Click here to Enlarge
Hyperkalaemia is defined as serum potassium level higher than 5.5 mmol/L.
Causes of raised potassium plasma levels- Haemolysed blood and prolonged or tight application of torniquet shift of potassium from blood cells to blood plasma by mechanical trauma Lab errors Thrombocytosis Leukocytosis ( ^^ WBC ) Lab errors Infectious mononucleosis Leukaemia Familial psedohyperkalaemia Dietary Supplements Total parenteral nutritional formulas Pencillin G Potassium therapy PRBC tranfusion Once GFR falls < 15-20 sig hyperkalaemia can occur even in abscence of an abnormally large K+ load Potassium sparing diuretics NSAIDs ACE inhibitors Angiotensin receptor blockers Cyclosporine or Tacrolimus Trimethoprim -sulfamethoxazole Heparin Ketoconazole Herbs Diabetes mellitus Sickle cell disease or Trait Lower urinary tract obstruction Adrenal insufficiency Primary Addison’s syndrome ( Autoimmune dis , TB or infarct ) Enzyme deficiencies Genetic disorders Metabolic acidosis Beta adrenergic blockade Acute tubular necrosis Electrical burns Thermal burns Cell depolarization Head trauma Digitalis toxicity Digitalis toxicity Methotrexate Rhabdomyolysis Tumour lysis syndrome Cyclosporine
Approach-Often incidental laboratory finding Rarely associated with symptoms Compains may be vague Ocassionally patients may c/o palpitations , nausea , muscle pain or paraesthesia , generalised fatigue Clinical affects are due to pathological effects of ↑ K+ conc on generation of action potentials in excitable tissues ( Heart and Neuromuscular tissue )
Assessment –Cardiac function ( eg ECG ) Renal function Kidneys and Urinary tract Hydration status ( fluid over load ) Blood pressure ( vol depletion ) Neurological evaluation Medications
Tests to consider –Glucose Bicarbonate Blood Urea Nitrogen Serum creatinine Serum calcium Full Blood Count ECG All patients K+ value >= 6.0 should have a 12 lead ECG done urgently Cortisol and Alosterone ( r/o Addisons ) Urinalysis ( Rhabdomyolysis ) Creatinine phosphokinase ( CPK ) and Calcium ( r/o Rhabdomyolysis ) ABG ( r/o acidosis ) Digoxin levels ( if on treatment ) Transtubular potassium gradient ( assessment of renal potassium handling ) Plasma renin activity Urine and plasma osmolality
Threshold for emergency treatment varies but most guidelines recommend that emergency treatment should be given if the serum K+ is >= 6.5 mmol/L with or without ECG changes If hyperkalaemia suspected on clinical grounds or ECG changes
ECG Changes–Causes a rapid reduction in resting membrane potential leading to ↑ ed cardiac depolarization and muscle excitability → this causes ECG changes ECG changes do not consistently follow a stepwise , dose-dependent pattern Risk of arrythmias ↑es with K+ values > 6.5 mmol and even a small elevation in K + above this conc can lead to rapid progression from peaked T waves to VF and asystole ECG changes may be normal even in presence of sig hyperkalaemia ECG changes may also be modified by the presence of co-existing metabolic disorders such as metabolic acidosis , Ca conc , Na conc and the rate of ↑ in K+ level It can affect the function of both temporary and permanent pacemakers
