause of an elevated potassium level is due to haemolysis of the blood cells/sampling error (always make sure you repeat the level!)
- $Cardiac disturbances can be a serious complication of hyperkalaemia – always make sure you get an ECG!$
Triage #
Triage category depends on the severity of the serum K+ levels
- Mild to moderate – within hours
- Severe – emergency requiring immediate attention
Causes #
- Spurious (2)
- $Haemolysis – due to rupture of blood cells in the sample during/shortly after the blood draw releasing K+ (this is the most common cause; always repeat the sample first to confirm that it is a true hyperkalaemia)$
- Prolonged tourniquet time
- Increased intake
- IV/oral supplementation
- Blood transfusions
- Reduced output (3)
- Acute/chronic renal disease
- Kidney failure requiring dialysis (should discuss with nephrology as a matter of urgency)
- Cellular shift (3)
- Acidosis
- Insulin deficiency
- Tissue destruction
- $Medications$ (2,4)
- Spironolactone
- Amiloride
- ACE inhibitors (-pril)
- ARBS (-sartan)
- NSAIDs (aspirin, ibuprofen)
- Beta blockers (-olol)
- Other – e.g. digoxin (in toxicity), heparin, trimethoprim, movicol
Clinical features #
Signs and symptoms can often be very vague and non-specific (5)
| Symptoms | Signs |
| Muscle weakness Fatigued SOB Muscular paralysis Palpitations Chest pain | Bradycardia (secondary to heart block) Tachypnoea (from respiratory muscle weakness) Muscle weakness and flaccid paralysis Depressed/absent tendon reflexes |
Investigations #
Initial investigations
| Investigation | Significance |
| VBG | Repeat sampleMonitor for acidosis |
| UEC | Serum K+ |
| ECG | Look for cardiac disturbances that may result from high levels of K+ (in order of severity). For examples of ECG changes refer to: https://litfl.com/hyperkalaemia-ecg-library/ {hyperlink to website} (6)Tall tented T wavesP wave widening/flattening PR prolongation, disappearance of P wavesbradyarrhythmias Widening of QRSSine waveVF |
Management #
| Initial steps: REPEAT/confirm the measurement (on a gas) +/- a formal UEC + CMP if nil recent ECG Consider causes and contributing medications or supplements |
Management – Mild hyperkalaemia (5.5 – 6.0 mmol/L) (1,2,7) #
- Initial steps (above) plus:
| Resonium 15 – 30g POorResonium 30 – 50g PR daily if not tolerating PO/NBM |
- Recheck K+ within 4-6 hrs, cease resonium when possible
Management – Moderate hyperkalaemia (6.1 – 7.0mmol/L) (1,2) #
- Initial steps (above) plus:
- Notify senior clinician
| 10 units actrapid + 50 ml of 50% glucose over 5 mins (Get nursing staff to check BSLs at 15 mins, 30 mins then hourly for 6 hrs) |
- Recheck K+ within 1-2 hrs
Management – Severe hyperkalaemia (>7.0 mmol/L + ECG changes) (1,2) #
- Initial steps (above) plus:
- Notify senior clinician – will likely need cardiac monitoring running with management
| If evidence of arrhythmia on ECG or QRS widening, consider giving: #10 ml calcium gluconate 10% IV over 2-3 minsCan repeat to max 50 mls until ECG stabilises {{Note: Calcium works to antagonise the cardiac effects of hyperkalaemia, however it does not lower the K+ level (see below)}} {{Beware: avoid using calcium in patients on digoxin (may precipitate ventricular arrhythmias)}} (8) |
| To reduce the serum K+ level: 10 units actrapid + 50 ml of 50% dextrose over 5 minsGet nursing staff to check BSLs at 15 mins, 30 mins then hrly for 6 hrs plus Nebulised salbutamol 10mg over 30 mins for synergistic effectUse only 5mg if patient has a history of ischaemic heart disease Other options: loop diuretics (e.g. furosemide) (9), #sodium bicarbonate (10), newer therapies (e.g. #patiromer oral suspension (11) |
{{Note, newer therapies including patiromer may not yet be supplied by hospitals in Australia}}
References #
1. Clinical Guideline: Management of Hyperkalaemia in Inpatients and the Emergency Department Austin Health 2018
2. Marshall S, Ruedy J. On Call: Principles and Protocols (3rd Edition). In: Brown AF, Cadogan M, Celenza A, editors. On Call: Principles and Protocols. Pennsylvania W.B. Saunders & Company
3. Mount DB. Causes and evaluation of hyperkalemia in adults. Table: Major causes of hyperkalemia; UpToDate 2021 [Available from: https://www.uptodate.com/contents/causes-and-evaluation-of-hyperkalemia-in-adults
4. Ben Salem C, Badreddine A, Fathallah N, Slim R, Hmouda H. Drug-induced hyperkalemia. Drug Saf. 2014 Sep;37(9):677-92. doi: 10.1007/s40264-014-0196-1. PMID: 25047526.
5. Jones C, Border D, Jones A, Turnock D, Lloyd F. Guidelines for dealing with adult patients with hyperkalaemia in the community NHS; 2021 [Available from: https://www.yorkhospitals.nhs.uk/seecmsfile/?id=3483&inline=1.
6. Buttner R, Burns E. Hyperkalaemia Life in the Fast Lane 2021 [Available from: https://litfl.com/hyperkalaemia-ecg-library/.
7. 2008. Hyperkalaemia – Management of Acute Hyperkalaemia in Adults. Clinical Procedure. Canberra: Canberra Hospital and Health Services.
8. Bower JO, Mengle HAK. The additive effect of calcium and digitalis: a warning, with a report of two deaths. JAMA 1936;106: 1511–53. doi:10.1001/jama.1936.02770140013004
9. Rastergar A, Soleimani M. Hypokalaemia and hyperkalaemia. Postgrad Med J. 2001;77:759–64.
10. Dépret, F., Peacock, W.F., Liu, K.D. et al. Management of hyperkalemia in the acutely ill patient. Ann. Intensive Care 9, 32 (2019). https://doi.org/10.1186/s13613-019-0509-8
11. Blair HA. Patiromer: A Review in Hyperkalaemia. Clin Drug Investig. 2018 Aug;38(8):785-794. doi: 10.1007/s40261-018-0675-8. PMID: 30030701.
Contributors
Reviewing Consultant/Senior Registrar
Dr Michelle Truong
Dr Adam Steinberg