Pseudohyperkalaemia is also known by other names as ○ spurious ○ factitious ○ artefactual One of the most common testing errors in clinical laboratory It is defined as reported rise in serum K+ conc with normal effective plasma potassium concentration The most common cause is poor technique or practice during collection and preanalytic processing of blood sample Patient factors predisposing to psuedohyperkalaemia include ○ inherited defects in erythrocyte membrane structure ○ marked ↑ in platelet counts ○ marked ↑ in WCC Consider if ↑↑ platelets in blood or leucocytes coincide with unexplained serum hyperkalaemia , typically in a patient who is known to suffer with renal problems or acidosis or who is does not take medications like ACEi’s and cardiac glycosides
Severity and Urgency–Refer urgently to secondary care ( same day ) if ○ K+ > 6.5 mmol / L ○ ECG changes and K + > 5.5 mmol/L ○ Potassium levels have risen > 0.5 mmol/L in the last 6-12 hrs All patients with K + > = 6 should have an ECG urgently Patients with chronic hyperkalaemia may be asymptomatic ( for e.g those with CKD ) at increased levels , while patients with dramatic acute potassium shifts may develop severe symptoms at lower ones
Due to ↑ risk of fatal arrythmias , hyperkalaemia needs urgent treament if its causing ECG abnormalities or the plasma K+ level is more than 6.5 mmol/L
Tall tented T waves Can also widen the T wave so that entire ST segment is incorporated into the upstroke of the T waves May also cause Flattenning and even loss of the P wave ↑ of PR interval Widening of the QRS complex Arrthymias
Trend – pattern –Look at previous values GFR , creatinine As discussed consider pseudohyperkalaemia if isolated rise in serum K + or unexpected result Arrange for an urgent repeat if level > 6.0 mmol /L If repeat shows a rapid rise in K + for e.g > 0.5 mmol in 24 hrs – arrange admission
Clinical situation –Check for clinical symptoms for e.g ○ lethargy ○ nausea ○ muscle weakness ○ paraesthesia Is the patient in urinary retention ? Acidosis e.g diabetic ketoacidosis AKI or CKD Review prescribed medications Urine output h/o severe trauma ? rhabdomyolysis- consider this is patients who ○ have laid immobile for uncertain period of time ( atleast + 1 hour ) ○ have taken drugs like cocaine , ecstasy or heroin ○ intensive exercise + heat exhaustion ○ septic patients
–Medication related hyperkalaemia is common Commonly used medications implicated are ○ ACE inhibitors ○ ARBs ○ NSAIDs ○ Aspirin ○ Potassium sparing diuretics ○ Aldosterone receptor antagonists ○ Beta blockers ○ Potassium containing laxatives as Movicol and fybogel ○ Heparin and LMWH If suspected withold the medication and repeat test in 1-2 weeks
Emergency treatment-Protect the heart Shift K+ out of cells Remove K+ from body Monitor K+ and glucose Prevent recurrence
LINKS AND RESOURCES
PATIENT INFORMATION
NHS on potassium tests https://www.nhs.uk/conditions/potassium-test/
A superb presentation for patients from Kidneyfund.org- American Kidney Foundation about hyperkalemia https://www.kidneyfund.org/kidney-disease/chronic-kidney-disease-ckd/complications/high-potassium-hyperkalemia.html
For patients who are advised a low potassium diet by Kidney Care and The Renal Association https://renal.org/wp-content/uploads/2017/06/KCUK-Potassium_web.pdf
A complete patient education resource on potassium and kidneys by the National Kidney Foundation https://www.kidney.org/sites/default/files/01-10-7269_ABG_PatBro_Hyperkalemiap7.pdf
Brilliant work for patients by The American Heart Association with a downloadable leaflet https://www.heart.org/en/health-topics/heart-failure/treatment-options-for-heart-failure/hyperkalemia-high-potassium
American Association of Kidney Patients has a useful page for patients with raised potassium https://aakp.org/center-for-patient-research-and-education/hyperkalemia/
INFORMATION FOR CLINICIANS ON HYPERKALEMIA
Best Practice in managing hyperkalaemia in CKD by National Kidney Foundation https://www.kidney.org/sites/default/files/02-10-7259%20Hyperkalemia%20Tool.pdf
Emergency management of hyperkalaemia in adults by the Renal Association https://renal.org/wp-content/uploads/2017/10/HYPERKALAEMIA-ALGORITHM-MARCH-2014.pdf
ECG changes in hyperkalaemia from Emergency Medicine cases –https://emergencymedicinecases.com/wp-content/uploads/2016/09/Episode-086-Sep2016-Hyperkalemia.pdf
Brilliant summary from Acadoodle on hyperkalemia ( must read ) https://acadoodle.com/articles/5-ecg-changes-of-hyperkalemia-you-need-to-know
Watch a 15 sec You Tube video on ECG changes https://www.youtube.com/watch?v=PxoRJN3SVZQ
European Society of cardiology-Third in a series on hyperkalemia: current views on the treatment of hyperkalemia Vol. 14, N° 13 – 07 Jun 2016 Dr. Anjan Dasgupta https://www.escardio.org/Journals/E-Journal-of-Cardiology-Practice/Volume-14/fourteen-thirteen
Beat the nephrologist ! – read the 104 page guideline ” Treatment of acute Hyperkalaemia in adults ” https://renal.org/guidelines/
References;
- Medscape Hyperkalemia Updated: Apr 09, 2020 http://emedicine.medscape.com/article/240903-overview Author: Eleanor Lederer, MD, FASN; Chief Editor: Vecihi Batuman, MD, FASN et al
- Clinical Chemistry E- Book – William J Marshall , Stephen K Bangert , Marta Lapsley ; Hyperkalaemia
- Merck Manual Hyperkalemia James L. Lewis, III , MD, Brookwood Baptist Health and Saint Vincent’s Ascension Health, Birmingham https://www.msdmanuals.com/en-gb/professional/endocrine-and-metabolic-disorders/electrolyte-disorders/hyperkalemia
- Lehnhardt, Anja, and Markus J Kemper. “Pathogenesis, diagnosis and management of hyperkalemia.” Pediatric nephrology (Berlin, Germany) vol. 26,3 (2011): 377-84. doi:10.1007/s00467-010-1699-3 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3061004/
- Electrocardiogram manifestations in hyperkalaemia- available Ronny Cohen1*, Rhadames Ramos1 , Christine A. Garcia2 , Sohail Mehmood1 , Yoojin Park2 ,
Anthony Divittis1 , Brooks Mirrer1 World Journal of Cardiovascular Diseases, 2012, 2, 57-63 WJCD http://dx.doi.org/10.4236/wjcd.2012.22010 Published Online April 2012 (http://www.SciRP.org/journal/wjcd/) http://file.scirp.org/pdf/WJCD20120200002_21775315.pdf - Treatment of acute Hyperkalaemia in adults ; Renal Association March 2014 http://www.renal.org/guidelines/joint-guidelines/ treatment-of-acute-hyperkalaemia-in-adults#sthash.9XJDQ8aK.dpbs
- Acid-base , fluids and electrolytes – Robert F Reilly , Jr.,Mark A.Perazella
- Making sense of ECG – Andrew R Houghton , David Gray Simon LV, Hashmi MF, Farrell MW.
- Simon LV, Hashmi MF, Farrell MW. Hyperkalemia. [Updated 2019 Dec 10]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2020 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK470284/
- Pseudohyperkalaemia from acutetesting.org by Chris Higgins accessed via https://acutecaretesting.org/en/articles/pseudohyperkalemia
- BLOOD SCIENCES DEPARTMENT OF CLINICAL BIOCHEMISTRY
Title of Document: Hyperkalaemia in primary care Q Pulse Reference No
: BS/CB/DCB/PROTOCOLS/40 Version NO : 9 Authoriser: Paul Thomas Page 1 of 3
https://www.nbt.nhs.uk/sites/default/files/Hyperkalaemia%20in%20Primary%20Care.pdf - Kovesdy, Csaba P. “Epidemiology of hyperkalemia: an update.” Kidney international supplements vol. 6,1 (2016): 3-6. doi:10.1016/j.kisu.2016.01.002